National Emission Standards for Hazardous Air Pollutants: Plywood
and Composite Wood Products; Effluent Limitations Guidelines and
Standards for the Timber Products Point Source Category; List of
Hazardous Air Pollutants, Lesser Quantity Designations, Source Category
List
[Federal Register: July 30, 2004 (Volume 69, Number 146)]
[Rules and Regulations]
[Page 45943-45992]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr30jy04-30]
[[Page 45944]]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 63 and 429
[OAR-2003-0048, FRL-7634-1]
RIN 2060-AG52
National Emission Standards for Hazardous Air Pollutants: Plywood
and Composite Wood Products; Effluent Limitations Guidelines and
Standards for the Timber Products Point Source Category; List of
Hazardous Air Pollutants, Lesser Quantity Designations, Source Category
List
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This action promulgates national emission standards for
hazardous air pollutants (NESHAP) for the plywood and composite wood
products (PCWP) source category under the Clean Air Act (CAA) and
revisions to the effluent limitations, guidelines and standards for the
timber products processing source category under the Clean Water Act (CWA).
The EPA has determined that the PCWP source category contains major
sources of hazardous air pollutants (HAP), including, but not limited
to, acetaldehyde, acrolein, formaldehyde, methanol, phenol, and
propionaldehyde. These HAP are associated with a variety of adverse
health effects. These adverse health effects include chronic health
disorders (e.g., damage to nasal membranes, gastrointestinal
irritation) and acute health disorders (e.g., irritation of eyes,
throat, and mucous membranes, dizziness, headache, and nausea). Three
of the six primary HAP emitted have been classified as probable or
possible human carcinogens. This action will implement section 112(d)
of the CAA by requiring all major sources subject to the final rule to
meet HAP emission standards reflecting the application of the maximum
achievable control technology (MACT). The final rule will reduce HAP
emissions from the PCWP source category by approximately 5,900 to 9,900
megagrams per year (Mg/yr) (6,600 to 11,000 tons per year (tons/yr)).
In addition, the final rule will reduce emissions of volatile organic
compounds (VOC) by 13,000 to 25,000 Mg/yr (14,000 to 27,000 tons/yr).
The EPA is also amending the effluent limitations, guidelines and
standards for the timber products processing point source category
(veneer, plywood, dry process hardboard, particleboard manufacturing
subcategories). The amendments adjust the definition of process
wastewater to exclude certain sources of wastewater generated by air
pollution control devices expected to be installed to comply with the
final PCWP NESHAP.
The EPA is also amending the list of categories that was developed
pursuant to section 112(c)(1) of the CAA. The EPA is delisting a low-
risk subcategory of the PCWP source category. This action is being
taken in part to respond to comments submitted by the American Forest &
Paper Association (AF&PA) and in part upon the Administrator's own
motion, pursuant to section 112(c)(9) of the CAA. This action is based
on EPA's evaluation of the available information concerning the
potential hazards from exposure to HAP emitted by PCWP affected
sources, and includes a detailed rationale for removing low-risk PCWP
affected sources from the source category list.
DATES: The final NESHAP and the amendments to the effluent guidelines
are effective September 28, 2004. The incorporation by reference of
certain publications listed in the final NESHAP is approved by the
director of the Office of the Federal Register as of September 28, 2004.
ADDRESSES: Docket numbers OAR-2003-0048 and A-98-44, containing
supporting documentation used in development of this action, are
available for public viewing at the EPA Docket Center (Air Docket), EPA
West, Room B-108, 1301 Constitution Avenue, NW., Washington, DC 20460.
These dockets also contain documentation supporting the amendments to
40 CFR part 429.
FOR FURTHER INFORMATION CONTACT: For further information concerning
applicability and rule determinations, contact the appropriate State or
local agency representative. If no State or local representative is
available, contact the EPA Regional Office staff listed in 40 CFR
63.13. For information concerning the analyses performed in developing
the final rule, contact Ms. Mary Tom Kissell, Waste and Chemical
Processes Group, Emission Standards Division (C439-03), U.S. EPA,
Research Triangle Park, North Carolina 27711, telephone number (919)
541-4516, electronic mail (e-mail) address kissell.mary@epa.gov. For
information concerning test methods, sampling, and monitoring
information, contact Mr. Gary McAlister, Source Measurement Analysis
Group, Emission Monitoring and Analysis Division (D243-02), U.S. EPA,
Research Triangle Park, North Carolina 27711, telephone number (919)
541-1062, e-mail address mcalister.gary@epa.gov. For information
concerning the economic impacts and benefit analysis, contact Mr. Larry
Sorrels, Innovative Strategies and Economics Group, Air Quality
Strategies and Standards Division (C339-01), U.S. EPA, Research
Triangle Park, North Carolina 27711, telephone number (919) 541-5041,
e-mail address sorrels.larry@epa.gov. For information concerning the
effluent guidelines, contact Mr. Donald Anderson, Engineering and
Analysis Division (4303T), U.S. EPA, 1200 Pennsylvania Avenue, NW.,
Washington, DC 20460, telephone number (202) 566-1021,
anderson.donaldf@epa.gov.
SUPPLEMENTARY INFORMATION: Regulated Entities. Categories and entities
potentially regulated by this action include:
----------------------------------------------------------------------------------------------------------------
SIC code NAICS Examples of regulated
Category Rule a code b entities
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Industry............................. NESHAP................. 2421 321999 Sawmills with lumber kilns.
2435 321211 Hardwood plywood and veneer
plants.
2436 321212 Softwood plywood and veneer
plants.
2493 321219 Reconstituted wood products
(particleboard, medium
density fiberboard,
hardboard, fiberboard, and
oriented strandboard
plants).
2439 321213 Structural Wood Members, Not
Elsewhere Classified
(engineered wood products
plants).
Effluent Guidelines.................. ....................... 2436 321212 Softwood plywood and veneer
plants.
2493 321219 Reconstituted wood products
(particleboard, medium
density fiberboard,
hardboard, fiberboard, and
oriented strandboard
plants).
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\a\ Standard Industrial Classification.
\b\ North American Industrial Classification System.
[[Page 45945]]
This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
action. To determine whether your facility is regulated by this action,
you should examine the applicability criteria in Sec. 63.2231 of the
final rule. If you have any questions regarding the applicability of
this action to a particular entity, consult the person listed in the
preceding FOR FURTHER INFORMATION CONTACT section.
Docket. The EPA has established an official public docket for this
action including both Docket ID No. OAR-2003-0048 and Docket ID No. A-
98-44. The official public docket consists of the documents
specifically referenced in this action, any public comments received,
and other information related to this action. All items may not be
listed under both docket numbers, so interested parties should inspect
both docket numbers to ensure that they have received all materials
relevant to this rule. Although a part of the official docket, the
public docket does not include Confidential Business Information or
other information whose disclosure is restricted by statute. The
official public docket is available for public viewing at the EPA
Docket Center (Air Docket), EPA West, Room B-102, 1301 Constitution
Avenue, NW., Washington, DC. The EPA Docket Center Public Reading Room
is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding
legal holidays. The telephone number for the Public Reading Room is
(202) 566-1744, and the telephone number for the Air Docket is (202)
566-1742.
Electronic Access. You may access this Federal Register document
electronically through the EPA Internet under the Federal Register
listings at http://www.epa.gov/fedrgstr/ You may also access a copy
of this document through the Technology Transfer Network (TTN) at http://
www.epa.gov/ttn/atw/plypart/plywoodpg.html. An electronic version of
the public docket is available through EPA's electronic public docket
and comment system, EPA Dockets. You may use EPA Dockets at http://
www.epa.gov/edocket/ to view public comments, access the index listing
of the contents of the official public docket, and access those
documents in the public docket that are available electronically.
Although not all docket materials may be available electronically, you
may still access any of the publicly available docket materials through
the docket facility identified above. Once in the system, select
``search,'' then key in the appropriate docket identification number.
Judicial Review. Under section 307(b)(1) of the CAA, judicial
review of the standards and limitations of the final rule is available
only by filing a petition for review in the U.S. Court of Appeals for
the District of Columbia Circuit by September 28, 2004. Under section
307(d)(7)(B) of the CAA, only an objection to the final rule that was
raised with reasonable specificity during the period for public comment
can be raised during judicial review. Under section 509(b)(1) of the
CWA, judicial review of today's effluent limitations guidelines and
standards is available in the United States Court of Appeals by filing
a petition for review within 120 days from the date of promulgation of
those guidelines and standards. In accordance with 40 CFR 23.2, the
water portion of today's final rule shall be considered promulgated for
the purposes of judicial review at 1 p.m. Eastern time on August 13,
2004. Moreover, under section 307(b)(2) of the CAA and section
509(b)(2) of the CWA, the requirements established by the final rule
may not be challenged separately in any civil or criminal proceedings
brought by EPA to enforce the requirements.
Outline. The information presented in this preamble is organized as
follows:
I. Introduction
A. What Is the Source of Authority for Development of Today's
Regulations?
B. What Criteria Are Used in the Development of NESHAP?
C. How Was the Final Rule Developed?
D. What Are the Health Effects of the Pollutants Emitted From
the PCWP Industry?
E. Incorporation by Reference of NCASI Test Methods
F. Incorporation by Reference of ASTM Test Method
II. Summary of the Final Rule
A. What Process Units Are Subject to the Final Rule?
B. What Pollutants Are Regulated by the Final Rule?
C. What Are the Compliance Options?
D. What Operating Requirements Are in the Final Rule?
E. What Are the Work Practice Requirements?
F. When Must I Comply With the Final Rule?
G. How Do I Demonstrate Initial Compliance With the Final Rule?
H. How do I Demonstrate Continuous Compliance With the Final Rule?
I. How Do I Demonstrate That My Affected Source Is Part of the
Low-risk Subcategory?
III. Summary of Environmental, Energy, and Economic Impacts
A. How Many Facilities Are Impacted by the Final Rule?
B. What Are the Air Quality Impacts?
C. What Are the Water Quality Impacts?
D. What Are the Solid Waste Impacts?
E. What Are the Energy Impacts?
F. What Are the Cost Impacts?
G. What Are the Economic Impacts?
H. What Are the Social Costs and Benefits?
IV. Summary of Responses to Major Comments and Changes to the
Plywood and Composite Wood Products NESHAP
A. Applicability
B. Overlap With Other Rules
C. Amendments to the Effluent Guidelines for Timber Products Processing
D. Existing Source MACT
E. New Source MACT
F. Definition of Control Device
G. Compliance Options
H. Testing and Monitoring Requirements
I. Routine Control Device Maintenance Exemption (RCDME)
J. Startup, Shutdown, and Malfunction (SSM)
K. Risk-Based Approaches
V. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Analysis
D. Unfunded Mandates Reform Act
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
G. Executive Order 13045: Protection of Children From
Environmental Health & Safety Risks
H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
I. National Technology Transfer and Advancement Act
J. Congressional Review Act
I. Introduction
A. What Is the Source of Authority for Development of Today's Regulations?
Section 112(c) of the CAA requires us to list categories and
subcategories of major sources and area sources of HAP and to establish
NESHAP for the listed source categories and subcategories. The PCWP
source category was originally listed as the plywood and particleboard
source category on July 16, 1992 (57 FR 31576). The name of the source
category was changed to plywood and composite wood products on November
18, 1999 (64 FR 63025), to more accurately reflect the types of
manufacturing facilities covered by the source category. In addition,
when we proposed the PCWP rule on January 9, 2003 (68 FR 1276), we
broadened the scope of the source category to include lumber kilns
located at stand-alone kiln-dried lumber manufacturing facilities or at
any other type of facility. Major sources of HAP are those that have
the potential to emit 9.1 Mg/yr (10 tons/yr) or more of any one HAP or
22.3 Mg/yr (25 tons/yr) or more of any combination of HAP.
Section 112(d) of the CAA directs us to adopt emission standards for
[[Page 45946]]
categories and subcategories of HAP sources. In cases where emission
standards are not feasible, section 112(h) of the CAA allows us to
develop design, equipment, work practice, and/or operational standards.
The collection of compliance options, operating requirements, and work
practice requirements in today's final rule make up the emission
standards and work practice standards for the PCWP NESHAP.
We are promulgating the amendments to 40 CFR part 429 under the
authority of sections 301, 304, 306, 307, 308, 402, and 501 of the CWA.
Section 112(c)(9) of the CAA allows us to delete categories and
subcategories from the list of HAP sources to be subject to MACT
standards under section 112(d) of the CAA, if certain substantive
criteria are met. (The EPA construes this authority to apply to listed
subcategories because doing so is logical in the context of the general
regulatory scheme established by the statute, and is reasonable since
section 112(c)(9)(B)(ii) expressly refers to subcategories.) To delete
a category or subcategory the Administrator must make an initial
demonstration that no source in the category or subcategory: (1) Emits
carcinogens in amounts that may result in a lifetime cancer risk
exceeding one in a million to the individual most exposed; (2) emits
noncarcinogens in amounts that exceed a level which is adequate to
provide an ample margin of safety to protect public health; and (3)
emits any HAP or combination of HAP in amounts that will result in an
adverse environmental effect, as defined by section 112(a)(7) of the CAA.
B. What Criteria Are Used in the Development of NESHAP?
Section 112(d)(1) of the CAA requires that we establish NESHAP for
the control of HAP from both new and existing major sources. Section
112(d)(2) of the CAA requires the NESHAP to reflect the maximum degree
of reduction in emissions of HAP that is achievable. This level of
control is commonly referred to as the MACT.
The MACT floor is the minimum control level allowed for NESHAP and
is defined under section 112(d)(3) of the CAA. In essence, the MACT
floor ensures that the standard is set at a level that ensures that all
major sources achieve a level of control at least as stringent as that
already achieved by the better-controlled and lower-emitting sources in
each source category or subcategory. For new sources, the MACT floor
cannot be less stringent than the emission control that is achieved in
practice by the best-controlled similar source. The MACT standards for
existing sources can be less stringent than standards for new sources,
but they cannot be less stringent than the average emission limitation
achieved by the best-performing 12 percent of existing sources in the
category or subcategory (or the best-performing 5 sources for
categories or subcategories with fewer than 30 sources).
In developing MACT under section 112(d)(2) of the CAA, we must also
consider any control options that are more stringent than the floor. We
may establish standards more stringent than the floor based on the
consideration of cost of achieving the emissions reductions, any non-
air quality health and environmental impacts, and energy requirements.
C. How Was the Final Rule Developed?
We proposed standards for PCWP on January 9, 2003 (68 FR 1276). The
preamble for the proposed standards described the rationale for the
proposed standards. Public comments were solicited at the time of
proposal. The public comment period lasted from January 9, 2003, to
March 10, 2003. Industry representatives, regulatory agencies,
environmental groups, and the general public were given the opportunity
to comment on the proposed rule and to provide additional information
during the public comment period. We also offered at proposal the
opportunity for a public hearing concerning the proposed rule, but no
hearing was requested. We met with stakeholders on several occasions.
We received a total of 57 public comment letters on the proposed
rule during the comment period. Comments were submitted by industry
trade associations, PCWP companies, State regulatory agencies, local
government agencies, and environmental groups. Today's final rule
reflects our consideration of all of the comments received during the
comment period. Major public comments on the proposed rule, along with
our responses to those comments, are summarized in this preamble.
D. What Are the Health Effects of the Pollutants Emitted From the PCWP
Industry?
The final rule protects air quality and promotes the public health
by reducing emissions of some of the HAP listed in section 112(b)(1) of
the CAA. The organic HAP from PCWP process units that have been
detected in one or more emission tests include acetaldehyde,
acetophenone, acrolein, benzene, biphenyl, bromomethane, carbon
disulfide, carbon tetrachloride, chloroform, chloroethane,
chloromethane, cresols, cumene, ethyl benzene, formaldehyde,
hydroquinone methanol, methylene chloride, methylene diphenyl
diisocyanate (MDI), methyl ethyl ketone (MEK), methyl isobutyl ketone
(MIBK), n-hexane, phenol, propionaldehyde, styrene, toluene, xylenes,
1,1,1-trichloroethane, bis-(2-ethylhexyl phthalate), 4-methyl-2-
pentanone, and di-n-butyl phthalate. Many of these HAP are rarely
detected and occur infrequently. The predominant organic HAP emitted
(i.e., those most likely to be emitted in detectable quantities and
with high mass relative to other HAP) by PCWP facilities include
acetaldehyde, acrolein, formaldehyde, methanol, phenol, and
propionaldehyde. Exposure to these compounds has been demonstrated to
cause adverse health effects when present in concentrations higher than
those typically found in ambient air. This section discusses the health
effects associated with the predominant HAP emitted by the PCWP
industry, as well as the health effects of the HAP contributing the
most to cancer and noncancer risks associated with these PCWP
facilities (organic HAP and some metal HAP) that must be included in
any demonstration of eligibility for the low-risk subcategory of PCWP
sources.
We do not have the necessary data on each PCWP facility and the
people living around each facility to determine the actual population
exposures to the HAP emitted from these facilities and the potential
health effects. Our screening assessment, conducted using health-
protective assumptions, indicates that potential noncancer health
impacts were negligible to target organ systems other than the central
nervous and respiratory systems. Furthermore, only acrolein and
formaldehyde showed the potential for acute exposures of any concern.
Therefore, noncancer effects other than those effecting the central
nervous or respiratory systems are not expected to occur prior to or
after regulation, and are provided below only to illustrate the nature
of the contaminant's effects at high dose. However, to the extent the
adverse effects do occur, today's final rule would reduce emissions by
sources subject to the standards and subsequent exposures to such emissions.
1. Acetaldehyde
Acetaldehyde is ubiquitous in the environment and may be formed in
the body from the breakdown of ethanol (ethyl alcohol). In humans,
symptoms of chronic (long-term) exposure to
[[Page 45947]]
acetaldehyde resemble those of alcoholism. Long-term inhalation
exposure studies in animals reported effects on the nasal epithelium
and mucous membranes, growth retardation, and increased kidney weight.
We have classified acetaldehyde as a probable human carcinogen (Group
B2) based on animal studies that have shown nasal tumors in rats and
laryngeal tumors in hamsters.
2. Acrolein
Acute (short-term) inhalation exposure to acrolein may result in
upper respiratory tract irritation and congestion. The major effects
from chronic (long-term) inhalation exposure to acrolein in humans
consist of general respiratory congestion and eye, nose, and throat
irritation. Acrolein is a strong dermal irritant in humans. We consider
acrolein to be a possible human carcinogen (Group C) based on limited
animal cancer data suggesting an increased incidence of tumors in rats
exposed to acrolein in the drinking water.
3. Formaldehyde
Both acute (short-term) and chronic (long-term) exposure to
formaldehyde irritates the eyes, nose, and throat. Limited human
studies have reported an association between formaldehyde exposure and
lung and nasopharyngeal cancer. Animal inhalation studies have reported
an increased incidence of nasal squamous cell cancer. We consider
formaldehyde a probable human carcinogen (Group B2).
4. Methanol
Chronic (long-term) exposure of humans to methanol by inhalation or
ingestion may result in blurred vision, headache, dizziness, and
nausea. No information is available on the reproductive, developmental,
or carcinogenic effects of methanol in humans. Birth defects have been
observed in the offspring of rats and mice exposed to high
concentrations of methanol by inhalation. A methanol inhalation study
using rhesus monkeys reported a decrease in the length of pregnancy and
limited evidence of impaired learning ability in offspring. We have not
classified methanol with respect to carcinogenicity.
5. Phenol
Oral exposure to small amounts of phenol may cause irregular
breathing and muscular weakness. Anorexia, progressive weight loss,
diarrhea, vertigo, salivation, and a dark coloration of the urine have
been reported in chronically (long-term) exposed humans.
Gastrointestinal irritation and blood and liver effects have also been
reported. No studies of developmental or reproductive effects of phenol
in humans are available, but animal studies have reported reduced fetal
body weights, growth retardation, and abnormal development in the
offspring of animals exposed to relatively high doses of phenol by the
oral route. We have classified phenol in Group D, not classifiable as
to human carcinogenicity.
6. Propionaldehyde
Animal studies have reported that inhalation exposure to high
levels of propionaldehyde results in anesthesia and liver damage. No
information is available on the chronic (long-term), reproductive,
developmental, or carcinogenic effects of propionaldehyde in animals or
humans. We have not classified propionaldehyde for carcinogenicity.
7. Arsenic
Chronic (long-term) inhalation exposure to inorganic arsenic in
humans is associated with irritation of the skin and mucous membranes.
Human data suggest a relationship between inhalation exposure of women
working at or living near metal smelters and an increased risk of
reproductive effects. Inorganic arsenic exposure in humans by the
inhalation route has been shown to be strongly associated with lung
cancer. We have classified inorganic arsenic as a Group A, human carcinogen.
8. Beryllium
Chronic (long-term) inhalation exposure of humans to beryllium has
been reported to cause chronic beryllium disease (berylliosis), in
which granulomatous (noncancerous) lesions develop in the lung.
Inhalation exposure to beryllium has been demonstrated to cause lung
cancer in rats and monkeys. Human studies are limited, but suggest a
causal relationship between beryllium exposure and an increased risk of
lung cancer. We have classified beryllium as a Group B1, probable human
carcinogen, when inhaled; data are inadequate to determine whether
beryllium is carcinogenic when ingested.
9. Cadmium
Chronic (long-term) inhalation or oral exposure to cadmium leads to
a build-up of cadmium in the kidneys that can cause kidney disease.
Cadmium has been shown to be a developmental toxicant at high doses in
animals, resulting in fetal malformations and other effects, but no
conclusive evidence exists in humans. Animal studies have demonstrated
an increase in lung cancer from long-term inhalation exposure to
cadmium. We have classified cadmium as a Group B1, probable human
carcinogen when inhaled; data are inadequate to determine whether
cadmium is carcinogenic when ingested.
10. Chromium
Chromium may be emitted from PCWP facilities in two forms,
trivalent chromium (chromium III) or hexavalent chromium (chromium VI).
The respiratory tract is the major target organ for chromium VI
toxicity. Bronchitis, decreased pulmonary function, pneumonia, and
other respiratory effects have been noted from chronic high
concentration exposure. Limited human studies suggest that chromium VI
inhalation exposure may be associated with complications during
pregnancy and childbirth, while animal studies have not reported
reproductive effects from inhalation exposure to chromium VI. Human and
animal studies have clearly established that inhaled chromium VI is a
carcinogen, resulting in an increased risk of lung cancer. We have
classified chromium VI as a Group A, human carcinogen by the inhalation
exposure route.
Chromium III is much less toxic than chromium VI. The respiratory
tract is also the major target organ for chromium III toxicity, similar
to chromium VI. Chromium III is an essential element in humans, with a
daily oral intake of 50 to 200 micrograms per day ([mu]g/d) recommended
for an adult. Data on adverse effects of high oral exposures of
chromium III are not available for humans, but a study with mice
suggests possible damage to the male reproductive tract. We have not
classified chromium III for carcinogenicity.
11. Manganese
Health effects in humans have been associated with both
deficiencies and excess intakes of manganese. Chronic (long-term)
exposure to low levels of manganese in the diet is considered to be
nutritionally essential in humans, with a recommended daily allowance
of 2 to 5 milligrams per day (mg/d). Chronic inhalation exposure to
high levels of manganese by inhalation in humans results primarily in
central nervous system (CNS) effects. Visual reaction time, hand
steadiness, and eye-hand coordination were affected in chronically-
exposed workers. Impotence and loss of libido have been noted in male
workers afflicted with manganism
[[Page 45948]]
attributed to high-dose inhalation exposures. We have classified
manganese as Group D, not classifiable as to human carcinogenicity.
12. Nickel
Nickel is an essential element in some animal species, and it has
been suggested it may be essential for human nutrition. Nickel
dermatitis, consisting of itching of the fingers, hands, and forearms,
is the most common effect in humans from chronic (long-term) skin
contact with nickel. Respiratory effects have also been reported in
humans from inhalation exposure to nickel. No information is available
regarding the reproductive or developmental effects of nickel in
humans, but animal studies have reported such effects, although a
consistent dose-response relationship has not been seen. The forms of
nickel which might be emitted from PCWP facilities include soluble
nickel, nickel subsulfide, and nickel carbonyl. We have classified
nickel refinery dust and nickel subsulfide as Group A, human
carcinogens, and nickel carbonyl as a Group B2, probable human
carcinogen, by inhalation exposure. Human and animal studies have
reported an increased risk of lung and nasal cancers from exposure to
nickel refinery dusts and nickel subsulfide. Animal inhalation studies
of soluble nickel compounds (i.e., nickel carbonyl) have reported lung
tumors.
13. Lead
Elemental lead may cause a variety of effects at low oral or
inhaled dose levels. Chronic (long-term) exposure to high levels of
lead in humans results in effects on the blood, CNS, blood pressure,
and kidneys. Children are particularly sensitive to the chronic effects
of lead, with slowed cognitive development, reduced growth, and other
effects reported. Reproductive effects, such as decreased sperm count
in men and spontaneous abortions in women, have been associated with
lead exposure. The developing fetus is at particular risk from maternal
lead exposure, with low birth weight and slowed postnatal
neurobehavioral development noted. Human studies are inconclusive
regarding lead exposure and cancer, while animal studies have reported
an increase in kidney cancer from lead exposure by the oral route. We
have classified lead as a Group B2, probable human carcinogen.
14. MDI
The MDI has been observed to irritate the skin and eyes of rabbits.
Chronic (long-term) inhalation exposure to MDI may cause asthma,
dyspnea, and other respiratory impairments in workers. We have
classified MDI within Group D, not classifiable as to human carcinogenicity.
15. Benzene
Chronic (long-term) inhalation exposure has caused various
disorders in the blood, including reduced numbers of red blood cells.
Increased incidence of leukemia (cancer of the tissues that form white
blood cells) has been observed in humans occupationally exposed to
benzene. We have classified benzene as a Group A, known human carcinogen.
E. Incorporation by Reference of NCASI Test Methods
Today's final rule amends 40 CFR 63.14 by revising paragraph (f) to
incorporate by reference two test methods developed by the National
Council of the Paper Industry for Air and Stream Improvement (NCASI):
(1) Method CI/WP-98.01, ``Chilled Impinger Method for Use at Wood
Products Mills to Measure Formaldehyde, Methanol, and Phenol'; and (2)
NCASI Method IM/CAN/WP-99.02, ``Impinger/Canister Source Sampling
Method for Selected HAPs and Other Compounds at Wood Products
Facilities.'' These methods are available from NCASI, Methods Manual,
P.O. Box 133318, Research Triangle Park, NC 27709-3318 or at http://
www.ncasi.org. 
They are also available from the docket for the
final rule (Docket Number OAR-2003-0048 and Docket Number A-98-44). These
documents were approved for incorporation by reference by the Director
of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR
part 51.
F. Incorporation by Reference of ASTM Test Method
Today's final rule amends 40 CFR 63.14 by adding paragraph (b)(54)
to incorporate by reference a test method developed by the American
Society for Testing and Materials (ASTM), ASTM D6348-03, ``Standard
Test Method for Determination of Gaseous Compounds by Extractive Direct
Interface Fourier Transform Infrared (FTIR) Spectroscopy.'' This test
method is available from ASTM, 100 Barr Harbor Drive, Post Office Box
C700, West Conshohocken, PA 19428-2959; or ProQuest, 300 North Zeeb
Road, Ann Arbor, MI 48106. This document has been approved for
incorporation by reference by the Director of the Federal Register in
accordance with 5 U.S.C. 552(a) and 1 CFR 51.
II. Summary of the Final Rule
A. What Process Units Are Subject to the Final Rule?
The final rule regulates HAP emissions from PCWP facilities that
are major sources. Plywood and composite wood products are manufactured
by bonding wood material (fibers, particles, strands, etc.) or
agricultural fiber, generally with resin under heat and pressure, to
form a structural panel or engineered wood product. Plywood and
composite wood products manufacturing facilities also include
facilities that manufacture dry veneer and lumber kilns located at any
facility. Plywood and composite wood products include (but are not
limited to) plywood, veneer, particleboard, oriented strandboard,
hardboard, fiberboard, medium density fiberboard, laminated strand
lumber, laminated veneer lumber, wood I-joists, kiln-dried lumber, and
glue-laminated beams. Table 1 of this preamble lists the process units
at PCWP facilities and indicates which process units are subject to the
control requirements in today's final rule. ``Process unit'' means
equipment classified according to its function such as a blender,
dryer, press, former, or board cooler.
The affected source for the final rule is the combination of all
PCWP manufacturing operations, including PCWP process units, onsite
storage of raw materials, onsite wastewater treatment operations
associated with PCWP manufacturing, and miscellaneous coating
operations located at a major source facility. One of the implications
of this definition of affected source is that the control requirements,
or ``floor,'' as defined in section 112(d)(3), are determined for the
entire PCWP facility. Therefore, except for lumber kilns not otherwise
located at PCWP facilities, the final rule contains the control
requirements that represent the MACT level of control for the entire
facility. For lumber kilns not otherwise located at PCWP facilities,
the final rule contains the control requirements that represent the
MACT level of control only for lumber kilns.
[[Page 45949]]
Table 1.--Process Units That Are Subject to the Final Control
Requirements
------------------------------------------------------------------------
Does today's final rule include
control requirements for . . .
For the following process units ---------------------------------------
. . . Existing affected New affected
sources? sources?
------------------------------------------------------------------------
Softwood veneer dryers a; Yes. Yes.
primary tube dryers; secondary
tube dryers; rotary strand
dryers; conveyor strand dryers;
green rotary dryers; hardboard
ovens; reconstituted wood
product presses; and
pressurized refiners.
Press predryers; fiberboard mat No. Yes.
dryers; and board coolers.
Dry rotary dryers a; veneer No. No.
redryers a; softwood plywood
presses; hardwood plywood
presses; engineered wood
products presses; hardwood
veneer dryers a; humidifiers;
atmospheric refiners; formers;
blenders; rotary agricultural
fiber dryers; agricultural
fiber board presses; sanders;
saws; fiber washers; chippers;
log vats; lumber kilns; storage
tanks; wastewater operations;
miscellaneous coating
operations (including group 1
miscellaneous coating
operations a); and stand-alone
digesters.
------------------------------------------------------------------------
a These process units have work practice requirements in today's final
rule in addition to or instead of control requirements. Group 1
miscellaneous coating operations include application of edge seals,
nail lines, logo (or other information) paint, shelving edge fillers,
trademark/grade-stamp inks, and wood putty patches to PCWP (except
kiln-dried lumber) on the same site where the PCWP are manufactured.
Group 1 miscellaneous coating operations also include application of
synthetic patches to plywood at new affected sources.
B. What Pollutants Are Regulated by the Final Rule?
The final rule regulates HAP emissions from PCWP facilities. For
the purpose of compliance with 40 CFR part 63, subpart DDDD, we defined
``total HAP'' to be the sum of the emissions of six primary HAP emitted
from PCWP manufacturing. The six HAP that define total HAP make up 96
percent of the nationwide HAP emissions from PCWP facilities and are
acetaldehyde, acrolein, formaldehyde, methanol, phenol, and
propionaldehyde. Other HAP are sometimes emitted and controlled along
with these six HAP, but in lower quantities. Depending upon which of
the compliance alternatives you choose, you could be required to
measure emissions of total HAP, total hydrocarbon (THC), methanol, or
formaldehyde as surrogates for measuring all HAP. For the purpose of
determining whether your facility is a major source, you would have to
include all HAP as prescribed by rules and guidance pertaining to
determination of major source.
C. What Are the Compliance Options?
Today's final rule includes a range of compliance options, which
are summarized in the following subsections. You must use one of the
compliance options to show compliance with the final rule. In most
cases, the compliance options are the same for new and existing
sources. Dilution to achieve compliance is prohibited, as specified in
40 CFR 63.4.
1. Production-Based Compliance Options
Today's final rule includes production-based compliance options
(PBCO), which are based on total HAP and vary according to type of
process unit. Total HAP emissions are defined in today's final rule as
the total mass emissions of the following six HAP: acetaldehyde,
acrolein, formaldehyde, methanol, phenol, and propionaldehyde. The PBCO
are in units of mass of pollutant per unit of production. Add-on
control systems may not be used to meet the production-based compliance
options. For pressurized refiners and most dryers, the PBCO are
expressed as pounds per oven-dried-ton of wood (lb/ODT). For presses,
hardboard ovens, and some dryers, the PBCO are expressed as pounds per
thousand square feet of board (lb/MSF), with a reference board
thickness. There is no PBCO for conveyor strand dryers.
2. Add-On Control System Compliance Options
If you operate a process unit equipped with an add-on control
system, you may use any one of the following six compliance options.
``Add-on control system'' or ``control system'' means the combination
of capture and control devices used to reduce HAP emissions to the
atmosphere.
(1) Reduce THC emissions (as carbon, and minus methane if you wish
to subtract methane) by 90 percent.
(2) Reduce methanol emissions by 90 percent.
(3) Reduce formaldehyde emissions by 90 percent.
(4) Limit the concentration of THC (as carbon, and minus methane if
you wish to subtract methane) in the outlet of the add-on control
system to 20 parts per million by volume, dry basis (ppmvd).
(5) Limit the concentration of methanol in the exhaust from the
add-on control system to 1 ppmvd (can be used only if the concentration
of methanol entering the control device is greater than or equal to 10
ppmvd).
(6) Limit the concentration of formaldehyde in the exhaust from the
add-on control system to 1 ppmvd (can be used only if the concentration
of formaldehyde entering the control device is greater than or equal to
10 ppmvd).
In the first three options ((1) through (3)), the 90 percent
control efficiency represents a total control efficiency. Total control
efficiency is defined as the product of the capture efficiency and the
control device efficiency. For process units such as rotary strand
dryers, capture efficiency is not an issue because the rotary strand
dryer has a single exhaust point which is easily captured by the
control device. However, for presses and board coolers, the HAP
emissions cannot be completely captured without installing an
enclosure. If the enclosure meets the criteria for a wood products
enclosure as defined in Sec. 63.2292 in today's final rule, then you
would assign the enclosure a capture efficiency of 100 percent. You
must test other enclosures to determine capture efficiency using EPA
Test Methods 204 and 204A through 204F (as appropriate) found in 40 CFR
part 51, appendix M, or the alternative tracer gas procedure in
appendix A to today's final rule. For the three concentration options
((4) through (6)), you must have an enclosure that either meets the
criteria for a wood products enclosure or achieves a capture efficiency
greater than or equal to 95 percent.
The six compliance options are equivalent ways to express the HAP
control levels that represent the MACT floor. Because the compliance
options are equivalent for controlling HAP emissions, you are required
to meet only
[[Page 45950]]
one of the six compliance options for add-on control systems. However,
you must designate in your permit which one of the six options you have
selected for the affected process unit. If you plan to operate a given
process unit under different conditions, you may incorporate multiple
compliance options for the add-on control system into your permit, as
long as each separate operating condition is identified along with the
compliance option that corresponds to that operating condition.
3. Emissions Averaging Compliance Option
Emissions averaging is a means of achieving the required emissions
reductions in a less costly way. Therefore, if you operate an existing
affected source, for each process unit you could choose to comply with
the emissions averaging provisions instead of the production-based
compliance options or add-on control system compliance options.
Emissions averaging is a system of debits and credits in which the
credits must equal or exceed the debits. ``Debit-generating process
units'' are the PCWP process units that are required to meet the
control requirements but that you choose to either not control or
under-control. ``Credit-generating process units'' are the PCWP process
units that you choose to control that are not required to be controlled
under the standards. When determining your actual mass removal (AMR) of
HAP, you may include partial credits generated from debit-generating
process units that are under-controlled (e.g., you may receive credit
for 25 percent control of a debit-generating process unit). Control
devices used for credit-generating process units may not be assigned
more than 90 percent control efficiency.
Under the emissions averaging provisions, you would determine the
required mass removal (RMR) of total HAP from debit-generating process
units for a 6-month compliance period. Total HAP is defined in today's
final rule to include acetaldehyde, acrolein, formaldehyde, methanol,
phenol, and propionaldehyde. The RMR would be based on initial total
HAP measurements for each debit-generating process unit, your process
unit operating hours for a 6-month period, and the required 90 percent
control system efficiency. One hundred percent of the RMR for debit-
generating process units would have to be achieved or exceeded by the
AMR of total HAP achieved by credit-generating process units. The AMR
is determined based on initial performance tests, the total HAP removal
efficiency (not to exceed 90 percent) of the control systems used to
control the credit-generating process units, and your process unit
operating hours over the 6-month period.
There are some restrictions on use of the emissions averaging
provisions in today's final rule. You must limit emissions averaging to
the process units located within your affected source. Emissions
averaging may not be used at new affected sources. You may not include
in an emissions average those process units that are not operating or
that are shut down. Only PCWP process units using add-on control
systems may be used to generate credits.
D. What Operating Requirements Are in the Final Rule?
The operating requirements in today's final rule apply to add-on
control systems used to comply with the final rule and to process units
meeting the final production-based compliance options or emissions
averaging provisions without an add-on control device (e.g., debit-
generating process units). For incineration-based control devices and
biofilters, the final rule specifies that you must either monitor
operating parameters or use a THC continuous emission monitoring system
(CEMS) to demonstrate continuous compliance. The final operating
requirements are summarized below:
? If you operate a thermal oxidizer, such as a regenerative
thermal oxidizer (RTO), you must maintain the firebox temperature at a
level that is greater than or equal to the minimum temperature
established during the performance test. If you operate a combustion
unit that accepts process exhaust into the flame zone, you are exempt
from the testing and monitoring requirements described above for
thermal oxidizers.
? If you operate a catalytic oxidizer, such as a
regenerative catalytic oxidizer (RCO) or thermal catalytic oxidizer
(TCO), you must maintain the average catalytic oxidizer temperature at
or above the minimum temperature established during the performance
test. You must also check the activity level of a representative sample
of the catalyst at least every 12 months.
? If you operate a biofilter, you must maintain the average
biofilter bed temperature within the range you develop during the
initial performance test or during qualifying previous performance
tests using the required test methods. If you use values from previous
performance tests to establish the operating parameter ranges, you must
certify that the biofilter and associated process unit(s) have not been
modified subsequent to the date of the performance tests.
? If you operate an add-on control system not listed in
today's final rule, you must establish operating parameters to be
monitored and parameter values that represent your operating
requirements during the performance test, subject to prior written
approval by the Administrator.
? If you operate a process unit that meets the production-
based compliance options or a process unit that generates debits in an
emissions average without an add-on control device, you must maintain
on a daily basis the process unit controlling operating parameter(s)
within the ranges established during the performance test corresponding
to the representative operating conditions identified during the
performance test.
? As an alternative to monitoring the operating parameters
specified above for thermal oxidizers, catalytic oxidizers, biofilters,
other control devices, and process units that meet compliance options
without add-on control systems, you may monitor THC concentration in
the outlet stack with a THC CEMS. If you select this option, you must
maintain the outlet THC concentration below the maximum concentration
established during the performance test. You may choose to subtract
methane from the THC concentration measured by the CEMS if you wish to
do so.
E. What Are the Work Practice Requirements?
The work practice requirements in today's final rule apply to
softwood veneer dryers, dry rotary dryers, veneer redryers, hardwood
veneer dryers, and group 1 miscellaneous coating operations. For
softwood veneer dryers, the work practice requirements require you to
minimize fugitive emissions from the veneer dryer doors (by applying
appropriate operation and maintenance procedures) and from the green
end of the dryers (through proper balancing of hot zone exhausts). For
group 1 miscellaneous coating operations, the work practice
requirements specify that you must use a non-HAP coating. The work
practice requirements also specify parameters that you must monitor to
demonstrate that each dry rotary dryer, veneer redryer, and hardwood
veneer dryer continuously operates in a manner consistent with the
definitions of these process units provided in today's final rule, as
follows:
? If you operate a dry rotary dryer, you must maintain the
inlet dryer temperature at or below 600[deg]F and maintain the moisture
content of the wood particles entering the dryer at or below 30 weight
percent, on a dry basis.
[[Page 45951]]
? If you operate a veneer redryer, you must maintain the
moisture content of the wood veneer entering the dryer at or below 25
percent, by weight.
? If you operate a hardwood veneer dryer, you must process
less than 30 percent, by volume, softwood species each year.
F. When Must I Comply With the Final Rule?
Existing PCWP facilities must comply within 3 years of September
28, 2004. New sources that commence construction after January 9, 2003,
must comply immediately upon initial startup or on September 28, 2004,
whichever is later.
Existing sources that wish to be included in the delisted low-risk
subcategory must receive EPA approval of their eligibility
demonstrations no later than 3 years after September 28, 2004, or be in
compliance with the final rule. New sources that wish to be included in
the delisted low-risk subcategory must receive EPA approval of their
eligibility demonstrations no later than initial startup or on
September 28, 2004, which ever is later, or be in compliance with the
final rule.
G. How Do I Demonstrate Initial Compliance With the Final Rule?
The initial compliance requirements in today's final rule vary with
the different compliance options.
1. Production-Based Compliance Options
If you are complying with the PBCO in today's final rule, you must
conduct an initial performance test using specified test methods to
demonstrate initial compliance. You must test the efficiency of your
emissions capture device during the initial performance test if the
process unit is a press or board cooler. The actual emission rate of
the press or board cooler is equivalent to the measured emissions
divided by the capture efficiency. You must test prior to any wet
control device operated on the process unit. During the performance
test, you must identify the process unit controlling parameter(s) that
affect total HAP emissions; these parameters must coincide with the
representative operating conditions you describe in the performance
test. For each parameter, you must specify appropriate monitoring
methods and monitoring frequencies, and for continuously monitored
parameters, you must specify averaging times not to exceed 24 hours.
You must install process monitoring equipment or establish
recordkeeping procedures to be used to demonstrate compliance with the
operating requirements for the parameters you select. During the
initial performance test, you must use the process monitoring equipment
or recordkeeping procedures to establish the parameter value (e.g.,
maximum, minimum, average, or range, as appropriate) that represents
your operating requirement for the process unit. Alternatively, you may
install a THC CEMS and monitor the process unit outlet THC
concentration and establish your THC operating requirement during the
performance test.
2. Add-On Control System Compliance Options
If you use the compliance options for add-on control systems, you
must conduct an initial performance test using specified test methods
to demonstrate initial compliance. With the exception of the 20 ppmvd
THC concentration option, you must test at both the inlet and the
outlet of the HAP control device. For HAP-altering controls in
sequence, such as a wet control device followed by a thermal oxidizer,
you must test at the functional inlet of the control sequence (e.g.,
prior to the wet control device) and at the outlet of the control
sequence (e.g., thermal oxidizer outlet). If you use a wet control
device as the sole means of reducing HAP emissions, you must develop
and implement a plan to address how organic HAP captured in the
wastewater from the wet control device is contained or destroyed to
minimize re-release to the atmosphere such that the desired emission
reduction is obtained. If you use any of the six compliance options for
add-on control systems, and the process unit is a press or a board
cooler without a wood products enclosure, you must also test the
capture efficiency of your partial wood products enclosure. Prior to
the initial performance test, you must install control device parameter
monitoring equipment or THC CEMS to be used to demonstrate compliance
with the operating requirements for add-on control systems in today's
final rule. During the initial performance test, you must use the
control device parameter monitoring equipment or THC CEMS to establish
the parameter values that represent your operating requirements for the
control systems. If your add-on control system is preceded by a
particulate control device (e.g., baghouse or wet electrostatic
precipitators (WESP)), you must establish operating parameter values
for the HAP control system and not for the particulate control device.
If your control device is a biofilter, then you may use values recorded
during previous performance tests for the biofilter to establish your
operating requirements as long as you were in compliance with the
emission limits in today's final rule when the data were collected, the
test data were obtained using the test methods in today's final rule,
and no modifications were made to the process unit or biofilter
subsequent to the date of the performance tests.
3. Emissions Averaging Compliance Option
If you elect to comply with the emissions averaging compliance
option in today's final rule, you must submit an Emissions Averaging
Plan (EAP) to the Administrator for approval. The EAP must describe the
process units you are including in the emissions average. The plan also
must specify which process units will be credit-generating units
(including under-controlled, debit-generating process units that also
generate credits) and which process units will be debit-generating
units. The EAP must also include descriptions of the control systems
used to generate emission credits, documentation of the total HAP
measurements made to determine the RMR, calculations and supporting
documentation to demonstrate that the AMR will be greater than or equal
to the RMR, and a summary of the operating parameters that will be
monitored.
Following approval of your EAP, you must conduct performance tests
to determine the total HAP emissions from all process units included in
the EAP. The credit-generating process units must be equipped with add-
on control systems; therefore, for those process units, you must follow
the procedures for demonstrating initial compliance as outlined above
for add-on control systems. For debit-generating process units without
air pollution control devices (APCD), you must follow the same
procedure for establishing your operating requirements as outlined
above for process units meeting the PBCO. The emissions averaging
provisions require you to conduct all total HAP measurements and
performance test(s) when the process units are operating under
representative operating conditions. Today's final rule defines
``representative operating conditions'' as those conditions under which
the process unit will typically be operating following the compliance
date. Representative conditions include such things as using a
representative range of materials (e.g., wood material of a typical
species mix and moisture content, typical resin formulations) and
[[Page 45952]]
operating the process unit at typical operating temperature ranges.
4. Work Practice Requirements
The work practice requirements in today's final rule do not require
you to conduct any initial performance tests. To demonstrate initial
compliance with the work practice requirements for dry rotary dryers,
you must install parameter monitoring devices to continuously monitor
the dryer inlet operating temperature and the moisture content (dry
basis) of the wood furnish (i.e., wood fibers, particles, or strands
used for making board) entering the dryer. You must then use the
parameter monitoring devices to continuously monitor and record the
dryer temperature and wood furnish moisture content for a minimum of 30
days. If the monitoring data indicate that during the minimum 30-day
demonstration period, your dry rotary dryer continuously processed wood
furnish with an inlet moisture content less than or equal to 30
percent, and the dryer was continuously operated at an inlet dryer
temperature less than or equal to 600[deg]F, then your dryer meets the
definition of a dry rotary dryer in today's final rule. You must submit
the monitoring data as part of your notification of compliance status
report.
To demonstrate initial compliance with the work practice
requirements for hardwood veneer dryers, you must calculate the
annualized percentage of softwood veneer processed in the dryer by
volume, using veneer dryer production records for the 12-month period
prior to the compliance date. If the total annual percentage by volume
of softwood veneer is less than 30 percent, your veneer dryer meets the
definition of hardwood veneer dryer. You must then submit a summary of
the production data for the 12-month period and a statement verifying
that the veneer dryer will continue to process less than 30 percent
softwoods as part of your notification of compliance status report.
To demonstrate initial compliance with the work practice
requirements for softwood veneer dryers, you must develop a plan for
minimizing fugitive emissions from the veneer dryer green end and
heated zones. You must submit the plan with your notification of
compliance status report.
To demonstrate initial compliance with the work practice
requirements for veneer redryers, you must install a device that can be
used to continuously monitor the moisture content (dry basis) of veneer
entering the dryer. You must then use the moisture monitoring device to
continuously monitor and record the inlet moisture content of the
veneer for a minimum of 30 days. If the monitoring data indicate that
your veneer dryer continuously processed veneer with a moisture content
less than or equal to 25 percent during the minimum 30-day
demonstration period, then your veneer dryer meets the definition of a
veneer redryer in today's final rule. You must submit the monitoring
data as part of your notification of compliance status report.
To demonstrate initial compliance with the work practice
requirement for group 1 miscellaneous coating operations, you must
submit a signed statement with your notification of compliance status
report stating that you are using non-HAP coatings. You must also have
a record (e.g., material safety data sheets) showing that you are using
non-HAP coatings as defined in today's final rule.
H. How Do I Demonstrate Continuous Compliance With the Final Rule?
The continuous compliance requirements in today's final rule vary
with the different types of compliance options.
1. Production-Based Compliance Options
If you comply with the PBCO, then you must monitor and/or record
the controlling operating parameter(s) identified as affecting total
HAP emissions from the process unit(s) in the performance test. For
each parameter, you must use the monitoring methods, monitoring
frequencies, and averaging times (for continuously monitored parameters
not to exceed 24 hours) specified in your performance test and
Notification of Compliance Status. For each operating parameter, you
must maintain on a daily basis the parameter at or above the minimum,
at or below the maximum, or within the range (whichever applies)
established during the performance test.
Instead of monitoring process operating parameters, you may operate
a CEMS for monitoring THC concentration to demonstrate compliance with
the operating requirements in today's final rule. If you choose to
operate a THC CEMS in lieu of a continuous parameter monitoring systems
(CPMS), you must demonstrate continuous compliance, as described in the
following subsection.
2. Add-On Control System Compliance Options
For add-on control systems, you must install a CPMS to monitor the
temperature or install a CEMS to monitor THC concentration to
demonstrate compliance with the operating requirements in today's final
rule. If you operate a CPMS, you must have at least 75 percent of the
required recorded readings for each 3-hour or 24-hour block averaging
period to calculate the data averages. You must operate the CPMS at all
times the process unit is operating. You must also conduct proper
maintenance of the CPMS and maintain an inventory of necessary parts
for routine repairs of the CPMS. Using the data collected with the
CPMS, you must calculate and record the average values of each
operating parameter according to the specified averaging times.
For thermal oxidizers, you must continuously maintain the 3-hour
block average firebox temperature at or above the minimum temperature
established during the performance test. For catalytic oxidizers, you
must continuously maintain the 3-hour block average catalytic oxidizer
temperature at or above the minimum value established during the
performance test. You must also check the activity level of a
representative sample of the catalyst at least every 12 months and take
any necessary corrective action to ensure that the catalyst is
performing within its design range.
For biofilters, you must continuously maintain the 24-hour block
average biofilter bed temperature within the operating range you
establish during the performance test. You must also conduct a repeat
performance test using the applicable method(s) within 2 years
following the previous performance test and within 180 days after each
replacement of any portion of the biofilter bed with a different media
or each replacement of more than 50 percent (by volume) of the
biofilter bed media with the same type of media.
If you choose to operate a CEMS for monitoring THC concentration
instead of operating a CPMS, you must install, operate, and maintain
the CEMS according to Performance Specification 8 in 40 CFR part 60,
appendix B. You must also comply with the CEMS data quality assurance
requirements in Procedure 1 of appendix F of 40 CFR part 60. You must
conduct a performance evaluation of the CEMS according to 40 CFR 63.8
and Performance Specification 8. The CEMS must complete a minimum of
one cycle of operation (sampling, analyzing, and data recording) for
each successive 15-minute period. Using the data collected with the
CEMS, you must calculate and record the 3-hour block average THC
concentration for thermal or catalytic oxidizers. For biofilters, you
must calculate and record the 24-hour block
[[Page 45953]]
average THC concentration. You must continuously monitor and maintain
the 24-hour block average THC concentration at or below the maximum
established during the performance test. You may use a CEMS that
subtracts methane from the measured THC concentration if you wish to do so.
If you comply with today's final rule using an add-on control
system, you may request a routine control device maintenance exemption
from the Administrator. Your request for a routine control device
maintenance exemption must document the need for routine maintenance on
the control device and the time required to accomplish the maintenance,
describe the maintenance activities and the frequency of these
activities, explain why the maintenance cannot be accomplished during
process shutdowns, describe how you plan to make reasonable efforts to
minimize emissions during these maintenance activities, and provide any
other documentation required by the Administrator. If your request for
the routine control device maintenance exemption is approved by the
Administrator, it must be incorporated into your title V permit. The
compliance options and operating requirements would not apply during
times when control device maintenance covered under your approved
routine control device maintenance exemption is performed. The routine
control device maintenance exemption may not exceed 3 percent of annual
operating uptime for each green rotary dryer, tube dryer, rotary strand
dryer, or pressurized refiner controlled. The routine control device
maintenance exemption is limited to 0.5 percent of the annual operating
uptime for each softwood veneer dryer, reconstituted wood product
press, reconstituted wood product board cooler, hardboard oven, press
predryer, conveyor strand dryer, or fiberboard mat dryer controlled. If
your control device is used to control a combination of equipment with
different downtime allowances (e.g., a tube dryer and a press), then
the highest (i.e., 3 percent) downtime allowance applies.
3. Emissions Averaging Compliance Option
To demonstrate continuous compliance with the emissions averaging
provisions, you must continuously comply with the applicable operating
requirements for add-on control systems (described in the previous
subsection). You also must maintain records of your operating hours for
each process unit included in the EAP. For each semiannual compliance
period, you must demonstrate that the AMR equals or exceeds the RMR
using your initial (or most recent) total HAP measurements for debit-
generating units, initial (or most recent) performance test results for
credit-generating units, and the operating hours recorded for the
semiannual compliance period.
4. Work Practice Requirements
To demonstrate continuous compliance with the work practice
requirements for dry rotary dryers and veneer redryers, you must
operate all dry rotary dryers and veneer redryers so that they
continuously meet the definitions of these process units in today's
final rule. For dry rotary dryers, you must continuously monitor and
maintain the inlet furnish moisture content at or below 30 percent and
the inlet dryer operating temperature at or below 600[deg]F. You must
also calibrate the moisture monitor based on the procedures specified
by the moisture monitor manufacturer at least once per semiannual
compliance period to verify the readings from the moisture meter. For
veneer redryers, you must continuously monitor and maintain the inlet
veneer moisture content at or below 25 percent.
To demonstrate continuous compliance with the work practice
requirements for softwood veneer dryers, you must follow the procedures
in your operating plan for minimizing fugitive emissions from the green
end and heated zones of the veneer dryer and maintain records
documenting that you have followed your plan. For hardwood veneer
dryers, you must continue to process less than 30 percent softwood
veneer by volume and maintain records on veneer dryer production.
To demonstrate continuous compliance with the work practice
requirements for group 1 miscellaneous coating operations, you must
keep records showing that you continue to use non-HAP coatings as
defined in the final rule.
I. How Do I Demonstrate That My Affected Source Is Part of the Low-Risk
Subcategory?
For your affected source to be part of the delisted low-risk
subcategory, you must have a low-risk demonstration approved by EPA,
and you must then have federally enforceable conditions reflecting the
parameters used in your EPA-approved demonstration incorporated into
your title V permit to ensure that your affected source remains low-
risk. Low-risk demonstrations for eight facilities were conducted by
EPA, and no further demonstration is required for them. They will,
however, need to obtain title V permit terms reflecting their status.
(We will provide these sources and their title V permitting authorities
with the necessary parameters for establishing corresponding permit
terms and conditions.) These facilities are listed in Table 2 to this
preamble. Other facilities may demonstrate to EPA that their PCWP
affected source is low risk by using the look-up tables in appendix B
to 40 CFR part 63, subpart DDDD or conducting a site-specific risk
assessment as specified in appendix B to subpart DDDD. Appendix B to
subpart DDDD also specifies which process units and pollutants must be
included in your low-risk demonstration, emissions testing methods, the
criteria for determining if an affected source is low risk, risk
assessment methodology (look-up table analysis or site-specific risk
analysis), contents of the low-risk demonstration, schedule for
submitting and obtaining approval of your low-risk demonstration, and
methods for ensuring that your affected source remains in the low-risk
subcategory. If you demonstrate that your affected source is part of
the delisted low-risk subcategory of PCWP manufacturing facilities,
then your affected source is not subject to the MACT compliance
options, operating requirements, and work practice requirements in the
final PCWP rule (subpart DDDD).
1. Low-Risk Criteria
We may approve your affected source as eligible for membership in
the delisted low-risk subcategory of PCWP sources if we determine that
it is low risk for both carcinogenic and noncarcinogenic effects. To be
considered low risk, the PCWP affected source must meet the following
criteria: (1) The maximum off-site individual lifetime cancer risk at a
location where people live is less than one in one million for
carcinogenic chronic inhalation effects; (2) every maximum off-site
target-organ specific hazard index (TOSHI) (or, alternatively, an
appropriately site-specific set of hazard indices based on similar or
complementary mechanisms of action that are reasonably likely to be
additive at low dose or dose-response data for your affected source's
HAP mixture) at a location where people live is less than or equal to
1.0 for noncarcinogenic chronic inhalation effects; and (3) the maximum
off-site acute hazard quotients for acrolein and formaldehyde are less
than or equal to 1.0 for
[[Page 45954]]
noncarcinogenic acute inhalation effects. These criteria are built into
the look-up tables included in appendix B to subpart DDDD. Facilities
conducting site-specific risk assessments must explicitly demonstrate
that they meet these criteria. Facilities need not perform site-
specific multipathway human health risk assessments or ecological risk
assessments since EPA performed a source category-wide screening
assessment which demonstrates that these risks are insignificant for
all sources.
2. PCWP Affected Sources Delisted in Today's Action
Eight PCWP affected sources are being delisted today as part of the
low-risk subcategory. They are listed below in Table 2 of this
preamble. If your affected source is part of the low-risk subcategory
and you do not wish it to remain in the subcategory, you may notify us,
in writing, and we will remove your affected source from the low-risk
subcategory. Any affected sources removed from the low-risk subcategory
are subject to the requirements of subpart DDDD, as applicable. Please
address your written notification to Ms. Mary Tom Kissell (see FOR
FURTHER INFORMATION CONTACT section).
Table 2. -- Low - Risk Affected Sources in the Low-Risk PCWP Subcategory
------------------------------------------------------------------------
Name of Affected Source Location
------------------------------------------------------------------------
Georgia-Pacific Plywood Plant.......... Monroeville, AL.
Georgia-Pacific--Hawthorne Plywood Mill Hawthorne, FL.
Oregon Panel Products (Lebanite)....... Lebanon, OR.
Hardel Mutual Plywood Corporation...... Chehalis, WA.
Hood Industries, Incorporated.......... Wiggins, MS.
Plum Creek Manufacturing, LP........... Kalispell, MT.
Potlatch Corporation--St. Maries St. Maries, ID.
Plywood.
SierraPine Limited, Rocklin MDF........ Rocklin, CA.
------------------------------------------------------------------------
We performed a risk assessment to determine the magnitude of
potential chronic human cancer and noncancer risks and the potential
for acute noncancer risks and adverse environmental impacts associated
with the sources in the PCWP source category. The risk assessment was
performed for 181 of the 223 major PCWP affected sources. Affected
sources where available location data were ambiguous or where all of
their site-specific information was requested to be treated as
confidential were excluded from the analysis, leaving a total of 181
affected sources in the assessment. For the risk assessment, we used
our baseline emission estimates (developed using average emission
factors and, if available, site-specific process throughput data) and
model PCWP emissions release characteristics as inputs into our Human
Exposure Model (HEM) to generate cancer and non-cancer risk estimates
for the 181 PCWP affected sources. The risk assessment methodology is
explained in detail in the supporting information for this final rule.
Because our risk estimates include model emissions release
information, they are not as rigorous as the risk demonstrations we are
requiring PCWP affected sources to perform. Therefore, to ensure the
affected sources listed in Table 2 of this preamble meet the low risk
criteria in appendix B to subpart DDDD, we subjected them to more
stringent standards than required for risk demonstrations based on
better (i.e., site-specific) data. First, we increased the level of
protection to human health by a factor of 10. Instead of using the
criteria established in appendix B to subpart DDDD of one in 1 million
risk for cancer and TOSHI of less than or equal to 1.0, PCWP affected
sources with cancer risk greater than 0.1 in 1 million or a TOSHI
greater than 0.1 were excluded. For the remaining PCWP affected
sources, we estimated emission factors based on the highest emissions
test data we had. We remodeled these PCWP affected sources using worst-
case (i.e. highest) emission factors and the January 2004 IRIS cancer
URE for formaldehyde. From this analysis, affected sources with hazard
index values greater than 0.2 or cancer risks greater than one in 1
million were excluded. Of the remaining affected sources, we eliminated
those that are closed, have pending enforcement actions, and that did
not submit or claimed as confidential site-specific throughput data. We
also consulted with an industry trade association and they removed
various affected sources from the list for various reasons.
3. Determining HAP Emissions From the Affected Source
You must include in your low-risk demonstration every process unit
within the PCWP affected source that emits one or more of the following
HAP: acetaldehyde, acrolein, arsenic, benzene, beryllium, cadmium,
chromium, formaldehyde, lead, MDI, manganese, nickel, and phenol. You
must conduct emissions testing using the methods specified in appendix
B to subpart DDDD. For reconstituted wood product presses or
reconstituted wood product board coolers, you must determine the
capture efficiency of the capture device. If you use a control device
for purposes of demonstrating that your affected source is part of the
low-risk subcategory, then you must collect monitoring data and
establish operating limits for the control system using the same
methods specified in subpart DDDD.
4. Low-Risk Demonstrations
Once you have conducted emissions testing, you may perform a lookup
table analysis or site-specific risk analysis. Regardless of the type
of risk analysis used, you must use the most recent EPA-approved dose-
response values as posted on our Air Toxics Website at http://www.epa.gov/
ttn/atw/toxsource/summary.html to demonstrate that your
affected source may be part of the low-risk subcategory. If you can
demonstrate that your affected source is low-risk based on the look-up
table analysis, then you need not complete a site-specific risk
analysis. If your affected source is not low-risk based on the look-up
table analysis, then you may elect to proceed with site-specific risk
analysis. Appendix B to subpart DDDD specifies what your low-risk
demonstration must contain.
Look-up table analysis. You may use the look-up tables (Tables 3
and 4 to 40 CFR part 63, subpart DDDD, appendix B) to determine if your
affected source may be part of the low-risk subcategory. Table 3 to
appendix B to subpart DDDD provides the maximum allowable toxicity-
weighted carcinogen emission rate, and Table 4 to appendix B to subpart
DDDD provides the maximum allowable toxicity-weighted noncarcinogen
emission rate that your affected source can emit. To use the look-up
tables, you must determine your toxicity-weighted carcinogen and
noncarcinogen emission rates using the equations in appendix B to
subpart DDDD; the average stack height of all PCWP emission points at
your affected source; and the minimum distance from any emission point
to the nearest property boundary. If the total toxicity-weighted
carcinogen and noncarcinogen emission rates for your affected source
are less than or equal to the values in both look-up tables, then EPA
may approve your affected source as part of the low-risk subcategory of
PCWP affected sources.
Site-specific risk assessment. You may use any scientifically-
accepted peer-reviewed risk assessment methodology to demonstrate to
EPA that
[[Page 45955]]
your affected source may be low risk. An example approach to performing
a site-specific risk assessment for air toxics that may be appropriate
for your affected source can be found in the ``Air Toxics Risk
Assessment Reference Library.'' However, this approach may not be
appropriate for all affected sources, and EPA may require that any
specific affected source use an alternative approach. You may obtain a
copy of the ``Air Toxics Risk Assessment Reference Library, Volume 2,
Site-Specific Risk Assessment Technical Resource Document'' through
EPA's air toxics website at http://www.epa.gov/ttn/atw.
For EPA to approve your low-risk demonstration, you must
demonstrate that: (1) The maximum off-site individual lifetime cancer
risk at a location where people live is less than one in one million
for carcinogenic chronic inhalation effects; (2) every maximum off-site
TOSHI at a location where people live is less than or equal to 1.0 for
non-carcinogenic chronic inhalation effects; and (3) the maximum off-
site acute hazard quotients for acrolein and formaldehyde are less than
or equal to 1.0 for noncarcinogenic acute inhalation effects.
5. When Must I Submit Risk Demonstrations to EPA?
You must submit your low-risk demonstration to EPA for approval. If
you have an existing affected source, you must submit your low-risk
demonstration no later than July 31, 2006. To facilitate the review and
approval process, EPA encourages facilities to submit their assessments
as soon as possible. If you have an affected source that is an area
source that increases its emissions or its potential to emit such that
it becomes a major source of HAP before the effective date of subpart
DDDD, then you must complete and submit for EPA approval your low-risk
demonstration no later than July 31, 2006. If you have an affected
source that is an area source that increases its emissions or its
potential to emit such that it becomes a major source of HAP after the
effective date of subpart DDDD, then you must complete and submit for
approval your low-risk demonstration no later than 12 months after you
become a major source or after initial startup of your affected source
as a major source, whichever is later.
If you have a new or reconstructed affected source you must conduct
the emission tests upon initial startup and use the results of these
emissions tests to complete and submit your low-risk demonstration
within 180 days following your initial startup date. If your new or
reconstructed affected source starts up before the effective date of
subpart DDDD, for EPA to find that you are included in the low-risk
subcategory, your low-risk demonstration must show that you were
eligible for the low-risk subcategory no later than the effective date
of subpart DDDD. If your new or reconstructed source starts up after
the effective date of subpart DDDD, for EPA to find that you are
included in the low-risk subcategory, your low-risk demonstration must
show that you were eligible for the low-risk subcategory upon initial
startup of your affected source.
Affected sources that are not part of the low-risk subcategory
within 3 years after the effective date of subpart DDDD must comply
with the requirements of 40 CFR part 63, subpart DDDD. Facilities may
not request compliance extensions from the permitting authority if they
fail to demonstrate they are part of the low-risk subcategory or to
request additional time to install controls to become part of the low-
risk subcategory. All approved low risk sources must then obtain title
V permit revisions including terms and conditions reflecting the
parameters used in their approved demonstrations, according to the
schedules in their applicable part 70 or part 71 title V permit programs.
6. Remaining in the Low-Risk Subcategory
You must ensure that your affected source is low risk by
periodically certifying your affected source is low risk, monitoring
applicable HAP control device parameters, and by maintaining certain
records. You must certify with each annual title V permit compliance
certification that the basis for your affected source's low-risk
determination has not changed. Your certification must consider process
changes that increase HAP emissions, population shifts, and changes to
dose-response values. If your affected source commences operating
outside of the low-risk subcategory, it is no longer part of the low-
risk subcategory. You must notify the permitting authority as soon as
you know, or could have reasonably known, that your affected source is
or will be operating outside of the low-risk subcategory. You must be
in compliance with all of the applicable requirements of 40 CFR part
63, subpart DDDD beginning on the date when your affected source
commences operating outside the low-risk subcategory if you had a
process change that increases HAP emissions. If you are operating
outside of the low-risk subcategory due to a population shift or change
to dose-response values, then you must comply with all of the
applicable requirements of 40 CFR part 63, subpart DDDD no later than
three years from the date your affected source commences operating
outside the low-risk subcategory.
III. Summary of Environmental, Energy, and Economic Impacts
A. How Many Facilities Are Impacted by the Final Rule?
Facilities with estimated potential to emit 25 tons or more of
total HAP or 10 or more tons of an individual HAP are major sources of
HAP and are subject to the final rule. Approximately 223 PCWP major
source facilities nationwide are expected to meet the applicability
criteria defined in today's final rule. These major source facilities
generally manufacture one or more of the following products: Softwood
plywood, softwood veneer, medium density fiberboard (MDF), oriented
strandboard (OSB), particleboard, hardboard, laminated strand lumber,
and laminated veneer lumber. However, only 212 of these facilities have
equipment that is subject to the control requirements of the final
rule. In addition, there are approximately 34 major source sawmill
facilities that produce kiln-dried lumber; although these major source
sawmill facilities meet the applicability criteria in the final rule,
there are no control requirements for any of the equipment located at
the sawmills.
The number of impacted facilities was determined based on the
estimated potential to emit (i.e., uncontrolled HAP emissions) from
each facility, whether each facility has any process units subject to
the compliance options, whether or not the facility already operates
control systems necessary to meet the final rule, and whether or not
the affected source is currently eligible (or may later demonstrate
eligibility) for inclusion in the delisted low risk subcategory. Of the
223 major source facilities, an estimated 162 are expected to install
add-on control systems to reduce emissions. The remaining facilities
already have installed add-on controls, do not have any process units
subject to the compliance options, are expected to comply with work
practice requirements only, or are one of the eight facilities
currently eligible for inclusion in the delisted low-risk subcategory.
We estimate that eventually as many as 147 of the 223 major source PCWP
facilities may demonstrate eligibility for the low-risk subcategory,
leaving 58 facilities expected to install add-on control systems to
reduce emissions. Some of the 147 facilities expected to eventually
[[Page 45956]]
be included the low-risk subcategory were not expected to install
controls to meet MACT because they either already have the necessary
controls or do not have process units subject to the compliance options
in today's final rule.
The environmental and cost impacts presented in this preamble
represent the estimated impacts for the range of facilities, from 58
facilities estimated to be impacted following completion of eligibility
demonstrations for the low-risk subcategory, to 162 facilities
estimated to be impacted today. The impact estimates were based on the
use of RTO (or in some cases a combination WESP and RTO) because RTO
are the most prevalent HAP emissions control technology used in the
PCWP industry. However, technologies other than RTO could be used to
comply with today's final rule. For a facility that we feel already
achieves the emissions reductions required by today's final rule, only
testing, monitoring, reporting and recordkeeping cost impacts were estimated.
B. What Are the Air Quality Impacts?
We estimate nationwide baseline HAP emissions from the PCWP source
category to be 17,000 Mg/yr (19,000 tons/yr) at the current level of
control. We estimate that today's final rule will reduce total HAP
emissions from the PCWP source category by about 9,900 Mg/yr (11,000
tons/yr). In addition, we estimate that today's final rule will reduce
VOC emissions (approximated as THC) by about 25,000 Mg/yr (27,000 tons/
yr) from a baseline level of 45,000 Mg/yr (50,000 tons/yr). Depending
on the number of facilities eventually demonstrating eligibility for
the low-risk subcategory, these emission reductions could change to
5,900 Mg/yr (6,600 tons/yr) for HAP or 13,000 Mg/yr (14,000 tons/yr)
for VOC.
In addition to reducing emissions of HAP and VOC, today's final
rule will also reduce emissions of criteria pollutants, such as carbon
monoxide (CO) from direct-fired emission sources and particulate matter
less than 10 microns in diameter (PM10). We estimate that
today's final rule will reduce CO emissions by about 9,500 Mg/yr
(10,000 tons/yr). We also estimate that the final rule will reduce
PM10 emissions by about 11,000 Mg/yr (12,000 tons/yr).
Depending on the number of facilities eventually demonstrating
eligibility for the low-risk subcategory, these emission reductions
could change to 7,600 Mg/yr (8,400 tons/yr) for CO and 5,300 Mg/yr
(5,900 tons/yr) for PM10.
Combustion of exhaust gases in an RTO generates some emissions of
nitrogen oxides (NOX). We estimate that the nationwide
increase in NOX emissions due to the use of RTO will be
about 2,100 Mg/yr (2,400 tons/yr). This estimated increase in
NOX emissions may be an overestimate because some plants may
select control technologies other than RTO to comply with today's final
rule. Depending on the number of facilities eventually demonstrating
eligibility for the low-risk subcategory, the estimated NOX
emission increase could fall to 1,100 Mg/yr (1,200 tons/yr).
Secondary air impacts of today's final rule could result from
increased electricity usage associated with operation of control
devices. The secondary air emissions of NOX, CO,
PM10, sulfur dioxide (SO2) depend on the fuel used to
generate electricity and on other factors. The EPA believes SO2
emissions may not increase from electric generation since that the
requirements of the Acid Rain trading program will keep power plants
from increasing their SO2 emissions. Furthermore, we believe that
NOX emissions increases from power plants may be limited.
The EPA expects the emissions trading program that is part of the
NOX SIP call will likely keep NOX emissions in
the eastern United States from increasing as result of additional power
generation to operate RTOs.
C. What Are the Water Quality Impacts?
Wastewater is produced from WESP blowdown, washing out of RTO, and
biofilters. We based all of our impact estimates on the use of RTO
(with or without a WESP upstream depending on the process unit). We
estimate that the wastewater generated from WESP blowdown and RTO
washouts will increase by about 100,000 cubic meters per year (m\3\/yr)
(27 million gallons per year (gal/yr)) as a result of today's final
rule. Depending on the number of facilities eventually demonstrating
eligibility for the low-risk subcategory, the wastewater impacts could
fall to 90,000 cubic meters per year (m\3\/yr) (24 million gallons per
year (gal/yr)). According to the data in our MACT survey, this
nationwide increase in wastewater flow is within the range of water
flow rates handled by individual facilities. Facilities would likely
dispose of this wastewater by sending it to a municipal treatment
facility, reusing it onsite (e.g., in log vats or resin mix), or
hauling it offsite for spray irrigation. In addition, we are amending
the effluent limitations, guidelines for the timber products processing
point source category to allow facilities (on a case-by-case basis) to
obtain a permit to discharge wastewaters from APCD installed to comply
with today's final rule.
D. What Are the Solid Waste Impacts?
Solid waste is produced in the form of solids from WESP and by RTO
or RCO media replacement. We estimate that 4,500 Mg/yr (4,900 tons/yr)
of solid waste will be generated as a result of today's final rule.
Depending on the number of facilities eventually demonstrating
eligibility for the low-risk subcategory, the solid waste increase
could change to 2,800 Mg/yr (3,000 tons/yr). Some PCWP facilities have
been able to use RTO or RCO media as aggregate in onsite roadbeds. Some
facilities have also been able to identify a beneficial reuse for wet
control device solids (such as giving them away to local farmers for
soil amendment).
E. What Are the Energy Impacts?
The overall energy demand (i.e., electricity and natural gas) is
expected to increase by about 4.3 million gigajoules per year (GJ/yr)
(4.1 trillion British thermal units per year (Btu/yr)) nationwide under
today's final rule. The estimated increase in the energy demand is
based on the electricity requirements associated with RTO and WESP and
the fuel requirements associated with RTO. Electricity requirements are
expected to increase by about 711 gigawatt hours per year (GWh/yr)
under today's final rule. Natural gas requirements are expected to
increase by about of 44 million m\3\/yr (1.6 billion cubic feet per
year (ft\3\/yr)) under the final rule. Depending on the number of
facilities eventually demonstrating eligibility for the low-risk
subcategory, these energy estimates could fall to 2.3 million GJ/yr
(2.2 trillion Btu/yr) for overall energy demand, 378 GWh/yr for the
increase in electricity requirements, and 24 million m\3\/yr (0.9
billion ft\3\/yr) for the increase in natural gas requirements.
F. What Are the Cost Impacts?
The cost impacts estimated for today's final rule represent a high-
end estimate of costs. Although the use of RTO technology to reduce HAP
emissions represents the most expensive compliance option, we based our
nationwide cost estimates on the use of RTO technology at all of the
impacted facilities because: (1) RTO technology can be used to reduce
emissions from all types of PCWP process units; and (2) we could not
accurately predict which facilities would use emissions averaging or
PBCO or install add-on control devices that are less costly to operate,
such as RCO and biofilters. Therefore, our cost estimates are likely to be
[[Page 45957]]
overstated as we anticipate that owners and operators of impacted
sources will take advantage of available cost saving opportunities.
The high-end estimated total capital costs of today's final rule
are $471 million. Depending on the number of facilities eventually
demonstrating eligibility for the low-risk subcategory, the capital
costs could fall to $240 million. These capital costs apply to existing
sources and include the costs to purchase and install both the RTO
equipment (and in some cases, a WESP upstream of the RTO) and the
monitoring equipment, and the costs of performance tests. Wood products
enclosure costs are also included for reconstituted wood products presses.
The high-end estimated annualized costs of the final standards are
$140 million. Depending on the number of facilities eventually
demonstrating eligibility for the low-risk subcategory, the annualized
costs could fall to $74 million. The annualized costs account for the
annualized capital costs of the control and monitoring equipment,
operation and maintenance expenses, and recordkeeping and reporting
costs. Potential control device cost savings and increased
recordkeeping and reporting costs associated with the emissions
averaging provisions in today's final rule are not accounted for in
either the capital or annualized cost estimates.
G. What Are the Economic Impacts?
The economic impact analysis shows that the expected price
increases for affected output would range from 0.4 to 1.3 percent as a
result of the NESHAP for PCWP manufacturers. The expected change in
production of affected output is a reduction of 0.06 to 0.4 percent for
PCWP manufacturers as a result of today's final rule. No plant closures
are expected out of the 223 facilities affected by the final rule.
Therefore, it is likely that there is no adverse impact expected to
occur for those industries that produce output affected by the final
rule, such as hardboard, softwood plywood and veneer, engineered wood
products, and other wood composites.
H. What Are the Social Costs and Benefits?
Our assessment of costs and benefits of today's final rule is
detailed in the ``Regulatory Impact Analysis for the Proposed Plywood
and Composite Wood Products MACT.'' The Regulatory Impact Analysis
(RIA) is located in Docket number A-98-44 and Docket number OAR-2003-0048.
It is estimated that 3 years after implementation of the final rule
requirements, reductions of formaldehyde, acetaldehyde, acrolein,
methanol, phenol and several other HAP from existing PCWP emission
sources would be 5,900 Mg/yr (6,600 tons/yr) to 9,900 Mg/yr (11,000
tons/yr), depending on how many affected sources are in the low-risk
subcategory. The health effects associated with these HAP are discussed
earlier in this preamble.
At this time, we are unable to provide a comprehensive
quantification and monetization of the HAP-related benefits of the
final rule. Nevertheless, it is possible to derive rough estimates for
one of the more important benefit categories, i.e., the potential
number of cancer cases avoided and cancer risk reduced as a result of
the imposition of the MACT level of control on this source category.
Our analysis suggests that imposition of the MACT level of control
would reduce cancer cases by less than one case per year, on average,
starting some years after implementation of the standards. We present
these results in the RIA. This risk reduction estimate is uncertain and
should be regarded as an extremely rough estimate and should be viewed
in the context of the full spectrum of unquantified noncancer effects
associated with the HAP reductions.
The control technologies used to reduce the level of HAP emitted
from PCWP sources are also expected to reduce emissions of CO,
PM10, and VOC. Depending on how many affected sources are in
the low-risk subcategory, it is estimated that CO emissions reductions
total approximately 7,600 Mg/yr (8,400 tons/yr) to 9,500 Mg/yr (10,000
tons/yr), PM10 emissions reductions total approximately
5,300 Mg/yr (5,900 tons/yr) to 11,000 Mg/yr (12,000 tons/yr), and VOC
emissions reductions (approximated as THC) total approximately 13,000
Mg/yr (14,000 tons/yr) to 25,000 Mg/yr (27,000 tons/yr). These
estimated reductions occur from existing sources in operation 3 years
after the implementation of the requirements of the final rule and are
expected to continue throughout the life of the sources. Human health
effects associated with exposure to CO include cardiovascular system
and CNS effects, which are directly related to reduced oxygen content
of blood and which can result in modification of visual perception,
hearing, motor and sensorimotor performance, vigilance, and cognitive
ability. The VOC emissions reductions may lead to some reduction in
ozone concentrations in areas in which the affected sources are
located. There are both human health and welfare effects that result
from exposure to ozone, and these effects are listed in Table 3 of this
preamble.
Table 3.--Unquantified Benefit Categories From HAP, Ozone-Related, and PM Emissions Reductions
----------------------------------------------------------------------------------------------------------------
Unquantified effects Unquantified effect Unquantified effect
categories associated categories associated categories associated
with HAP with ozone with PM
----------------------------------------------------------------------------------------------------------------
Health Categories................. Carcinogenicity Airway responsiveness Premature mortality
Genotoxicity............ Pulmonary inflammation.. Chronic bronchitis
Pulmonary function Increased susceptibility Hospital admissions for
decrement. to respiratory chronic obstructive
Dermal irritation....... infection. pulmonary disease,
Eye irritation.......... Acute inflammation and pneumonia,
Neurotoxicity........... respiratory cell damage. cardiovascular
Immunotoxicity.......... Chronic respiratory diseases, and asthma
Pulmonary function damage/Premature aging Changes in pulmonary
decrement. of lungs. function
Liver effects........... Emergency room visits Morphological changes
Gastrointestinal effects for asthma. Altered host defense
Kidney effects.......... Hospital admissions for mechanisms
Cardiovascular respiratory diseases. Cancer
impairment. Asthma attacks.......... Other chronic
Hematopoietic (Blood Minor restricted respiratory disease
disorders). activity days. Emergency room visits
Reproductive/ for asthma
Developmental effects. Lower and upper
respiratory symptoms
Acute bronchitis
Shortness of breath
Minor restricted
activity days
Asthma attacks
Work loss days.
[[Page 45958]]
Welfare Categories................ Corrosion/Deterioration Ecosystem and vegetation Materials damage
Unpleasant odors........ effects in Class I Damage to ecosystems
Transportation safety areas (e.g., national (e.g., acid sulfate
concerns. parks) deposition)
Yield reductions/Foliar Damage to urban Nitrates in drinking
injury. ornamentals (e.g., water.
Biomass decrease........ grass, flowers, shrubs,
Species richness decline and trees in urban
Species diversity areas).
decline. Commercial field crops..
Community size decrease. Fruit and vegetable
Organism lifespan crops.
decrease. Reduced yields of tree
Trophic web shortening.. seedlings, commercial
and non-commercial
forests.
Damage to ecosystems....
Materials damage........
Reduced worker
productivity.
----------------------------------------------------------------------------------------------------------------
At the present time, we cannot provide a monetary estimate for the
benefits associated with the reductions in CO. We also did not provide
a monetary estimate for the benefits associated with the changes in
ozone concentrations that result from the VOC emissions reductions
since we are unable to do the necessary air quality modeling to
estimate the ozone concentration changes. For PM10 , we did
not provide a monetary estimate for the benefits associated with the
reduction of the emissions, although these reductions are likely to
have significant health benefits to populations living in the vicinity
of affected sources.
There may be increases in NOX emissions associated with
today's final rule as a result of increased use of incineration-based
controls. These NOX emission increases by themselves could
cause some increase in ozone and particulate matter (PM)
concentrations, which could lead to impacts on human health and welfare
as listed in Table 3 of this preamble. The potential impacts associated
with increases in ambient PM and ozone due to these emission increases
are discussed in the RIA. In addition to potential NOX
increases at affected sources, today's final rule may also result in
additional electricity use at affected sources due to application of
controls. As such, the final rule may result in additional health
impacts from increased ambient PM and ozone from these increased
utility emissions. We did not quantify or monetize these health impacts.
Every benefit-cost analysis examining the potential effects of a
change in environmental protection requirements is limited to some
extent by data gaps, limitations in model capabilities (such as
geographic coverage), and uncertainties in the underlying scientific
and economic studies used to configure the benefit and cost models.
Deficiencies in the scientific literature often result in the inability
to estimate changes in health and environmental effects. Deficiencies
in the economics literature often result in the inability to assign
economic values even to those health and environmental outcomes which
can be quantified. These general uncertainties in the underlying
scientific and economics literatures are discussed in detail in the RIA
and its supporting documents and references.
In determining the overall economic consequences of the final rule,
it is essential to consider not only the costs and benefits expressed
in dollar terms but also those benefits and costs that we could not
quantify. A full listing of the benefit categories that could not be
quantified or monetized in our analysis is provided in Table 3 of this
preamble.
IV. Summary of Responses To Major Comments and Changes to the Plywood
and Composite Wood Products NESHAP
We proposed the PCWP NESHAP on January 9, 2003 (68 FR 1276), and
received 57 comment letters on the proposal during the comment period.
In response to the public comments received on the proposed rule, we
made several changes in developing today's final rule. Table 4 of this
preamble provides a list of the major changes that we made to the final
rule. The major comments and our responses are summarized in the
following sections. A complete summary of the comments received during
the comment period and responses thereto can be found in the background
information document (BID) for the promulgated rule, which is available
from several sources (see SUPPLEMENTARY INFORMATION section).
Table 4.--Summary of Major Changes to Subpart DDDD of Part 63
------------------------------------------------------------------------
Proposed section Final section Change from proposal
------------------------------------------------------------------------
Sec. 63.2231................ Sec. 63.2231... Revised section to
state that subpart
DDDD does not apply
to facilities that
are part of the low-
risk subcategory of
PCWP manufacturing
facilities.
Sec. 63.2232(b)............. Sec. 63.2232(b) Description of
affected source
revised to be
consistent with
revised definition.
Sec. 63.2240................ Sec. 63.2240... Clarified application
of compliance
options to a single
process unit.
Sec. 63.2240(a)............. Sec. 63.2240(a) Added wet control
device to the list
of devices that may
not be used to meet
the PBCO.
Sec. 63.2240(b)............. Sec. 63.2240(b) Changed press
enclosure reference
from ``PTE'' to
``wood products
enclosure.''
[[Page 45959]]
Sec. 63.2240(c)(1).......... Sec. Revised definition of
63.2240(c)(1). AMR and OCEPi in
emissions averaging
calculations to
clarify that sources
can receive partial
credits from debit-
generating process
units that are
undercontrolled;
revised definition
of CDi to address
test method for
biological treatment
units that do not
meet the definition
of biofilter.
Sec. 63.2240(c)(2)(iii)..... Sec. Revised restriction
63.2240(c)(2)(ii on emissions average
i). related to process
units that are
already controlled.
Sec. 63.2241(c) Added new section
that exempts dry
rotary dryers,
hardwood veneer
dryers, and veneer
redryers from work
practice
requirements if they
comply with more
stringent standards
in Sec. 63.2240.
Sec. 63.2250(a)............. Sec. 63.2250(a) Revised section to
clarify that SSM
refers to both
process unit and
control device SSM.
Sec. 63.2250(d)............. Sec. 63.2250(a) Moved and revised
section to
consolidate
explanation of SSM
provisions.
Sec. 63.2250(d) Added specific
example of a
shutdown for direct-
fired burners and a
specific example of
a startup for direct-
fired softwood
veneer dryers.
Sec. 63.2250(e)............. ................. Removed requirement
to record control
device maintenance
schedule.
Sec. 63.2250(f)............. ................. Removed requirement
to maintain and
operate catalyst
according to
manufacturer's
specifications.
Sec. 63.2251(a)............. Sec. 63.2251(a) Added partial list of
events eligible for
a routine control
device exemption;
clarified duty to
minimize emissions.
Sec. 63.2251(b)(1).......... Sec. Specified type of
63.2251(b)(1). strand dryer
controlled by a
control device
eligible for a
routine control
device maintenance
exemption of 3
percent of annual
uptime.
Sec. 63.2251(b)(2).......... Sec. Added conveyor strand
63.2251(b)(2). dryer to list of
process units
controlled by a
control device
eligible for a
routine control
device maintenance
exemption of 0.5
percent of annual
uptime.
Sec. 63.2251(e)............. Sec. 63.2251(e) Removed requirement
to schedule control
device maintenance
at the beginning of
each semi-annual
period.
Sec. 63.2260(a)............. Sec. 63.2260(a) Expanded exemption
from testing and
monitoring
requirements to all
combustion units
that introduce
process unit exhaust
into the flame zone.
Sec. 63.2262(d)............. Sec. Added sampling
63.2262(d)(1). location
Sec. requirements for
63.2262(d)(2). control devices in
sequence, process
units with no
control device, and
process units with a
wet control device.
Sec. 63.2262(g)............. Sec. Reworded and
63.2262(g)(1). renumbered section
to allow for one
case in which non-
detect data is not
considered to be one-
half the method
detection limit.
Sec. Added exception to
63.2262(g)(2). requirement to treat
non-detect data as
one-half the
detection limit.
Sec. 63.2262(k)(1).......... Sec. Clarified
63.2262(k)(1). requirements for
establishing the
minimum firebox
temperature for
thermal oxidizers.
Sec. 63.2262(k)(2).......... ................. Removed sections on
Sec. 63.2262(k)(3).......... establishing
operating parameter
limits for static
pressure and stack
gas flow for thermal
oxidizers.
Sec. 63.2262(k)(4).......... Sec. Removed references to
63.2262(k)(2). static pressure and
gas flow rate
operating
parameters.
Sec. 63.2262(k)(5).......... Sec. Revised eligibility
63.2262(k)(3). criteria for
exemptions from
performance testing
and operating
requirements for
thermal oxidizers.
Sec. 63.2262(l)(1).......... Sec. Clarified
63.2262(l)(1). requirements for
establishing the
minimum catalytic
oxidizer
temperature.
Sec. 63.2262(l)(2).......... ................. Removed sections on
Sec. 63.2262(l)(3).......... establishing
operating parameter
limits for static
pressure and stack
gas flow for
catalytic oxidizers.
Sec. 63.2262(l)(4).......... Sec. Removed references to
63.2262(l)(2). static pressure and
gas flow rate
operating
parameters.
Sec. 63.2262(m)(1).......... Sec. Revised requirements
Sec. 63.2262(m)(2).......... 63.2262(m)(1). for establishing
Sec. biofilter operating
63.2262(m)(2). limits (temperature
range).
Sec. 63.2262(n)(1).......... Sec. Revised monitoring
63.2262(n)(1). requirements for
process units that
meet compliance
options without the
use of an add-on
control device.
Sec. 63.2267................ Sec. 63.2267... Added initial
compliance criteria
for a wood products
enclosure.
Sec. 63.2268... Added criteria for
demonstration of
initial compliance
for a wet control
device.
Sec. 63.2268(a)(1).......... Sec. Revised continuous
63.2269(a)(1). parameter monitoring
system requirements.
Sec. 63.2268(a)(3).......... Sec. 63.2270(d) Revised and moved
Sec. 63.2268(a)(4).......... Sec. 63.2270(e) sections regarding
determination of
block averages and
valid data to
section on
continuous
compliance
requirements.
Sec. 63.2268(b)(2).......... Sec. Clarified temperature
Sec. 63.2268(b)(3).......... 63.2269(b)(2). measurement
Sec. requirements.
63.2268(b)(3).
Sec. 63.2268(c)............. ................. Removed sections
Sec. 63.2268(d)............. ................. regarding pH,
Sec. 63.2268(e)............. ................. pressure, and flow
monitoring.
[[Page 45960]]
Sec. 63.2268(f)(1).......... Sec. Revised requirements
Sec. 63.2268(f)(2).......... 63.2269(c)(1). for wood moisture
Sec. monitoring.
63.2269(c)(2).
Sec. Added equation for
63.2269(c)(5). converting moisture
measurements from
wet basis to dry
basis.
Sec. 63.2270(c)............. Sec. 63.2270(c) Added language to
specify that data
recorded during
periods of SSM may
not be used in data
averages and
calculations used to
report emission or
operating levels.
Sec. 63.2270(f) Added requirement
that 75 percent of
readings recorded
and included in
block averages must
be based on valid
data.
Sec. 63.2280(f)(6).......... Sec. Revised EAP
63.2280(f)(6). submission
requirements to
include information
on debit-generating
process units.
Sec. 63.2282(e) Added requirement to
keep records of
annual catalyst
activity checks and
subsequent
corrective actions
for catalytic
oxidizers.
Sec. 63.2291................ Sec. 63.2291... Revised section to
state that EPA
retains authority to
review eligibility
demonstrations for
the low-risk
subcategory.
Sec. 63.2292... Added definitions of
``agricultural
fiber,''
``combustion unit,''
``conveyor strand
dryer,'' ``conveyor
strand dryer zone,''
``flame zone,''
``group 1
miscellaneous
coating
operations,'' ``non-
HAP coating,'' ``one-
hour period,''
``partial wood
products
enclosure,''
``primary tube
dryer,'' ``rotary
strand dryer,''
``secondary tube
dryer,'' ``wet
control device,''
and ``wood products
enclosure.''
Sec. 63.2292................ ................. Removed definitions
of ``permanent total
enclosure,'' ``plant
site,'' and ``strand
dryer.''
Sec. 63.2292................ Sec. 63.2292... Revised definitions
of ``affected
source,''
``biofilter,''
``deviation,''
``fiber,''
``fiberboard,''
``hardboard,''
``medium density
fiberboard,''
``miscellaneous
coating
operations,''
``particle,''
``particleboard,''
``plywood and
composite wood
products (PCWP)
manufacturing
facility,''
``softwood veneer
dryer,'' and
``thermal
oxidizer.''
Table 1A...................... Table 1A......... Changed ``tube
dryers'' to
``primary tube
dryers'' and added
``secondary tube
dryers''; added PBCO
limit for secondary
tube dryers; revised
PBCO limit for
reconstituted wood
product board
coolers; changed
``strand dryers'' to
``rotary strand
dryers.''
Table 1B...................... Table 1B......... Added ``rotary strand
dryers,'' ``conveyor
strand dryer zone
one (at existing
affected sources),''
and ``conveyor
strand dryer zones
one and two (at new
affected sources)''
to the list of
process units.
Table 2, Line 1............... Table 2, Line 1.. Reduced thermal
oxidizer operating
requirements to
maintaining the
average firebox
temperature above
the minimum
temperature.
Table 2, Line 2............... Table 2, Line 2.. Reduced catalytic
oxidizer operating
requirements to
maintaining the
temperature above a
minimum temperature
and checking the
activity level of a
representative
sample of the
catalyst every 12
months.
Table 2, Line 3............... Table 2, Line 3.. Reduced biofilter
operating
requirements to
maintaining the
biofilter bed
temperature within a
range.
Table 2, Line 5............... Table 2, Line 5.. Revised operating
requirements for
process units
without control
devices.
Table 3, Line 5.. Added work practice
requirements for
group 1
miscellaneous
coating operations.
Table 4, Line 9............... Table 4, Line 9.. Revised the
performance test
criteria for
reconstituted wood
product presses and
reconstituted wood
product board
coolers.
Table 4, Line 11.............. Table 4, Line 11. Revised text to
clarify that
performance test
requirements apply
to all process units
in an emissions
average plan.
Table 5, Line 7............... Table 5, Line 7.. Removed minimum heat
input capacity
criterion for
combustion units.
Table 5, Line 8.. Added criteria for
performance testing
and initial
compliance
demonstrations for
wet control devices.
Table 6, Line 5.. Added initial
compliance
demonstration for
Group 1
miscellaneous
coating operations.
Table 7, Line 1............... Table 7, Line 1.. Revised ``at or above
the maximum, at or
below the minimum''
to read ``at or
above the minimum,
at or below the
maximum.''
Table 7, Line 3.. Added continuous
compliance
requirements
(periodic testing)
for biofilters.
Table 7, Line 4.. Added continuous
compliance
requirements (annual
catalyst activity
check) for catalytic
oxidizers.
Table 7, Line 5.. Added continuous
compliance
requirements for
process units
achieving compliance
without an add-on
control device.
Table 8, Line 1............... Table 8, Line 1.. Specified block
averages of 24 hours
for moisture and
temperature
measurements for dry
rotary dryers.
Table 8, Line 4............... Table 8, Line 4.. Specified block
average of 24 hours
for moisture
measurements for
veneer dryers.
Table 8, Line 5.. Added continuous
compliance
requirements for
Group 1
miscellaneous
coating operations.
Table 10, Sec. 63.8(g)...... Table 10, Sec. Added ``rounding of
63.8(g). data'' to
description of the
General Provisions
section.
[[Page 45961]]
Appendix A to Subpart DDDD.... Appendix A to Made various
Subpart DDDD. revisions throughout
to reflect the
removal of a
permanent total
enclosure (PTE) as a
requirement for
reconstituted wood
products presses and
board coolers.
Appendix B to Added appendix B to
Subpart DDDD. specify procedure
for demonstrating
that an affected
source is part of
the low-risk
subcategory.
------------------------------------------------------------------------
A. Applicability
1. Definition of Affected Source
Comment: Several commenters requested that we clarify that the PCWP
affected source includes refining and resin preparation activities such
as mixing, formulating, blending, and chemical storage, and suggested
that boilers be excluded. The commenters wanted to ensure that onsite
resin preparation activities are specifically mentioned in and
regulated by the final PCWP rule to avoid duplicate regulation of those
activities under the Miscellaneous Organic Chemical Manufacturing
NESHAP (subpart FFFF) or the Miscellaneous Coating Manufacturing NESHAP
(subpart HHHHH). Commenters also recommended changing the proposed
definition of affected source by revising the definition of ``plant
site,'' which was used in the affected source definition at proposal.
The commenters asked that we make the definition of ``plant site''
consistent with the definition of ``major source'' as defined for title
V permitting in 40 CFR 70.2. According to the commenters, the proposed
definition of ``plant site'' expanded the definition of a source beyond
that used for title V permitting or MACT applicability in general.
Response: We agree with the commenters that changes should be made
to the definition of affected source, and the definition was adjusted
in the final rule. We added resin preparation activities to the
definition of ``affected source'' to clarify that these activities are
part of the PCWP source category and are not subject to subpart FFFF to
40 CFR part 63 or subpart HHHHH to 40 CFR part 63. Resin preparation
includes any mixing, blending, or diluting of resins used in the
manufacture of PCWP products which occurs at the PCWP manufacturing
facility. We feel this change is appropriate because the MACT analysis
for resin preparation activities was conducted under the PCWP final
rulemaking. (As explained in the proposal BID and supporting
documentation, we determined that MACT for new and existing blenders
and resin storage/mixing tanks is no emissions reductions.) Subpart
FFFF to 40 CFR part 63 and subpart HHHHH to 40 CFR part 63 exclude
activities included as part of the affected source for other source
categories. Thus, onsite resin preparation activities at a PCWP
manufacturing facility are not subject to subpart FFFF to 40 CFR part
63 or subpart HHHHH to 40 CFR part 63.
We added refiners to the definition of affected source to clarify
that these sources are part of the affected source and were part of the
MACT analysis for the PCWP source category. (For new and existing
pressurized refiners, we determined that MACT is based on the use of
incineration-based control or a biofilter, and for new and existing
atmospheric refiners, we determined that MACT is no emissions reductions.)
We removed all references to ``plant site'' from the final rule and
replaced references to ``plant site'' with the term ``facility'' to
eliminate confusion regarding which emission sources constitute the
affected source and which emission sources would be considered when
making a major source determination. The term ``plant site'' was used
only in the proposed definitions of ``affected source'' and ``plywood
and composite wood products manufacturing facility.'' Inclusion of the
term ``plant site'' in the proposed definition of affected source
unintentionally broadened the definition such that emission sources not
related to PCWP manufacturing could be construed as being part of the
affected source. For example, under the proposed definitions of
``affected source'' and ``plant site,'' if a company operated both a
PCWP manufacturing facility and a wood building products surface
coating facility at the same site, both operations might be considered
to be part of the PCWP affected source because the ``plant site'' would
encompass both operations, even though these two operations are
regulated under separate NESHAP. We removed the term ``plant site''
from the final rule to clarify that the requirements in the final rule
would only apply to the affected source, which is the PCWP
manufacturing facility. However, we note that any major source
determination would be based on total emissions from both operations
since the two operations are colocated and under common control. (See
definition of major source in the General Provisions (40 CFR part 63,
subpart A).)
We did not incorporate the commenters' suggestion to specifically
exclude boilers from the definition of ``affected source'' because it
is possible for a boiler to be subject to both the PCWP NESHAP and the
Industrial/Commercial/Institutional Boilers and Process Heaters NESHAP
(e.g., if a portion of the boiler exhaust is used to direct fire dryers
while the remaining portion of the boiler exhaust is vented to the
atmosphere). However, in most cases, combustion units would only be
subject to one MACT. The overlap between the PCWP NESHAP and the
Industrial/Commercial/Institutional Boilers and Process Heaters NESHAP
is also discussed in this preamble.
2. Process Definitions
Comment: Commenters recommended that a number of definitions
included in the proposed rule be revised to better distinguish between
particleboard, MDF and hardboard and/or to be consistent with
definitions developed by the American National Standards Institute (ANSI).
Response: We made changes to several of the proposed process-
related definitions including the definitions of particle, fiber,
hardboard, MDF, and particleboard. These minor changes incorporate some
of the wording in similar definitions used by ANSI but do not affect
the scope or applicability of the final rule. We also added a
definition of agricultural fiber recommended by commenters because the
term ``agricultural fiber'' appears in the definition of plywood and
composite wood products facility.
Comment: Several commenters requested that the proposed definition
of tube dryer be changed so that stages in multistage tube dryers would
be considered as separate tube dryers. With this change, different
control options could be applied to different dryer stages.
Response: Under the proposed definition of tube dryer, a multistage
tube dryer with more than one control
[[Page 45962]]
device and emissions point would be considered one process unit. In
developing the proposed rule, we noted that the function of tube dryers
is the same regardless of single-or multistage configuration and that
distinguishing between dryer configurations would not change the
results of the MACT floor analysis, despite the fact that the majority
of the HAP emissions exhaust from the primary stage. Therefore, we made
no distinction between single-stage and multistage tube dryers at
proposal. However, we agree with the commenters that defining the
stages of multistage tube dryers separately would allow facilities the
flexibility of choosing different compliance options for each stage of
the tube dryer, and we have included separate definitions of primary
tube dryer and secondary tube dryer in the final rule. The MACT floor
for both primary tube dryers and secondary tube dryers is the same
(e.g., 90 percent reduction in emissions), but facilities may choose
different control options for the primary and secondary tube dryers.
For example, a facility with a multistage tube dryer could use an add-
on control device to reduce emissions from the primary tube dryer only
and then use emissions averaging to offset the uncontrolled emissions
from the secondary tube dryer.
3. Lumber Kilns
Comment: We received comments from representatives of sawmills and
wood treating facilities disagreeing with the inclusion of lumber kilns
in the PCWP source category. The commenters stated that owners and
operators of kilns that are not located at a PCWP facility may be
subject to other requirements of the rule, as proposed, that do not
truly apply to them, including costly monitoring, recordkeeping, and
reporting. One commenter was concerned that the owners and operators of
non-colocated lumber kilns could find themselves in violation of the
May 15, 2002, case-by-case ``MACT Hammer'' deadline even though they
did not anticipate being included in the rule, as proposed, and thus
did not apply for the case-by-case consideration.
Response: At proposal, we broadened the PCWP source category to
include non-colocated lumber kilns (i.e., lumber kilns located at
stand-alone kiln-dried lumber manufacturing facilities or at any other
type of facility). In the preamble to the proposed rule, we noted that
if non-colocated lumber kilns were not included in the PCWP NESHAP,
then kiln-dried lumber manufacturing could be listed as a major source
category under section 112(c) of the CAA in the future, requiring a
separate CAA section 112(d) rulemaking and potentially becoming
separately subject to the provisions of section 112(g) of the CAA as
well. We felt it was reasonable to include non-colocated lumber kilns
in the PCWP source category because the design and operation of lumber
kilns are essentially the same regardless of whether the kilns are
located at a sawmill or are colocated with PCWP or other types of
manufacturing operations. At proposal, we noted that there are no
currently applicable controls at any lumber kilns and that it would be
both more efficient and expeditious to include all lumber kilns in the
MACT analysis for the final PCWP rule than to separately address them
in a rulemaking that likely would not result in meaningful emissions
reductions from lumber kilns. In addition, we noted that including all
lumber kilns in the final PCWP MACT results in placing them on a faster
schedule for purposes of future residual risk analysis under CAA
section 112(f).
In an attempt to better understand the concerns of the commenters,
we met with wood products industry representatives who requested that
lumber kilns be included in the PCWP source category and with the
commenters who disagreed that non-colocated lumber kilns should be
included in the PCWP source category. After consideration of concerns
expressed by all of the commenters on this issue, we maintain that it
is more efficient for EPA, State regulators, and lumber kiln operators
for EPA to include all lumber kilns in the final PCWP NESHAP. Because
the MACT floor determination for lumber kilns is no emission reduction
(as explained in the proposal preamble), there will not be a
significant monitoring, recordkeeping, and reporting burden for
facilities with only non-colocated lumber kilns. Only those facilities
that are major sources of HAP emissions are subject to the final PCWP
NESHAP. Facilities with non-colocated lumber kilns that are classified
as major sources of HAP must submit an initial notification form
required by the final PCWP NESHAP and the Part 1 ``MACT Hammer''
application required by section 112(j) of the CAA. We note that both of
these forms simply ask the facilities to identify themselves to EPA. We
acknowledge that operators of non-colocated lumber kilns were not aware
that they were included in the PCWP source category until the proposed
PCWP NESHAP was printed in the Federal Register on January 9, 2003, and
therefore, would not have known to submit a Part 1 application by May
15, 2002.
4. Regulated HAP
Comment: One commenter objected to the fact that the proposed rule
only set standards for six HAP. The commenter asserted that, according
to the CAA and National Lime Ass'n v. EPA, 233 F.3d 625, 633-634 (D.C.
Cir. 2000), we are required to set standards for every HAP listed in
CAA section 112(b)(1) emitted by PCWP operations, not just the ones
that are the easiest to measure. Other commenters disagreed and noted
that a requirement that EPA impose an emission standard for every
listed HAP, without regard to whether or not there are applicable
methods for reducing HAP emissions or whether the MACT floor sources
actually use such method, contradicts the plain language of the
statute. These commenters contended that the statute specifically
frames the inquiry in terms of degrees of reduction.
Response: Today's final PCWP rule contains numerical emission
limits in terms of methanol, formaldehyde, THC, or total HAP (which is
defined in the final rule as the sum of six HAP including acrolein,
acetaldehyde, formaldehyde, methanol, phenol, and propionaldehyde). The
nationwide PCWP emissions of total HAP are 18,190 tons/yr, which is 96
percent of the nationwide emissions of all HAP (19,000 tons/yr) emitted
by PCWP facilities. The six HAP that comprise total HAP are found in
emissions from all PCWP product sectors that contain major sources and
in emissions from most process units. At proposal, when we stated that
other HAP are emitted ``in low quantities that may be difficult to
measure,'' we were referring to HAP that are often emitted at levels
below test method detection limits (68 FR 1276, January 9, 2003). Our
data clearly show that these other HAP are difficult or impossible to
measure because they are either emitted in very low quantities or are
not present. Such low quantities are not detectable by the applicable
emission testing procedures (which are sensitive enough to detect HAP
at concentrations below 1 part per million (ppm)). Many of these other
HAP were detected in less than 15 percent of test runs, or for only one
type of process unit.
Based on our emissions data, we determined that methanol,
formaldehyde, THC, or total HAP are appropriate surrogates for
measuring all organic HAP measurably-emitted by the PCWP source
category. The PBCO and emissions averaging compliance options in
today's final PCWP rule are based on total HAP. Review of the emission
[[Page 45963]]
factors used to develop the emissions estimates for the PCWP source
category indicates that uncontrolled emissions of HAP (other than the
six HAP) are always lower than emissions of the six HAP for every
process unit with MACT control requirements. Thus, process units
meeting the PBCO based on total HAP also would have low emissions of
other organic HAP. The emissions averaging provisions and add-on
control device compliance options involve use of add-on APCD. The
available data show that a reduction in one predominant HAP (or THC)
correlates with a reduction in other HAP if the other HAP is present in
detectable quantities and at sufficient concentration. The data also
show that the mechanisms in RTO, RCO, and biofilters that reduce
emissions of formaldehyde and methanol reduce emissions of the
remaining HAP. In addition, an analysis of the physical properties of
the organic HAP emitted from PCWP processes indicates that nearly all
of the HAP would be combusted at normal thermal oxidizer operating
temperatures. Today's standards are based on the use of add-on control
devices because the available emissions data do not reveal any process
variables that could be manipulated (without altering the product) to
achieve a quantifiable reduction in emissions. Furthermore, nothing in
the data suggests that process variables could be manipulated in a way
that would alter the relationship between formaldehyde and methanol
reduction and reduction of other HAP. We determined that it is
appropriate for the final PCWP rule to contain compliance options in
terms of total HAP, THC, formaldehyde, or methanol because the same
measures used to reduce emissions of these pollutants also reduce
emissions of other organic HAP.
B. Overlap With Other Rules
1. Overlap With Industrial/Commercial/Institutional Boilers and Process
Heaters NESHAP
Comment: Commenters expressed support for our proposal to regulate
emissions from combustion units used to direct fire dryers and to
exclude these emissions from the requirements of the Industrial/
Commercial/Institutional Boilers and Process Heaters NESHAP. However,
the commenters expressed concern about potential NESHAP applicability
questions that could arise during short periods when the exhaust gases
from these combustion units are not exhausting through the dryers and
would bypass any controls applied to these dryers. The commenters noted
that in some of the combustion units associated with direct-fired
dryers, a small percentage of combustion gas is routed to indirect heat
exchange and then is normally and predominantly routed to direct-fired
gas flow. According to the commenters, in these hybrid units, typically
only a small fraction of combustion gas (e.g., less than 10 percent of
total capacity) is routed to indirect heat exchange for hot oil/steam
generation. This fraction of the combustion unit exhaust then generally
exhausts through the direct-fired dryers and the emissions are treated
by the add-on control device at the dryers' outlet. However, under
certain circumstances (e.g., during startups, shutdowns, emergencies,
or periods when dryers are down for maintenance but steam/thermal oil
is still needed for plant and/or press heat), some systems may exhaust
directly to the atmosphere without passing through the direct-fired
dryers and the associated control systems. The commenters recommended
that this small subset of combustion units be assigned a primary
purpose (based on the predominant allocation of British thermal units
per hour (Btu/hr) capacity and/or predominant mode of operation) and
regulated accordingly. In the above example, the commenters assumed
that the primary purpose is as a direct-fired dryer, such that the
equipment would be subject to the final PCWP MACT and not to the
Industrial/Commercial/Institutional Boilers and Process Heaters NESHAP.
Response: In considering the commenters' request, we reviewed
available information on direct-fired dryers and the associated
combustion units at PCWP facilities. The available information
indicates that there are many configurations of combustion units,
dryers, and thermal oil heaters in the PCWP industry. While some
systems have the hybrid configurations described by the commenters
whereby a portion of the combustion gas is routed to indirect heat
exchange, other systems retain all of the combustion gas within the
direct-fired system. We do not have sufficient information (and no such
information was provided by the commenters) to fully evaluate the need
for a primary purpose designation for PCWP combustion units, to
establish the percentage-of-operating-time or British thermal unit
(Btu) limits for such a primary purpose designation, or to determine
MACT for combustion units that would meet the primary purpose
designation. For example, we do not know how many combustion units are
configured to incorporate both indirect and direct heat exchange, and
for these units we do not know the amount of time or the percentage of
Btu allocation that is devoted to indirect heat exchange or the
controls used to reduce emissions during indirect heat exchange. We
expect that all of these factors vary substantially from facility to
facility for those facilities that have these hybrid combustion units.
We also lack information on the emissions reduction techniques (e.g.,
control devices) applied to combustion units associated with direct-
fired PCWP dryers that may bypass the dryers for some unknown
percentage of time. Therefore, we feel it would be inappropriate for us
to establish a primary purpose designation which could inadvertently
allow facilities to configure their systems to direct a portion of
their uncontrolled emissions to the atmosphere without these emissions'
being subject to the Industrial/Commercial/Institutional Boilers and
Process Heaters NESHAP. Also, we wish to clarify that the final PCWP
rule regulates only that portion of emissions from a combustion unit
that are routed through the direct-fired dryers. Any emissions from a
combustion unit that are not routinely through the direct-fired dryers
would be subject to the Industrial/Commercial/Institutional Boilers and
Process Heaters NESHAP. Therefore, if the emissions from a combustion
unit are split such that only a portion of the emissions are routed
through a direct-fired dryer, then the combustion unit would be subject
to both rules.
For those occasions when a facility must shut down its direct-fired
dryers but still wants to operate the combustion unit to heat oil for
the press, the facility could propose in its startup, shutdown, and
malfunction (SSM) plan to route exhaust through the thermal oil heater
(and then to the atmosphere) during these periods. The permitting
authority would then decide on a facility-specific basis if heating of
the thermal oil heater (and the associated uncontrolled emissions)
should be allowed during dryer SSM considering the amount of time that
this condition occurs, the fraction of combustion unit Btu used to heat
the thermal oil heater, and the type of control used to reduce
combustion unit emissions.
2. Overlap With Wood Building Products (WBP) NESHAP
Comment: Commenters on the proposed Wood Building Products (Surface
Coating) rule (subpart QQQQ to 40 CFR part 63) asserted that neither
asphalt-coated fiberboard nor ceiling tiles are coated with HAP-containing
[[Page 45964]]
materials and that regulating such products would be burdensome. These
commenters requested that we include asphalt coating of fiberboard and
ceiling tiles in today's final PCWP rule by including these coating
operations under the definition of miscellaneous coating operations
(for which the proposed MACT was no emissions reductions), so that
these operations would be subject to the final PCWP rule and not the
WBP rule, as proposed.
Response: In the proposed rule, we addressed overlap between the
WBP and PCWP NESHAP by including specific surface coating activities
(which occur onsite at a PCWP manufacturing facility) in the definition
of ``miscellaneous coating operations.'' Inclusion of these activities
in the definition of miscellaneous coating operations means that these
activities are subject to the final PCWP rule and not to the WBP rule,
as proposed. We made changes to the definition of miscellaneous coating
operations in today's final rule in response to the public comments we
received on the proposed WBP rule relating to asphalt-coated fiberboard
and ceiling tiles.
We evaluated the types of coatings and processes used to make
asphalt-coated fiberboard and found that only a few facilities in the
United States make these products, with varying manufacturing and
coating processes. An asphalt emulsion can be added during the
fiberboard forming process, or asphalt can be applied to the fiberboard
substrate. Information we collected on asphalt coatings suggests that
they contain no HAP. Depending on the company and the process, the
coating can be applied before or after the final dryer with the product
allowed to air dry. Ceiling tiles are usually coated using non-HAP
slurries of titanium dioxide and various clays, and no organic solvents
are used. Most of the coatings associated with these types of products
are applied during the substrate forming process (i.e., to the wet mat
being formed) or prior to the final substrate drying operation,
fiberboard coating operations (including those used in the manufacture
of asphalt-coated fiberboard and ceiling tiles). Because no HAP are
contained in the above-mentioned coatings, the coatings are applied as
part of the manufacturing process, and MACT for these coating processes
is no emissions reductions, we changed the definition of miscellaneous
coating operations to include ``application of asphalt, clay slurry, or
titanium dioxide coatings to fiberboard at the same site of fiberboard
manufacture.'' These products are not subject to the final WBP surface
coating rule.
C. Amendments to the Effluent Guidelines for Timber Products Processing
Comment: Several commenters requested that we address potential
conflicts between the PCWP rule as proposed and the effluent guidelines
for the Timber Products Processing Point Source Category. These
commenters noted that the effluent guidelines state that ``there shall
be no discharge of process wastewater pollutants into navigable
waters.'' However, according to the commenters, at the time that
statement was written, air pollution controls were not common, and EPA
was not aware of the large volumes of water that can be produced by
APCD. The commenters recommended that we address this issue by revising
the effluent guidelines at 40 CFR part 429. Specifically, these
commenters asked us to amend the definition of process wastewaters at
40 CFR part 429.11(c) so that the discharge prohibition in 40 CFR part
429 would not apply to wastewaters associated with APCD operation and
maintenance when installed to comply with the final PCWP MACT rule.
These commenters asserted that effluent limitations for these
wastewaters should be developed by permit writers on a case-by-case
basis based upon best professional judgment. These commenters noted
that the language we included in the preamble to the proposed rule
would generally accomplish this purpose with some minor changes (see 68
FR 1276, January 9, 2003). The commenters also provided rationale and
data to support their recommendation. The commenters contended that we:
(1) Underestimated the volume of wastewater that would be generated by
the application of MACT and as a result, underestimated the associated
costs of disposing of this wastewater; (2) failed to address the
achievability/feasibility of MACT if the discharge of air pollution
control wastewaters is prohibited; and (3) did not consider wastewater
from air pollution control devices when the Timber Products zero
discharge effluent guidelines were originally developed. The commenters
submitted several case studies to demonstrate the variability in the
volume of wastewater generated at various PCWP facilities and to show
how each facility currently recycles, reuses, and disposes of
wastewater generated from the operation and maintenance of RTO, WESP
and biofilters. The commenters also argued that the available data do
not support a conclusion that wastewaters generated from MACT control
devices can, with Best Available Technology (BAT), be managed in a way
that does not involve a discharge.
Response: At the time we proposed the PCWP rule, we indicated that
we would consider amending the definition of process wastewater in 40
CFR part 429 to exclude those wastewaters generated by APCD operation
and maintenance when installed to comply with the proposed PCWP NESHAP.
We indicated in the preamble to the proposal that we would amend the
definition of process wastewaters if information and data were
submitted to support the industry's assertions that PCWP facilities in
certain subcategories would not be able consistently to achieve the
effluent limitations guidelines and standards applicable to them if
they were to comply with the proposed PCWP NESHAP. As part of the PCWP
proposal, we described with specificity how we would revise 40 CFR part
429 if we were convinced that such revisions were appropriate and
solicited data and information.
Based on the data and information submitted by the commenters, we
have concluded that facilities subject to 40 CFR part 429, subpart B
(Veneer subcategory), subpart C (Plywood subcategory), subpart D (Dry
Process Hardboard subcategory), and subpart M (Particleboard
Manufacturing subcategory) are unable to comply consistently with the
existing 40 CFR part 429 effluent limitations guidelines and standards,
which prohibit the discharge of process wastewater pollutants, because
of the volume of wastewaters generated by APCD that are installed to
comply with the final PCWP NESHAP and because the technology basis for
those effluent limitations guidelines and standards is insufficient, in
light of that wastewater volume and the pollutant content, to achieve
the prohibition on process wastewater discharges for these NESHAP-
related APCD wastewaters. Therefore, we are excluding from the
definition of process wastewaters in 40 CFR 29.11(c) the following
wastewaters associated with APCD used by PCWP facilities covered by
subparts B, C, D, and M to comply with 40 CFR 63.22: wastewater from
washout of thermal oxidizers and catalytic oxidizers, wastewater from
biofilters, and wastewater from WESP used upstream of thermal oxidizers
or catalytic oxidizers.
In addition, we agree with comments that we will need considerably
more data and information to promulgate new effluent limitations
guidelines and standards for the process wastewaters at issue today. In
particular, we will need
[[Page 45965]]
information to adequately characterize the quantity and quality of
wastewater that would be generated as result of compliance with the
MACT standards. The volume and pollutant content of wastewater
generated at these facilities are related to production processes, air
pollution control equipment that generate wastewater, the extent of
opportunities for internal recycling of wastewater, and the
availability of other process uses for wastewater. Until we promulgate
effluent limitations guidelines and standards for pollutants in these
process wastewaters, Best Practicable Technology (BPT) and BAT effluent
limitations should be established on a case-by-case basis under 40 CFR
125.3. Thus, individual facilities seeking a discharge permit will have
the opportunity, on a case-by-case basis, to characterize and obtain
discharge allowances for their wastewaters from APCD installed to
comply with the final PCWP NESHAP. The permit writer would be expected
to determine, based upon best professional judgment (BPJ), the
appropriate effluent limitations for these APCD wastewaters. (See 40
CFR 125.3.) The permit writer can take into account facility-specific
information on wastewater volumes and pollutants, available wastewater
control and treatment technologies, costs and effluent reduction
benefits, receiving water quality, and any applicable State water
quality standards. At a later date, we expect to consider whether to
amend the existing effluent limitations guidelines and standards for
the Timber Processing Industry to cover these process wastewaters. Such
an effort would involve gathering and analyzing the information and
data necessary to establish revised categorical effluent limitations
affecting subparts B, C, D, and M of 40 CFR part 429 for these APCD
wastewaters generated in complying with the final PCWP NESHAP.
Today's amendment to the final rule is based on regulatory language
included in the preamble accompanying the proposed NESHAP for PCWP
facilities (68 FR 1276, January 9, 2003). The preamble described the
relationship of the proposed MACT rule to the amendment to 40 CFR part
429 under consideration. The preamble explained that the entities
affected by the proposed MACT rule would also be affected by the
proposed amendment to 40 CFR part 429; presented both the terms and
substance of the amendment under consideration; and described the
subjects and issues involved. In addition, we solicited comments on
whether to amend 40 CFR 429.11(c) and information relevant to that
decision. While at that time we indicated that we were considering
employing a direct final rule to promulgate any such amendment, we have
concluded with support from commenters that that procedure was
unnecessary and instead are taking final action on the amendment today
without further process.
D. Existing Source MACT
1. OSB Strand Dryers
Comment: One commenter requested that further consideration be
given to the emission standards for low-temperature OSB conveyor strand
dryers. The commenter stated that because these conveyor strand dryers
emit less HAP than rotary strand dryers and have been recognized as
best available control technology (BACT) in Minnesota, they should be
exempted from control requirements in the final PCWP rule. The
commenter noted that the 12 conveyor strand dryers used by their
company have three drying zones, each with its own heating system and
exhaust vent(s). When drying hardwoods, no VOC control is required;
however, when drying pine the company controls emissions from zones 1
and 2. Zone 3 serves as a final conditioning zone and is exhausted to
the atmosphere without need for VOC control. The proposed PCWP rule
would have required the sum of the emissions from all three zones to be
reduced to MACT levels (e.g., 90 percent reduction).
Response: The MACT analysis we conducted at proposal treated
conveyor strand dryers as a separate equipment group from rotary strand
dryers. We noted that rotary strand dryers operate at much higher inlet
temperatures (e.g., often greater than or equal to 900[deg]F) than
conveyor strand dryers (e.g., typically less than 400[deg]F) and that
rotary dryers provide greater agitation of the wood strands than
conveyor strand dryers. As a result, the emissions from conveyor strand
dryers are lower than the emissions from rotary strand dryers. The
emissions test data we have for conveyor strand dryers (only
formaldehyde and THC data are available) indicate that formaldehyde
emissions from conveyor strand dryers are 1 to 2 orders of magnitude
lower than for rotary strand dryers. The THC emissions are also lower
for conveyor strand dryers than for rotary dryers. Our MACT analysis
for conveyor strand dryers at proposal concluded that three of the
eight conveyor strand dryers used in the U.S. operated with process
incineration. Because there are less than 30 conveyor strand dryers,
the MACT floor was based on the control level achieved by the third
best-controlled dryer. Thus, at proposal, we determined that the MACT
floor control system for new and existing conveyor strand dryers was
the emissions reductions achievable with incineration-based control. We
included one definition of ``strand dryers'' in the proposed PCWP rule
since MACT for both rotary and conveyor strand dryers was represented
by incineration-based control.
As pointed out by the commenter, conveyor strand dryers have
distinct zones, with each zone having its own heating system and
exhaust. We reviewed our MACT survey data and learned that all of the
conveyor strand dryers in the U.S. have three zones. Upon further
scrutiny of the MACT analysis at proposal, we learned that the three
conveyor strand dryers that formed the basis for the MACT floor at
proposal were routing the emissions from zone 1 only to an onsite
combustion unit for incineration. The remaining five conveyor strand
dryers have no HAP control. Thus, our conclusions regarding the MACT
floor for conveyor strand dryers at proposal were overstated. The third
best-controlled conveyor strand dryer has incineration-based control
only on zone 1 as opposed to controls on all zones. Therefore, we
revised our analysis to reflect that the MACT floor for existing
conveyor strand dryers is the emissions reduction achievable with
incineration-based control on zone 1. To implement this change, we
added definitions for ``conveyor strand dryer'' and ``conveyor strand
dryer zone'' to the final rule.
The commenter mentioned operating 12 conveyor strand dryers. Six of
these conveyor strand dryers are located at new plants that were not
included in our pre-proposal MACT floor analysis. These six conveyor
strand dryers route emissions from zones 1 and 2 to a closed-loop
incineration system for emissions control. Given that newer facilities
are incinerating conveyor strand dryer exhaust from zones 1 and 2, we
determined that the MACT floor for conveyor strand dryers at new
sources is the emissions reductions achievable with incineration-based
control for exhausts from zones 1 and 2.
As described in the promulgation BID and supporting documentation,
we determined that the environmental benefit of controlling additional
conveyor dryer zones would not justify the cost for existing or new
conveyor strand dryers.
[[Page 45966]]
2. Wood Products Press Enclosures
Comment: Many commenters argued that EPA Method 204 compliance
should not be a part of the PCWP MACT floor for presses because most of
the press enclosures that were described in the industry survey data as
having permanent total enclosures (PTE) were never certified by Method
204 criteria. The commenters noted that most of these enclosures were
designed according to Method 204 design criteria; however, the permits
for these facilities never required them to comply fully with Method
204 certification. The commenters contended that, of the 26 presses
identified as having PTE, only 2 had actually undergone Method 204
certification.
The commenters also argued that Method 204 cannot be applied
practically to the hot presses that are used at PCWP facilities. The
commenters stated that Method 204 was developed for applications where
the emissions have consistent properties; however, the temperature and
density of emissions from a typical multiple-opening batch wood
products press are constantly changing as the press opens and closes,
which creates layers of gases with different physical properties within
the enclosure. According to the commenters, instead of mixing and
exiting the enclosure, the layers of gases can accumulate. The layers
of gas in the upper region of the enclosure have a higher temperature
and pressure than the air outside the press, and the lower layers of
gas have a lower temperature and pressure than the air outside the
press. The commenters maintained that to force the gases outside the
enclosure, the operator would have to increase the airflow through the
system to a rate that is three to four times higher than would be
necessary for an enclosure operating at a homogenous temperature and
pressure. The commenters contended that, while many of the wood
products presses were designed to follow the Method 204 design
criteria, they were not designed to overcome this phenomenon and may
not be able to certify that all of the emissions are captured and
contained.
The commenters recommended that we address the press capture
efficiency issue by implementing work practice requirements for
enclosures. The commenters suggested that we replace the proposed
definition of PTE with a definition that includes four of the five
design criteria found in EPA Method 204, and replaces the requirement
that ``all VOC emissions must be captured and contained for discharge
through a control device'' with a requirement that ``fugitive emissions
shall be minimized through appropriate operation and maintenance
procedures applied to the PTE system.''
Response: At proposal, we stated that the MACT floor determination
for reconstituted wood products presses was based, in part, on the
assumption that a sufficient number of these presses had enclosures
that had been certified as PTE according to EPA Method 204. Presses
equipped with Method 204 certified PTE would be allowed to claim 100
percent capture efficiency, and thus, the rule requirements (e.g., 90
percent emissions reductions) would effectively apply only to the
captured emissions.
Based on our review of available permit information, we agree with
the commenters' assessment that few permits have required full Method
204 certification for reconstituted wood products press enclosures,
even though many of these press enclosures were constructed based on
the Method 204 design criteria. We also agree that the nature of the
batch pressing operations in the PCWP industry can make Method 204
certification difficult. Unlike in the printing and publishing
industry, for which Method 204 was originally developed, batch PCWP
presses are heated, cyclical operations. Because of the internal
pressurization within PCWP press enclosures, small amounts of fugitive
emissions may appear around the outside of these enclosures. The
percentage of press emissions that may be escaping from some of these
enclosures has not been quantified but is expected to be small based on
available information. We understand the commenters' concern that, due
to the presence of these small amounts of fugitive emissions,
facilities cannot certify that their Method 204 designed press
enclosure can achieve all the Method 204 criteria, in particular the
criteria in Method 204 section 6.2 which states that ``All VOC
emissions must be captured and contained for discharge through a
control device.'' While we feel that PCWP press enclosures should be
designed to capture emissions under normal operating conditions, we do
not feel it is necessary for PCWP facilities to increase the flow rate
from their press enclosures (and the size of their APCD) three to four
times to overcome the pressurization within the press enclosure. For
the PCWP industry, we feel it would be particularly inappropriate to
require such a large increase in exhaust flow to the APCD because the
exhaust flows from PCWP process equipment, including presses, are
already high volume, low concentration emission streams. High volume,
low concentration exhaust streams generally are more costly to treat
than low volume, high concentration emission streams. The best-
performing press enclosures that defined the MACT floor surround heated
presses and are all expected to have pressurization within the press
enclosure. In addition, we note that board cooler exhaust is sometimes
directed into press enclosures and that enclosures around board coolers
have not been certified according to EPA Method 204.
Therefore, instead of requiring EPA Method 204 certification of
PCWP press and board cooler enclosures as proposed, today's final rule
sets forth slightly different criteria for press and board cooler
enclosures. These criteria are based on the design criteria for PTE
included in EPA Method 204, as recommended by the commenters; however,
the criterion to capture and contain all VOC emissions has been
replaced with a requirement that the enclosure be ``designed and
maintained to capture all emissions for discharge through a control
device.'' To effect this change, we removed references to PTE in the
final rule and replaced the proposed definition of PTE with a new
definition of ``wood products enclosure'' that lists the design
criteria that must be met to comply with MACT. Enclosures that meet the
definition of wood products enclosure do not have to test to determine
the capture efficiency of these enclosures, but can assume 100 percent
capture, such that the control requirements (e.g., 90 percent
reduction) apply only to the captured emissions (i.e., the small amount
of fugitive emissions outside the enclosure is disregarded).
We also replaced the proposed definition of ``partial enclosure''
with a slightly revised definition of ``partial wood products
enclosure'' to eliminate any references to PTE in the final rule.
Because the capture efficiency of partial wood products enclosures is
unknown, today's final rule requires facilities to test the capture
efficiency of partial wood products enclosures using EPA Methods 204
and 204A-F (as appropriate), or using the alternative tracer gas
procedure included in appendix A to subpart DDDD of 40 CFR part 63. In
addition, facilities have the option of using other methods for
determining capture efficiency subject to the approval of the
Administrator. As was proposed and suggested by the commenters, today's
final rule requires facilities using partial wood products enclosures
to demonstrate a combined 90 percent capture and control efficiency for
those facilities showing
[[Page 45967]]
compliance with the percent reduction requirements for APCD. If the
partial wood products enclosure does not achieve high capture
efficiency, then facilities must offset the needed capture efficiency
by achieving a higher destruction efficiency or with emissions
averaging (with the press being an under-controlled process unit).
Comment: One commenter objected to the proposed MACT floor for
continuous presses and questioned the applicability of EPA Method 204
to continuous presses. The commenter requested that we divide
continuous and batch presses into two different process unit groups for
the purpose of determining the MACT floor. The commenter provided
information from environmental engineering firms and press
manufacturers regarding the fundamental differences between the two
types of presses. The commenter noted that continuous presses are much
longer than batch presses, reaching lengths of 200 feet (ft), which
makes them difficult to completely enclose. The commenter was unaware
of any continuous presses that have Method 204 certified PTE. The
commenter stated that enclosing a continuous press would cause
operational problems, such as heat build-up and impaired visibility,
which can lead to mechanical failures and unscheduled downtime. The
commenter also cited potential safety concerns, such as increased fire
risk and the possibility of unhealthy levels of HAP trapped inside the
enclosure. The commenter further noted that the capital and operating
costs of PTE applied to continuous presses would exceed those
associated with batch presses due to the large size of the enclosure
and the increased maintenance costs resulting from heat build-up within
the enclosure. In addition, the commenter provided VOC emissions data
based on measurements made at different points along the length of one
of their continuous presses to demonstrate that emissions from the
front stages are minimal and that the majority of emissions are from
the last 40 percent of the press length, referred to as the
``decompression zone.'' The commenter contended that gathering the
emissions from all stages of the continuous press will result in a more
dilute stream, which will be less cost-effective to treat, and that the
large volume of exhaust to be treated would likely preclude the use of
biofilters, which are more practical for treating smaller volumes of air.
To remedy the situation, the commenter recommended that we divide
batch and continuous presses into two different process unit groups for
the purpose of determining the MACT floor. Because there are fewer than
30 continuous presses, the MACT floor for existing continuous presses
would be determined based on the average emissions limitation achieved
by the five best-performing continuous presses. The commenter provided
information to support the commenter's contention that none of the
continuous presses achieved 100 percent capture and suggested that the
MACT floor for capture efficiency is 80 percent capture of emissions
from the decompression stages.
Response: As explained in the proposal preamble, we based the MACT
floor determinations for PCWP equipment on process units that are
similar with respect to design, operation, and emissions. We
acknowledge that continuous presses have a different design than
multiopening batch presses. However, continuous presses have emissions
that are within the same range as those from batch presses on a lb/MSF
of board basis. Therefore, we feel it is reasonable to group batch and
continuous presses together for purposes of determining the MACT floor.
The MACT floor for continuous presses would be the same as the MACT
floor for batch presses regardless of whether batch and continuous
presses were placed in separate equipment groups. As explained below,
we disagree that the MACT floor capture efficiency for continuous
presses is 80 percent, as suggested by the commenter.
The commenter was incorrect in suggesting that there are no
continuous presses with Method 204 certified PTE. The two existing
press enclosures in the PCWP industry identified as being Method 204
certified surround continuous presses. The lengths of these two
continuous presses are 41.5 ft and 110 ft. Due to the presence of these
presses plus additional continuous presses equipped with total
enclosures not certified via Method 204, the MACT floor for new and
existing continuous presses is still a total enclosure and
incineration-based control or biofilter, regardless of whether or not
batch and continuous presses are treated as separate equipment groups.
In addition, there is a Method 204 certified PTE around a 181-ft
continuous press at a newer PCWP facility (which was not included in
original data collection efforts and the pre-proposal MACT floor
determination); however, this press has had some operational problems
associated with its PTE. It is not clear if the operational problems
experienced by this 181-ft-long press are the result of poor PTE design
or inherent technical difficulties associated with enclosing long
continuous PCWP presses.
Long continuous presses are generally being installed at new PCWP
facilities, as opposed to being retrofit at existing facilities. Given
that there is at least one long continuous press (110 ft) with a Method
204 certified PTE that has not experienced operational problems with
its press enclosure, we feel that wood products enclosures (as defined
in today's final rule) can be designed around long continuous presses.
We recognize that higher cost may be associated with wood products
enclosures around long continuous presses than for batch presses, but
the CAA does not allow us to consider cost at the MACT floor control level.
We note that enclosures greater than 200 ft in length are common in
the printing/publishing industry. However, we do recognize there are
differences in the enclosures used in the printing/publishing industry
and those in the PCWP industry. Although not cyclical in operation like
batch presses, continuous presses are heated operations and may also
have internal pressurization issues similar to those raised by the
commenters for batch presses. Therefore, we feel it is appropriate for
the same definition of wood products enclosure promulgated for batch
presses to apply to long continuous presses as well (as opposed to
Method 204 certification).
3. MACT Floor Determinations of No Emissions Reductions
Comment: Industry commenters supported our proposed MACT floor
determinations of no emissions reductions for some process units,
arguing our approach was fully consistent with applicable case law in
the U.S. Court of Appeals for the D.C. Circuit. EPA properly determined
that the average of the best-performing 12 percent of certain existing
PCWP process units did not reflect the use of any control technology,
and that no other universally applicable variables would affect HAP
emissions, industry commenters stated. The commenters also claimed that
EPA looked at pollution prevention (P2) measures and other approaches
to determining the MACT floor, found none that are universally
applicable, and therefore was permitted to base a no emissions
reduction floor on the PCWP record.
Response: As explained in the proposal preamble and supporting
documentation, for those process units not required to meet the control
requirements in the PCWP rule as proposed, we determined that: (1) the
MACT floor level of control is no
[[Page 45968]]
emissions reductions, and beyond-the-floor control options are too
costly to be feasible; or (2) insufficient information is available to
conclude that the MACT floor level of control is represented by any
emissions reductions. We based our MACT floor determinations for PCWP
emission sources on the presence or absence of an add-on air pollution
control device because we are not aware of any demonstrated P2
techniques that can be universally applied across the industry, and we
have no information on the degree of emissions reduction that can be
achieved through P2 measures. Therefore, to our knowledge the use of
add-on controls is the only way in which PCWP sources can currently
limit HAP emissions, and the only way to identify the MACT floor for
these sources is to identify a level that corresponds to that achieved
by the use of add-on controls. When determining the MACT floor, we
ranked the process units by control device rather than by actual unit-
specific emissions reductions because we have limited inlet/outlet
emissions data. Based on the available information, we are not aware of
any significant design or operational differences among each type of
control system evaluated that would affect the ranking of process
units. Furthermore, we are not aware of factors other than the type of
control system used that would significantly affect the ranking of
process units. An analysis of the available emissions data does not
reveal any process variables that can be manipulated (without altering
the product) to achieve a quantifiable reduction in emissions. Ranking
process units according to control device, we determined that the MACT
floor is no emissions reductions for several process unit groups
including press predryers, fiberboard mat dryers, and board coolers at
existing affected sources; and dry rotary dryers, veneer redryers,
softwood plywood presses, hardwood plywood presses, engineered wood
products presses, hardwood veneer dryers, humidifiers, atmospheric
refiners, formers, blenders, rotary agricultural fiber dryers,
agricultural fiber board presses, sanders, saws, fiber washers,
chippers, log vats, lumber kilns, storage tanks, wastewater operations,
miscellaneous coating operations, and stand-alone digesters at new and
existing affected sources. As explained in the promulgation BID and
supporting documentation, we also determined that beyond-the-floor
control options are too costly for these process unit groups.
At proposal, we requested comment on whether no emissions
reductions for miscellaneous coating operations and for wastewater
operations is appropriate (68 FR 1276, January 9, 2003). We also
requested that commenters on this issue submit any information they
might have on HAP or VOC emissions from miscellaneous coating
operations and wastewater operations. However, no additional
information on these operations was received from any of the commenters
on the proposed rule. Following proposal, we reviewed our MACT analyses
for miscellaneous coating and wastewater operations, as described in
the following paragraphs and in the promulgation BID and supporting
documentation. For miscellaneous coating operations, we gathered some
additional information and were able to revise our conclusions
regarding MACT in the absence of specific information on the emissions
reduction achieved. However, we have no more reason to feel now than we
did at proposal that PCWP wastewater operations are in fact subject to
any emission control measures.
Based on the available information, we have no basis to conclude
that the MACT floor for new or existing sources is represented by any
emission reductions for several of miscellaneous coating processes
(i.e., anti-skid coatings, primers, wood patches applied to plywood,
concrete forming oil, veneer composing, and fire retardants applied
during forming), and we determined that there are no cost-effective
beyond-the-floor measures to reduce HAP from these coating processes.
However, some facilities reported use of water-based (non-HAP) coatings
in their MACT survey responses for other types of coatings (including
edge seals, nail lines, logo paint, shelving edge fillers, and
trademark/gradestamp inks). Other facilities reported use of solvent-
based coatings for these processes. In some instances, a few
respondents provided information on the percent HAP content of a
solvent-based coating. Solvent-based coatings do not always contain HAP
(e.g., the solvent may be mineral oil which does not contain HAP), and
water-based coatings typically do not contain HAP. Thus, many of the
coatings reported in the MACT survey responses are non-HAP coatings.
While the emission reduction achieved as a result of coating
substitutions cannot be determined, it is clear that use of non-HAP
coatings represents the MACT floor because of the large number of
facilities reporting use of non-HAP coatings. Beyond-the-floor options
were not considered for edge seals, nail lines, logo paint, shelving
edge fillers, and trademark/gradestamp inks because no further
emissions reductions can be achieved than through use of non-HAP
coatings. Based upon our revised MACT analysis, the final PCWP rule
requires use of non-HAP coating for processes identified as group 1
miscellaneous coating processes.
The definition of non-HAP coating included in the final rule was
based on the description of non-HAP coatings in the final WBP NESHAP
(subpart QQQQ to 40 CFR part 63). This definition allows for
unavoidable trace amounts of HAP that may be contained in the raw
materials used to produce certain coatings. Through the definition of
group 1 miscellaneous coatings in the final rule, kiln-dried lumber is
excluded from the requirement to use non-HAP coatings because
application of coatings used at kiln-dried lumber manufacturing
facilities is not part of the PCWP source category. Although
trademarks/gradestamps are applied to kiln-dried lumber, lumber kilns
are the only processes at kiln-dried lumber manufacturing facilities
covered under the PCWP source category.
For wastewater operations, we concluded that we had insufficient
information to conclude that the MACT floor level of control is
represented by any emissions reductions. The available information on
wastewater operations collected as part of the MACT survey of the PCWP
industry and information contained in State permits indicated that
these sources of emissions were not the subject of control requirements
and were not expected to be significant sources of HAP or VOC
emissions. As stated above, we received no comments containing
additional information on emissions reduction measures or HAP/VOC
emissions from wastewater operations. Thus, we have no more reason to
feel now than we did at proposal that PCWP wastewater operations are in
fact subject to any control measures. As a result, since no information
shows that these PCWP operations use add-on controls, there is no
identifiable numerical emissions level that would correspond to a MACT
floor level reflecting the use of controls, and the only floor level
demonstrable based on current data is no emissions reduction.
Furthermore, given that our best data show that the emissions from
wastewater operations are less than 1 ton/yr, we concluded that
application of the control measures mentioned above would not be cost
effective beyond-the-floor options. In response to the commenter's
objection to the incompleteness of the data set for these PCWP
operations, we note that the D.C. Circuit does not require EPA to
obtain complete data as long as we are able to otherwise estimate the
MACT floor
[[Page 45969]]
(Sierra Club v. EPA, 167 F.3d 658,662 (D.C. Cir. 1999)). Unlike dryers
and presses at PCWP plants, wastewater operations have not been
subjected by permitting authorities to controls for HAP emissions. We
expended much effort in the early stages of the project gathering
complete and accurate information on the PCWP processes with the most
potential for HAP emissions and the greatest potential for emission
control (i.e., the processes that have been the focus of permit
requirements limiting HAP/VOC emissions) and the final PCWP rule
addresses emissions from these process units.
Had we been given reason to feel that there were emissions control
measures associated with wastewater operations, we would have gathered
more information for these processes earlier in the project. Even
though we have determined that the current MACT floor for these PCWP
operations is no emission reduction, since available information
indicates they are not controlled, the HAP emissions from wastewater
operations (and other PCWP sources with MACT determinations reflecting
no emissions reductions) will be considered further when we review
residual risk as required under section 112(f).
E. New Source MACT
Comment: One commenter objected to our determination that MACT is
the same degree of control for new and existing sources for many
process units based on the fact that the best technology is the same
for new and existing sources (i.e., incineration-based controls or
biofilters). The commenter pointed out that, according to the proposal
BID, the maximum percent control efficiency is in the upper 90s for
THC, formaldehyde, and methanol. The commenter noted that the CAA
requires the MACT floor to be based on the degree of emissions
reduction achieved in practice by the best-controlled similar source.
Thus, the commenter requested that we revise the new source MACT
requirements for process units based upon the greatest reductions recorded.
Response: As explained in the preamble to the proposed rule and
supporting documentation, the MACT floor for both new and existing
sources is based on the estimate of the performance achieved through
application of RTO, RCO, or biofilters. We acknowledge that some
incineration-based controls and biofilters can achieve greater than 90
percent reduction in HAP or THC during a single performance test or a
test run within a performance test. However, we also recognize that the
percent reduction achieved can vary according to pollutant inlet
concentration, a factor that is not directly controllable from a
process or control device standpoint. Other unknown factors may also
cause variability in control system performance. For example, we have
THC percent reduction data for an RTO used to control emissions from
three tube dryers and a press at an MDF plant for two emission tests
conducted at different times. In 1996, the RTO achieved 92.7 percent
reduction of THC, and in 1998 the same RTO achieved 98.9 percent
reduction of THC. In addition, we have emissions test data for the same
process unit and control system for multiple years, and these data show
different emission factors, indicating that variability is inherent
within each process unit and control system combination. Thus, we
estimate that the best MACT technology achieves 90 percent HAP
reductions when variations in operations and measurements are considered.
F. Definition of Control Device
Comment: Several commenters requested that we add scrubbers and
adsorbers to the proposed definition of ``control device'' and that
condensers be omitted from the definition. One of the commenters
operates a particleboard press that is equipped with a condenser that
condenses steam from the press exhaust and then routes the condensate
to an onsite wastewater treatment system. The remaining noncondensed
gases are combusted in an onsite boiler as supplemental fuel. This
commenter would like to be able to comply with the PBCO for
reconstituted wood products presses rather than demonstrate compliance
with one of the add-on control system compliance options (e.g., 90
percent emissions reduction) or emissions averaging provisions;
however, the commenter noted that PBCO only apply to uncontrolled
emission sources. Therefore, the commenter requested that the
definition of control device be limited only to those add-on control
systems that were designed with HAP removal as the primary goal.
Response: We disagree with the commenters that the proposed
definition of control device should be changed. The definition in the
final rule does not include scrubbers or absorbers but does include
condensers and combustion units that incinerate process unit exhausts.
For purposes of MACT standards development, the reason a control device
is installed is immaterial. All control devices or techniques that
reduce HAP emissions are considered when setting MACT standards. We
note that the PBCO were developed and included in the PCWP rule for
inherently low-emitting process units or process units with P2
techniques and not for process units with add-on control systems.
Therefore, the particleboard press equipped with the condenser and
combustion unit described by the commenter cannot comply using the PBCO.
In the proposed PCWP rule, we intentionally omitted absorbers
(e.g., wet scrubbers) from the list of potential control devices
because these technologies generally are not reliable for reducing HAP
emissions. These wet systems may achieve short-term reductions in THC
or gaseous HAP emissions; however, the HAP and THC control efficiency
data, which range from slightly positive to negative values, indicate
that the ability of these wet systems to absorb water-soluble compounds
(such as formaldehyde) diminishes as the recirculating scrubbing liquid
becomes saturated with these compounds. We wished to limit the examples
included in the definition of control device to those devices for which
we have data to demonstrate that they are effective in reducing HAP
emissions from PCWP facilities. However, we note that the definition
includes the phrase ``but not limited to'' and does not exclude other
types of controls. We are aware that new technologies (some of which
may be adsorption-based or absorption-based) may be developed that
effectively reduce HAP emissions from PCWP sources. The definition of
control device does not prevent their development or use.
Facilities using wet scrubbers or WESP to meet the add-on APCD or
emissions averaging compliance options can petition the Administrator
for approval of site-specific operating requirements to be used in
demonstrating continuous compliance. Alternatively, facilities using a
wet scrubber or WESP may use a THC CEMS to show that the THC
concentration in the APCD exhaust remains below the minimum
concentration established during the performance test. In addition,
facilities using wet control devices (e.g., wet scrubber or WESP) as
the sole means of reducing HAP emissions must submit with their
Notification of Compliance Status a plan for review and approval to
address how organic HAP captured in the wastewater from the wet control
device are contained or destroyed to minimize re-release to the
atmosphere such that the desired emission reduction is obtained.
Because wet scrubbers or WESP are add-on
[[Page 45970]]
APCD and have variable effects on HAP emissions, today's final rule
specifies that sources cannot use add-on control systems or wet control
devices to meet PBCO. As part of this change, we added a definition of
``wet control device'' to today's final rule. We note that PCWP
facilities demonstrating compliance with the PBCO for process units
equipped with any wet control device that effects HAP emissions must
test prior to the wet control device.
G. Compliance Options
1. Add-On Control System Compliance Options
Comment: We received a number of comments related to the six add-on
control systems compliance options and how these options might be
implemented at an actual PCWP facility. One commenter argued that the
use of multiple compliance options for add-on control systems will make
it difficult for State agencies to determine if a facility is actually
in compliance. The commenter pointed out that, if a facility tested for
two options but passed only one, it would still be in compliance.
However, the commenter stated that the rule as proposed was unclear
whether a facility would be in violation if the facility chose to test
for one option, failed that test, and then conducted another test to
determine compliance with a different option. The commenter contended
that this would constitute a violation of the standard, and any
retesting to determine compliance with a different option would not
reverse the initial violation. Therefore, the commenter requested that
we clarify that the option to use the most beneficial results of two or
more test methods applies only when these tests are conducted during a
single performance test. According to the commenter, any facility that
chose to use only one test method during the compliance test would have
to accept the results of that test.
Other commenters argued that a facility should be able to switch
among the six add-on control options as needed to maintain compliance.
To illustrate the necessity of the ability to switch from one add-on
control option to another, the commenters provided an example whereby
the operator of a veneer dryer might want to demonstrate compliance
with the 90 percent THC reduction option (option 1 in Table 1B to the
final rule) under certain operating conditions and with the 20 parts
per million by volume (ppmv) THC option (option 2 in Table 1B to the
final rule) under other operating conditions. One of the commenters
also noted that production starts and stops and minor malfunctions are
common at PCWP facilities, and most of them do not affect the
performance of the air pollution control device. However, frequent SSM
events resulting in a low concentration to the inlet of the control
device could affect a facility's ability to comply with the percent
reduction option. In this case, the commenter stated that the freedom
to switch compliance options would be valuable. For these reasons, the
commenters requested that we explicitly state in the final PCWP rule
that ``a facility only need comply with any one of the six options at
any one time, and that it can change between them as needed to fit
process operating conditions.''
Response: We understand the commenters' concerns on this issue and
have written the final rule to clarify our intentions regarding how the
add-on control system compliance options should be implemented at PCWP
facilities. The proposed rule states at 40 CFR 63.2240 that ``You
cannot use multiple compliance options for a single process unit.'' We
included this provision to prevent PCWP sources from partitioning
emissions from a single process unit and then applying different
control options to each portion of the emissions stream. The MACT floor
determinations and compliance options were all based on the full flow
of emissions from process units, and therefore, compliance options
should be applied to the same mass of emissions to ensure that the
required MACT floor emissions reductions are achieved. When including
this restriction, we did not intend necessarily to limit PCWP
facilities to only one of the six options for add-on control systems.
We did assume that each source would likely select only one option, and
that at any point in time for purposes of assessing compliance, the
given compliance option would have been pre-selected and reflected as
applicable in the source's permit. In fact, in discussions with
industry representatives prior to proposal, they expressed concern that
the final rule be written to make it clear that a source would only
have to comply with one option and not all six.
Based on available data, we expect that most facilities will be
able to demonstrate compliance with more than one of the compliance
options for add-on control systems. When developing the six compliance
options for add-on control systems, we felt that PCWP facilities would
conduct emissions testing (e.g., inlet and outlet testing for THC,
methanol, and formaldehyde over a range of APCD operating temperatures)
and then, based on the results of testing, select the option that
provides them with the most operating flexibility as well as an
acceptable compliance margin (i.e., select the option that they feel
will be easiest for them to meet on a continuous basis under varying
conditions). The operating parameter limit to be reflected in the
source's permit (e.g., minimum temperature) would be based on the
measurements made during the compliant test runs. For example, if test
results show that a facility can achieve 90 percent reduction for
formaldehyde, 92 percent reduction for methanol, and 94 percent
reduction for THC, then the facility may decide to reduce THC emissions
by 90 percent, since this option appears to provide the greatest
compliance margin. The corresponding operating parameter level measured
during the testing (e.g., minimum 15-minute RTO temperature during a
three-run test) would then be set as the operating limit in the permit
for that source. In this example, if the RTO operating temperature
drops below the operating limit, that would be a deviation, and any
subsequent retesting done by the facility would presumably be done
based on the chosen compliance option (e.g., reduce THC emissions by 90
percent). Determining compliance in this case is relatively
straightforward. However, we are aware that State agencies may simply
refer to a NESHAP as part of a permit and not stipulate which
compliance option the facility must meet. In these cases, we agree with
the commenter who was concerned that compliance can be complicated when
the referenced NESHAP contains multiple options, and that such a broad
reference would not be adequate to identify the particular option (and
parameter operating limits) applicable to the source. We also agree
that, if a facility selects multiple options under the compliance
options for add-on control systems, it should be required to conduct
all necessary testing associated with compliance with the selected
options concurrently. In addition the facility should obtain permit
terms reflecting these options as alternate operating scenarios that
clearly identify at what points and under what conditions the different
options apply, such that compliance can be determined during a single
time frame. For example, if the source wishes to include options 1, 3,
and 5 in their permit, then it must perform inlet and outlet testing
for THC, methanol, and formaldehyde any time the State agency has
reason to require a repeat performance test (if all three options are
simultaneously applicable) or test for the single applicable option
[[Page 45971]]
that corresponds to the given time and condition (if the options apply
as alternate operating scenarios under different conditions). With this
approach, we would avoid situations where a facility retests to
determine compliance with a compliance option, fails to demonstrate
compliance with that option, and then conducts additional testing to
determine compliance with other options that are not pre-established as
applicable at a later date.
The final rule clarifies our intentions regarding the use of
multiple control options with respect to add-on control systems versus
the combining of control options for a single process unit. The
language in 40 CFR 63.2240 of the final rule has been modified to
remove the proposed text stating that a source ``cannot use multiple
compliance options for a single process unit'' and replace it with a
statement that a source ``cannot combine compliance options in
paragraphs (a) [PBCO], (b) [add-on control systems compliance options]
or (c) [emissions averaging provisions] for a single process unit.'' We
feel that this wording change clarifies our intention to prevent
sources from applying different control options to different portions
of the emissions from a single process unit, while leaving open the
potential for PCWP facilities to be able to include multiple compliance
options for add-on control systems (i.e., one option per defined
operating condition) in a State permit. Although add-on controls are
used in emissions averaging plans to achieve full or partial control of
emissions from a given process unit, the emissions from a single
process unit cannot be parceled such that a portion of the emissions
meets one of the add-on control system compliance options and another
portion is used as part of an EAP. The final rule continues to state
that sources must meet at least one of the six options for add-on
control systems.
2. PBCO Limits
Comment: Several commenters requested that PCWP facilities be
allowed to use add-on control methods to achieve the PBCO limits. The
commenters argued that allowing compliance with the PBCO using APCD is
consistent with other MACT rules and P2 approaches. According to the
commenters, numerous NESHAP allow emissions limits to be reached using
add-on controls, P2 techniques, or a combination of both. The
commenters stated that there was no legal or policy basis for imposing
restrictions on the use of PBCO in the PCWP MACT. The commenters also
stated that using add-on controls to comply with PBCO will benefit
facilities that have process units that emit low levels of HAP.
According to the commenter, some companies have already implemented P2
strategies that have been established as BACT in a prevention of
significant deterioration (PSD) permit. Because these P2 strategies may
fall short of the PBCO, companies implementing these strategies would
be unable to achieve compliance with the proposed rule without
abandoning the P2 strategy and installing full control. The commenters
also stated that incorporating add-on controls in the PBCO would
provide incentives to find low-energy pollution control equipment. The
commenters gave an example whereby part of the emission unit exhaust
could be used as combustion air for an onsite boiler. The commenters
noted that in most cases, the boiler could only handle a portion of the
exhaust from multiple dryer stacks. The commenters stated that by
combining this type of partial control approach with low-temperature
drying, a facility may be able to meet the applicable dryer PBCO limit.
According to the commenters, in this case, allowing for partial control
would exclude the need for RTO technology and would provide a net
benefit to the environment with a reduction of collateral oxidizer
emissions. The commenters gave another example in which a facility with
a conveyor strand dryer could send the exhaust from the first dryer
section to a burner and then send the heat back to the dryer; the
emissions from the remaining dryer sections would be uncontrolled if
the total emissions were below the PBCO limit. In a third example
provided by the commenters, a facility would remove enough HAP to
comply with the PBCO limit using a scrubber, which would require less
energy than incineration.
Response: As in the proposed rule, the final rule does not allow
sources to comply with the PBCO through the use of add-on control
systems. Our intention for including the PBCO was to provide an
alternative to add-on controls (e.g., allow for and encourage the
exploration of P2, which currently has not been demonstrated as
achieved by PCWP sources) and not to create another compliance option
for sources equipped with add-on control systems that could
inadvertently allow add-on control equipped systems to not perform to
expected control efficiencies. Sources equipped with add-on control
systems already have six different compliance options from which to
choose, in addition to the emissions averaging compliance option. We
note that the six options for add-on control systems are based on
emissions reductions achievable with MACT control devices and thus are
a measure of the performance of MACT control devices. This might not be
true if a source combined PBCO and add-on controls, as explained below.
At proposal, we established PBCO limits for 10 process unit groups.
Initially, we felt that we needed total HAP data for at least one
process unit in each process unit group that was equipped with a
control system in order to establish the PBCO limits. However, we had
to discard this approach because controlled total HAP data are not
available for half (5 of 10) of the process unit groups. We developed a
number of other approaches to establishing PBCO, and then compared the
results of these approaches, where possible, with actual emissions in
the outlet of MACT control devices. The approach that yielded results
closest to actual emissions in the control device outlets was an
approach based on a 90 percent reduction from the average emissions
each process unit group. Thus, this approach was the one that resulted
in limits that would most closely represent an alternative to the six
compliance options for add-on control systems. However, our intention
was not to develop an alternative limit to the six limits already
established for add-on control devices. Our intention was to develop an
alternative for P2 techniques. We decided to select an approach that
allows sources that develop P2 techniques (or are otherwise inherently
low-emitting sources) to comply and that reduces HAP emissions without
generating the NOX emissions associated with incineration-
based controls. As a result, we selected a 90 percent reduction from
the highest data point within each process unit group, because the
results appeared to be at levels that would not preclude the
development of environmentally beneficial P2 options as MACT.
If PBCO were allowed as another option for measuring the
performance of add-on control devices, operators could run the APCD so
that the APCD would not achieve MACT level emissions reductions, but
would meet the PBCO. We note that we did not develop the methanol and
formaldehyde add-on control options (options 4 and 6 in Table 1B to the
final rule) based on typical or maximum levels of methanol and
formaldehyde found in the outlet of the control devices, but instead
looked at the performance of the MACT control devices in reducing these
HAP, set the levels based on the method detection limits for these
compounds, and
[[Page 45972]]
included a minimum inlet concentration requirement for the use of the
outlet concentration options to ensure that HAP emissions reductions
are achieved. Allowing the use of APCD to comply with PBCO could allow
circumvention of such optimization, which could render the MACT control
itself to be less effective than MACT.
Regarding the other MACT standards referenced by the commenters, we
agree that these other rules may allow facilities more flexibility in
meeting a production-based option (e.g., ``lb/ton'' emission limit);
however, we cannot allow add-on controls to be used to meet the PBCO in
the final PCWP rule because doing so would render these limits not
equivalent to the other compliance options. For example, consider a
typical wood products press with an annual production rate of 100
million square feet of board per year and a total HAP emission rate of
1.0 pound per thousand square feet of board on a \3/4\-inch basis (lb/
MSF \3/4\''). On an annual basis, the example press emits 50 tons of
HAP per year. If the example press complies with the 90 percent HAP
reduction requirement, then the HAP emissions reductions achieved will
be at least 45 tons/yr. However, if this same press were allowed to
comply with the applicable PBCO limit (0.30 lb/MSF \3/4\'') using an
APCD (e.g., RTO), then the emissions reductions achieved could be as
little as 35 tons/yr if the APCD is only applied to a portion of the
press' emissions or if the APCD is not operated at MACT-level
efficiency. Not only would a significantly lower HAP emission reduction
be achieved in this situation, but there also would not be any net
benefit to the environment to justify the lower HAP reduction (i.e.,
NOX emissions would still be created). Therefore, we feel it
is appropriate and in keeping with the MACT floor to require PCWP
process units with uncontrolled HAP emissions above the PBCO thresholds
to achieve the full 90 percent reduction in emissions. We also wish to
clarify that a PCWP facility may use any number of compliance options,
as long as these options are not combined for an individual process
unit. For example, a facility may choose to meet the applicable PBCO
limit for one dryer, control emissions from a blender to avoid
controlling emissions on the remaining two dryers as part of an
emissions average, and comply with one of the add-on control systems
compliance options for the press.
Regarding the examples cited by the commenter as candidates for a
PBCO if add-on controls were allowed, we note that the final rule
includes a revised MACT floor for existing conveyor strand dryers, such
that existing conveyor strand dryers that send the emissions from the
first dryer section back to the combustion unit that heats the dryer
should be able to meet the rule requirements without additional
controls. In addition, partial control (e.g., routing part of the
emission stream from a process unit to an onsite combustion unit for
incineration) is allowed as part of an EAP as long as the actual
emissions reductions achieved are greater than or equal to the required
emissions reductions. When partial control is used as part of an EAP,
the overall reductions are equivalent to what would be achieved if a
source elected to comply using the add-on control system compliance
options; however, the same would not be true if partial control were
used to comply with a PBCO limit. Therefore partial incineration
control is not allowed in the PBCO.
Regarding the use of scrubbers to comply with a PBCO, as stated
earlier in this preamble, the PCWP industry's own data do not support
wet scrubbers as a reliable control technology for HAP, and sources
equipped with wet control devices will be required to test prior to the
wet control device if they elect to comply with a PBCO.
Comment: Several commenters stated that PCWP facilities should be
allowed to neglect nondetect HAP measurements for PBCO calculations.
The commenters argued that if a facility is forced to use values of
one-half the detection limit for nondetect HAP, that facility may be
unable to use PBCO because the mass of emissions attributed to
undetected compounds may consume 50 percent or more of the PBCO limit.
The commenters also noted that the detection levels measured in the
field by the NCASI test method, NCASI IM/CAN/WP-99.01, generally range
between 0.35 and 1 ppm, and the detection levels of the FTIR method
averages about 1 ppm. According to the commenters, even at these low
concentrations, using one-half the detection limit for nondetect
compounds can put the PBCO out of reach for a high-flow-rate PCWP
stream. The commenters also provided a sample calculation to
demonstrate the effect that the detection level has on the compliance
calculation.
Response: In responding to this request, we reviewed the
information supplied by the commenters and analyzed the potential
effects of making the requested change using available emissions data.
After reviewing the total HAP data used to establish the PBCO limits,
we decided that sources should be able to treat nondetect measurements
for an individual HAP as zero for the sole purpose of determining
compliance with the PBCO, if, and only if, the following two conditions
are met: (1) The detection limit for that pollutant is set at a value
that is less than or equal to 1 ppmvd, and (2) emissions of that
pollutant are nondetect for all three test runs. We included the first
condition to prevent test contractors from setting the detection limits
too high, and thus generating false zeroes. We selected 1 ppmvd as the
maximum detection limit value because it matches the detection limits
achievable with the test methods included in the final PCWP rule. We
included the second condition to ensure that the source is truly low-
emitting, as evidenced by three nondetect test runs. If emissions of
the HAP are detected during any one test run, then any nondetect runs
must be treated as being equal to one-half the detection limit. The
option to treat nondetect measurements as zero does not apply to the
compliance options for add-on control systems because treating the
outlet emissions from a control device as zero would artificially
increase the calculated control efficiency for that pollutant to 100
percent.
To ensure that the PBCO limits were developed in a manner
consistent with how they would be applied, the PBCO limits were
recalculated using zero for nondetect measurements when all test runs
were nondetect. As a result, the PBCO limit for reconstituted wood
product board coolers changed from 0.015 to 0.014 lb/MSF \3/4\''. No
other PBCO limits changed as a result of using zero for nondetects when
calculating the PBCO limits.
We added a new PBCO limit to the final rule for secondary tube
dryers. This new limit corresponds to our decision to treat primary and
secondary tube dryers as separate process units, as discussed
previously in this preamble. The final rule also differentiates between
rotary strand dryers and conveyor strand dryers, as discussed
previously in this preamble; however, no new PBCO limits have been
added for these two process units groups. The final PBCO limit for
rotary strand dryers is the same as the proposed limit for strand
dryers because the data used to establish the proposed PBCO limit was
based on data from rotary strand dryers exclusively. We do not have the
necessary data to establish a PBCO for conveyor strand dryers, and thus
the final rule does not include a PBCO limit for that process unit group.
3. Emissions Averaging Provisions
Comment: Industry commenters generally expressed support for the
[[Page 45973]]
inclusion of an emissions averaging program in the PCWP rule as
proposed, but requested that the proposed provisions be modified to
allow for broader use of emissions averaging at PCWP facilities.
Requested modifications include allowing sources to receive credit for
achieving emissions reductions greater than 90 percent; basing
compliance on a single pollutant; allowing sources to combine emissions
averaging with PBCO; and allowing sources to receive credit for P2
alternatives as part of an EAP.
Response: We included an emission averaging compliance option in
the proposed rule as an equivalent, more flexible, and less costly
alternative to the compliance options for add-on control systems.
Unlike previous MACT standards with emissions averaging, the proposed
(and final) emissions averaging provisions in the PCWP rule do not
include (1) limits on the number of sources that can be included in an
emissions average, (2) requirements for a hazard or risk analysis, or
(3) application of a 10 percent discount factor to emissions credit
calculations. In addition, the emissions averaging provisions in the
final PCWP rule require that credits for emissions reductions be
achieved using APCD, and that the EAP be based on emissions of the six
predominant HAP emitted from PCWP process units, referred to as total
HAP. Also, the emissions averaging provisions do not allow credit for
reductions beyond 90 percent.
We disagree with the commenters' request to allow credit for
achieving greater than 90 percent control of HAP as part of an EAP. We
note that the 90 percent MACT floor level (upon which the emissions
averaging provisions are based) reflects the inherent variability in
uncontrolled emissions from PCWP process units and the decline in
performance of control devices applied to these process units. The data
set used to establish the MACT floor is composed of point-in-time test
reports, some of which show a greater than 90 percent control
efficiency; however, we selected 90 percent as the MACT floor level of
control to reflect inherent performance variability. Therefore, it
would be inappropriate to allow PCWP facilities to receive credit for
similar point-in-time performance tests showing greater than 90 percent
control, considering that the same types of control technologies would
be used.
Regarding the commenters' request to allow credit for greater than
90 percent control for those sources with no MACT control requirements,
we maintain that this would be inappropriate because the same issues of
emissions variability and control device performance apply to those
emission sources, and they likely would share control devices with PCWP
process units that do have MACT control requirements.
We have rejected the commenters' suggestion to base the emissions
averaging provisions on a single pollutant (e.g., THC, methanol or
formaldehyde), and retained the requirement in the final rule that the
EAP must be based on total HAP. The predominant HAP emitted from a
given process unit varies, with some process units emitting methanol as
the predominant HAP and others emitting formaldehyde or acetaldehyde as
the predominant HAP. However, the predominant HAP will always be one of
the six we have identified in the definition of total HAP in the final
PCWP rule. If we based the EAP on only one pollutant, process units
that emit the target HAP in small quantities will not be correctly
accounted for in the EAP, resulting in potentially less stringent
control and greater potential risk than would result with other control
options. As noted above, we did not include a hazard/risk study as part
of the proposed EAP because we were requiring that the emissions
reductions be based on total HAP, and PCWP process units generally emit
the same six primary HAP, although in different quantities and ratios.
Basing the EAP on a single pollutant would eliminate our rationale for
not requiring a risk analysis. We also note that, while THC emissions
are an acceptable surrogate for monitoring the performance of an add-on
control device (same control device mechanisms that reduce THC
emissions reduce HAP emissions), THC emissions are not an accurate
surrogate for establishing baseline HAP emissions for uncontrolled
process units, and thus the EAP should not be based solely on THC
emissions. Although all PCWP process units emit THC, uncontrolled THC
emissions from softwoods are substantially higher than from hardwoods
due to non-HAP compounds (e.g., pinenes) present in softwoods.
Therefore, allowing sources without add-on controls to focus on THC
reductions achieved by increasing hardwood usage might reduce THC
emissions but would have a minimal impact on HAP emissions. For these
reasons, we feel that, for the purpose of the final rulemaking, THC
should only be used as a surrogate for HAP when assessing the
performance of an add-on control device, and should not be used as a
surrogate for establishing the required and actual mass removal of HAP
as part of an EAP.
We disagree with the commenters that combining the emissions
averaging option and PBCO will result in equivalent emissions
reductions. As we stated in our response to previous comments in this
section regarding PBCO, we developed the PBCO limits to provide an
option for sources that develop P2 techniques. The PBCO limits
represent applicability cutoffs such that sources with emissions below
the applicable PBCO thresholds are not required to further reduce those
emissions below MACT levels. By combining PBCO limits with the EAP, as
proposed by the commenter, we would be allowing higher-emitting sources
(i.e., those that cannot meet a PBCO and which should be controlled) to
escape controls by artificially lowering their emissions (using the
credits from the EAP) to levels that would qualify as low-emitting
(below PBCO limits). This is counter to the intent of the PBCO and
would result in lower emissions reductions than would be achieved
without combining these two compliance options; therefore, this does
not represent an option that is equivalent to the MACT floor and is not
allowed in the final rule.
We also disagree with the commenters' suggestion to modify the
emissions averaging provisions to allow sources to receive credit for
P2 projects because: (1) Compliance options (i.e., PBCO) already exist
for any P2 projects that prove feasible, and (2) inclusion of currently
undemonstrated P2 projects within EAP would unnecessarily complicate
these plans and hamper enforcement. As we noted previously in this
preamble, the final rule allows PCWP facilities to use both P2 (i.e.,
the PBCO) and emissions averaging at the same facility; sources are
only limited in that they cannot apply both options to the same process
unit. We also disagree with the commenters' assertion that quantifying
the emissions reductions from P2 projects would not be difficult.
Quantifying the emissions reductions associated with P2 projects has
historically been a contentious issue, especially when a baseline
emission level must be established from which to calculate the
emissions reduction. We feel that the same issues apply for PCWP
facilities, especially given the fact that P2 techniques have not been
widely used or documented in the PCWP industry. In contrast, emissions
reductions achieved through the use of add-on control systems are
easily documented. The PBCO were established to address the future
development and implementation of P2 techniques; however, the resultant
[[Page 45974]]
PBCO limits do not require that emissions reductions be determined.
Instead, sources simply demonstrate that they are below the PBCO limit
and will continue to operate in a manner that ensures they will remain
below the PBCO limit.
Regarding the suggested P2 option of increasing a facility's use of
hardwood species, in addressing other issues, commenters stressed the
difficulties associated with maintaining a consistent wood material
flow in terms of species, moisture content, etc., which would suggest
that an operating condition based on maintaining a set level of wood
species would be unworkable. Furthermore, for veneer dryers, where
species identification (hardwood vs. softwood), and thus enforcement,
is fairly straightforward from the standpoint of both visual inspection
and end-product, we have already established separate MACT floors for
softwood and hardwood veneer dryers (and require no further emissions
reductions from hardwood veneer dryers). When the end product is
particleboard or MDF, and the raw material is in the form of wood
chips, planer shavings, or sawdust, determining how much of that
material is softwood versus hardwood would be very difficult, and
likely unenforceable. Because of commenters' concerns that an operating
condition based on wood species is technically unworkable and the
associated enforcement issues, we feel this option is not viable.
Regarding process changes such as reformulation, lowering dryer
temperature, and routing process unit exhaust to existing combustion
devices, the final rule already includes compliance options that would
accommodate all of these strategies. For example, product reformulation
and lowering dryer temperature are potential P2 options, and the PBCO
limits would apply if the P2 efforts sufficiently lower emissions. The
final PCWP rule distinguishes between green (high temperature, high
moisture) rotary dryers and dry (low temperature, low moisture) rotary
dryers and requires no further emissions reductions from dry rotary
dryers. Regarding the use of existing combustion units as control
devices, the final rule allows sources to route emissions to onsite
combustion units for incineration. The final rule also allows sources
to control a portion of a process unit's emission stream as part of an
emissions average. However, we disagree that incineration of emissions
in onsite process units is a P2 measure. Therefore, compliance with the
PBCO using process incineration is not allowed in the final rule. The
add-on control system and emissions averaging compliance options are
available for process units controlled by routing exhaust to an onsite
combustion unit.
The final PCWP rule does not allow production curtailment to be
counted as part of an EAP. As stated in the preamble to the proposed
rule (68 FR 1276, January 9, 2003), we do not have facility-wide
uncontrolled emissions data and facility-wide controlled emissions data
for each PCWP facility to determine the baseline emissions and percent
reduction in HAP achieved by each facility. Therefore, the MACT floor
is not based on facility-wide emissions and emissions reductions
achieved during year ``x.'' Instead, the MACT floor is based on (1) the
presence or absence of certain MACT controls (in place as of April
2000) on certain types of process units and (2) test data showing that
these controls reduce emissions by greater than or equal to 90 percent.
We applied the MACT floor methodology at the process unit level because
we had the most accurate data at the process-unit level, making this
approach the most technically and legally sound. The PCWP industry is
very dynamic, with frequent shutdowns of equipment for maintenance, and
occasionally longer shutdowns (e.g., month-long), if demand drops. The
final PCWP rule requires emissions from specified process units at
impacted PCWP facilities to be reduced by 90 percent, regardless of
what the levels of emissions are for those facilities in a particular
year. Therefore, implementation of the final PCWP rule at individual
PCWP facilities will result in greater emissions reductions in years of
greater production and lesser emissions reductions during years of
lower production. As mentioned in the response to the previous comment,
the emissions averaging provisions must achieve emissions reductions
that are greater than or equal to those that would be achieved using
the add-on control system compliance options, which specify which
process units must be controlled. If we allowed credit for production
curtailments, the overall emissions reductions achieved through the
emissions averaging provisions would not be equivalent to what would be
achieved through the use of the add-on control system compliance
options, and therefore, the EAP would not be a MACT-equivalent
alternative. For example, if we allowed production curtailments to
count toward an emissions average, then a facility that shuts down one
of two parallel production lines (each of which includes dryers and a
press, plus HAP-emitting equipment that does not have associated
control requirements) may not be required to control the emissions from
any of the dryers or press on the remaining production line. However,
if the same facility opted to comply with the add-on control system
compliance options, then it would be required to control the press and
dryer emissions from the remaining production line by 90 percent
regardless of whether or not the other production line was shut down.
In order to maintain equivalency between the emissions averaging
provisions and the add-on control system compliance options and to
preserve the required HAP emissions reductions, the final PCWP rule
does not allow production curtailment to be counted as part of an EAP.
Comment: One commenter objected to the inclusion of the emissions
averaging option in the rule primarily because of the lack of a
requirement to conduct a hazard or risk study. This commenter asserted
that removing a certain mass of HAP regardless of identity is not
equivalent to the other compliance options, and when the dose-response
and exposure data are examined, it should be obvious that trading one
HAP for another to meet a RMR is not an acceptable option. The
commenter noted that there are currently no methods for weighting the
toxicity of HAP and that the effects of simultaneous exposure to
several HAP also are unknown.
Response: We disagree with commenter's assertion that inclusion of
the emissions averaging provisions will potentially increase toxic
emissions at certain PCWP process units. As stated in the preamble to
the proposed rule (68 FR 1289, January 9, 2003), PCWP facilities have
fewer pollutants of concern (as compared to HON facilities) and are
likely to have similar HAP emissions from the emission points (process
units) that would be used to generate debits and credits. The PCWP
facilities emit six primary HAP, whereas HON facilities may emit over
140 different HAP. The PCWP facilities choosing to comply through
emission averaging must account for the emissions of the six primary
HAP (total HAP), which represent greater than 96 percent of the mass of
HAP emitted from PCWP process units. Because the MACT control
technologies are effective in reducing the emissions of all six of
these HAP, and the emissions averaging provisions require the use of
add-on control technologies for credit-generating sources in an EAP, we
feel that the emissions averaging provisions will achieve a hazard/risk
benefit
[[Page 45975]]
comparable to what would be achieved through point-by-point compliance.
Although the final rule does not require a hazard/risk study, States
will still have the discretion to require a PCWP facility that
requested approval of an EAP to conduct a hazard/risk study (or could
preclude the facility from using emissions averaging altogether).
Comment: Several commenters requested that we write the definitions
of some of the variables used in the emissions averaging equations in
the final rule to clarify that sources can take credit for emission
reductions achieved through partial control of debit-generating process
units.
Response: We agree with the commenters' request and have written
the definitions of some of the variables used in the emissions
averaging equations in today's final rule to clarify that partial
credits generated from debit-generating process units that are
undercontrolled can be included in the calculation of the AMR. For
example, a PCWP facility may decide to control 30 percent of the
emissions from a green rotary dryer and 80 percent of the emissions
from a blender as part of an EAP in order to achieve a HAP reduction
that is the same as or greater than what the facility would have
achieved by controlling the green dryer emissions alone by 90 percent.
In this example, the green rotary dryer is a debit-generating unit
because it has MACT control requirements; however, the green dryer can
receive credit in the AMR calculation for any partial emissions
reductions that are achieved.
H. Testing and Monitoring Requirements
1. Test Methods
Comment: Several commenters noted that one of the NCASI test
methods, NCASI IM/CAN/WP-99.01, has been updated, and requested that
the final rule refer to the revised version. One of the commenters
provided a revised version of the method, identified as NCASI IM/CAN/
WP-99.02. This commenter noted that the trained NCASI sampling team was
able to get good consistent results with the original version of the
method both in the laboratory and in the field, but that sampling
contractors had difficulty obtaining valid results. The commenter
maintained that the revised version is easier to understand, includes
more details, and reflects the comments of the contractors that have
experience with the original method. The commenter also stated that the
quality assurance requirements were strengthened in the revised version
to ensure good results. Several commenters also noted that NCASI is
currently developing a new method for measuring the six HAP (total HAP)
listed in the PCWP rule as proposed. Therefore, the commenters
requested that we include language in the final rule that would allow
PCWP facilities to use future methods once they have been reviewed by
EPA and have passed Method 301 validation at a PCWP plant.
Response: We reviewed the revised NCASI method IM/CAN/WP-99.02
supplied by the commenter and agree that the revised method is
appropriate for measurement of the six HAP that comprise ``total HAP;''
therefore, we have included NCASI IM/CAN/WP-99.02 in the today's final
rule. Regarding the development of future test methods, if and when a
new method for measuring HAP from PCWP sources is developed and
validated via EPA Method 301, we will issue an amendment to the final
rule to include the use of that method as an alternative to the methods
included in the final rule for measuring total HAP (i.e., NCASI Method
IM/CAN/WP/99.02 and EPA Method 320--Measurement of Vapor Phase Organic
and Inorganic Emission by Extractive FTIR). In the meantime, if the new
method is validated using Method 301, then the Method 301 results can
be used to request approval to use the new method on a site-specific basis.
Comment: Several commenters noted that the tracer gas method for
determining capture efficiency, developed by a PCWP company and
included in the proposed rule (68 FR 1276, appendix A to 40 CFR part
63), is a work in progress. These commenters included with their
comments a copy of field validation tests conducted at a PCWP facility.
The commenters noted that future tests are planned using the tracer gas
method and that the results of these tests should help EPA improve the
use and application of the proposed tracer gas test.
Response: We have reviewed the results of the first field
validation test of the tracer gas method and note that the commenters
did not provide any specific recommendations for modifying the tracer
gas method as it was proposed. Therefore, other than a few minor
wording changes, we did not make any substantive changes to the tracer
gas method in the final rule. If the results of subsequent field tests
demonstrate a need to (further) modify the tracer gas method, we will
issue an amendment to the final rule to incorporate the necessary changes.
2. Sampling Locations
Comment: Several commenters recommended that the final rule be
reworded to clearly state that inlet sampling should take place at the
functional inlet of a control device sequence or at the primary HAP
control device inlet. For example, the commenters noted that the final
rule needs to clarify that sampling should take place at the inlet of a
WESP that precedes an RTO instead of between the two devices. The
commenters noted that many WESP-RTO control systems are too closely
coupled to allow for a sampling location in between that meets the
requirements of Method 1 or 1A, 40 CFR 60, appendix A.
Response: We agree with the commenters and have written the final
PCWP rule to indicate that, for HAP-altering controls in sequence, such
as a wet control device followed by a thermal oxidizer, sampling sites
must be located at the functional inlet of the control sequence (e.g.,
prior to the wet control device) and at the outlet of the control
sequence (e.g., thermal oxidizer outlet) and prior to any releases to
the atmosphere. In addition, as discussed previously in this preamble,
the final rule also clarifies that facilities demonstrating compliance
with a PBCO limit for a process unit equipped with a wet control device
must locate the sampling site prior to the wet control device.
3. Testing Under Representative Operating Conditions
Comment: Several commenters objected to the proposed requirement to
test process units under representative operating conditions. The
commenters argued that, because the initial compliance tests determine
the outer limits of compliance, those tests should be conducted at the
boundaries of expected performance for the process and control units.
These commenters noted that testing at representative conditions would
not accurately simulate true operating conditions, and thus, the
operating parameter limits would be too narrow. Therefore, the
commenters contended that the final rule should specify that initial
compliance tests should be conducted at the extremes of the expected
operating range for the parameter and control device function. In
addition, one of the commenters noted that the testing provisions
should also address potential conflicts with traditional State
requirements to test at maximum or design conditions.
Response: The proposed rule defined representative operating
conditions as
[[Page 45976]]
those conditions under which ``the process unit will typically be
operating in the future, including use of a representative range of
materials[* * *] and representative temperature ranges.'' We disagree
that the proposed requirement to test under representative operating
conditions will conflict with State requirements and result in
operating parameter limits/ranges that are too narrow. We wish to
clarify that the definition of representative operating conditions
refers to the full range of conditions at which the process unit will
be operating in the future. We expect that facilities will test under a
variety of conditions, including upper and/or lower bounds, to better
define the minimum or maximum operating parameter limit or broaden
their operating limit ranges (where applicable). For example, if a
facility generally operates a process unit (equipped with an RTO) under
conditions that require the RTO to be operated at a minimum temperature
of 1450[deg]F to ensure compliance with the standards, but at other
times operates that process unit under conditions such that the minimum
RTO operating temperature must be 1525[deg]F to ensure compliance, then
the facility has two options. One option is for the facility to
incorporate both of these operating conditions into their permit such
that they are subject to two different operating parameter limits
(minimum temperatures), one for each (defined) operating condition. As
an alternative, the facility could decide to comply with the parameter
limit associated with the worst-case operating conditions (most
challenging conditions for the RTO), which in this example would
correspond to maintaining a minimum RTO operating temperature of
1525[deg]F, and thus, they could demonstrate continuous compliance
regardless of the operating condition as long as they maintained the
RTO temperature at or above 1525[deg]F. We have revised the monitoring
requirements for process units without control devices to allow these
sources to establish a range of compliant parameter values. In
addition, those PCWP facilities operating biofilters must maintain
their biofilter bed temperature within the range established during the
initial performance test and, if available, previous performance tests.
If the final PCWP rule required testing at maximum operating
conditions, there would be no way for facilities to identify their
operating parameter ranges. For these reasons, we maintain that the
requirement to test at representative operating conditions is
appropriate for the PCWP rule.
4. Process Incineration Monitoring Requirements
Comment: Several commenters expressed approval for the proposed
exemption from testing and monitoring requirements for those process
units with emissions introduced into the flame zone of an onsite
combustion unit with a capacity greater than or equal to 44 megawatts
(MW) (150 million Btu/hr). In addition, several of these commenters
requested that we expand upon this exemption in the final rule. First,
the commenters requested that we extend the exemption to include
situations where the process unit exhaust is introduced into the
combustion unit with the combustion air. The commenters noted that we
had included such exemptions in the HON (40 CFR part 63, subpart G) and
in the Pulp and Paper Cluster Rule (40 CFR part 63, subpart S) in
recognition of the fact that boilers greater than 44 MW typically had
greater than \3/4\-second residence time, ran hotter than 1,500[deg]F,
and usually had destruction efficiencies greater than 98 percent (see
65 FR 3909, January 25, 2000, and 65 FR 80762, December 22, 2000, at
Sec. 63.443(d)(4)(ii)). The commenters stated that the design and
construction of PCWP boilers follow the same principles that would
allow for these operating conditions. Second, the commenters requested
that we also exempt smaller combustion units (less than 44 MW, or 150
million Btu/hr) from the testing and monitoring requirements if the
process unit exhaust is introduced into the flame zone of the
combustion unit. The commenters noted that most of the combustion units
associated at PCWP facilities are smaller units and that testing of
these units can be complicated by their configuration and integration
with other process units.
Response: After reviewing available information on process
incineration at PCWP facilities, we decided to include smaller
combustion units in the exemption from testing and monitoring
requirements if the process exhaust enters into the flame zone. As part
of this change, we have included definitions of ``flame zone'' and
``combustion unit'' in the final rule. However, we decided not to
include an exemption for PCWP combustion units that introduce the
process exhaust with the combustion air. As noted by the commenters,
the HON and the final pulp and paper MACT I rule exempt from testing
and monitoring requirements combustion devices with heat input capacity
greater than or equal to 44 MW. The HON also exempts from testing and
monitoring combustion devices with capacity less than 44 MW if the
exhaust gas to be controlled enters with the primary fuel. If the
exhaust gas to be controlled does not enter with the primary fuel, then
testing and continuous monitoring of firebox temperature is required by
the HON. Similarly, the final pulp and paper MACT I rule exempts from
testing and monitoring requirements combustion devices (including
recovery furnaces, lime kilns, boilers, or process heaters) with
capacity less than 44 MW if the exhaust stream to be controlled enters
into the flame zone or with the primary fuel. Similar to the HON and
pulp and paper MACT I rules, the final PCWP rule extends the exemption
from testing and monitoring requirements to combustion units with heat
input capacity less than 44 MW, provided that the exhaust gas to be
treated enters into the combustion unit flame zone. If the exhaust gas
enters into the combustion unit flame zone, the required 90 percent
control efficiency may be assumed. If the exhaust gas does not enter
into the flame zone, then the testing and monitoring requirements for
thermal oxidizers will apply.
As noted by the commenter, the HON and the final pulp and paper
MACT I rule exempted boilers (and recovery furnaces at pulp and paper
mills) with heat input capacity greater than 44 MW from testing and
monitoring requirements because performance data showed that these
large boilers achieve at least 98 percent combustion of HAP when the
emission streams are introduced with the primary fuel, into the flame
zone, or with the combustion air. Lime kilns at pulp and paper mills
were excluded from this provision because we did not have any data to
show that lime kilns can achieve the required destruction efficiency
when the HAP emission stream is introduced with the combustion air.
Therefore, lime kilns at pulp and paper mills that accept HAP emission
streams must introduce the stream into the flame zone or with the
primary fuel. We do not have the data to show that the design and
construction of large (greater than 44 MW) combustion units at PCWP
plants would be similar to boilers found at pulp and paper mills.
Furthermore, combustion units at PCWP plants with heat input capacity
of greater than 44 MW are less prevalent than smaller (i.e., less than
44 MW) PCWP combustion units, and many of these smaller combustion
units are not boilers. As stated above, the final rule exempts these
smaller combustion units from the testing and monitoring requirements
[[Page 45977]]
provided that the HAP emission stream is introduced into the flame
zone. For these reasons, the final PCWP rule does not extend the
exemption from testing and monitoring to those boilers greater than 44
MW that introduce the HAP emission stream with the combustion air.
5. Selection of Operating Parameter Limits for Add-On Control Systems
Comment: Several commenters stated that the inlet static pressure
to a thermal or catalytic oxidizer is not a reliable indicator of the
flow through the oxidizer, the destruction efficiency, or the capture
efficiency. The commenters also noted that the preamble to the PCWP
rule stated that monitoring the static pressure can indicate to the
operator when there is a problem such as plugging. However, the
commenters stated that static pressure is usually the last indicator of
these types of control device problems. As discussed in the
promulgation BID, the commenters agreed that measuring those parameters
helps to assess the overall condition of the oxidizer but provided
reasons why setting limits on these parameters is inappropriate. The
commenters further noted that monitoring the static pressure helps to
control the speed of the fan or the oxidizer dampers so that all the
air flows are balanced. According to the commenters, static pressure is
adjusted to avoid vacuum conditions in the ductwork of multiple-dryer
systems treated by one control device when one dryer is shut down, to
improve emission collection efficiency and prevent fugitive emissions,
and to adjust the pressure drop across a bag filter as it fills with
particulates, among other reasons. However, the commenters stated that,
if operators are required to keep the static pressure within an
operating range, it will limit their ability to maintain capture
efficiency. The commenters expressed similar concerns regarding air
flow rate monitoring and noted that numerous factors affect the air
flow through the control device, including the rate of water removal in
dryers, leakage of tramp air into the process, the number of processes
operating for control units that receive emissions from multiple
production units, and the overall production speed due to process
adjustments. The commenters noted that, in those cases where air flow
to the oxidizer is not constant, monitoring the air flow through the
oxidizer will not be an accurate measure of capture efficiency.
Response: After reviewing the information provided by the
commenters, we agree that, while monitoring the static pressure or air
flow rate helps to assess the overall condition of the oxidizer and
provides an indication that emissions are being captured, setting
operating limits on these parameters is not appropriate for the reasons
given by the commenters. Therefore, today's final rule does not include
the proposed requirement to monitor the static pressure or air flow
rate for thermal and catalytic oxidizers.
Comment: Several commenters requested that we modify the procedures
for determining the minimum operating temperature (operating limit) for
thermal and catalytic oxidizers. The commenters stated that, due to the
normal variation in combustion temperatures, a facility will have to
perform the initial compliance test at lower-than-normal temperature
conditions to ensure that the minimum combustion temperature will be
set at a level that they can continuously meet. The commenters
requested that we allow facilities to operate the thermal oxidizers up
to 50[deg]F lower than the average obtained by the performance test and
allow facilities to operate RCO at a level that is 100[deg]F above the
minimum operating temperature of the catalyst. The commenters also
noted that, when the THC concentration in the inlet is high, the RCO
will not need any additional heat and it can operate at temperatures
higher than the set point. Therefore, if the initial compliance tests
are conducted under these conditions, the operating temperature limit
will be too high for production rates at less than full capacity.
Commenters also stated that, for RCO, the thermocouple should be
placed in a location to measure the temperature of the gas in the
combustion chamber between the catalyst beds instead of in a location
to measure the gas stream before it reaches the catalyst bed. The
commenters noted that, because the gas flow reverses direction in RCO,
the inlet temperature monitor will not consistently measure the gas at
the same point in the process such that sometimes the gas temperature
will be recorded after the catalyst beds instead of before. The
commenters further noted that placement of the monitor inside the
combustion chamber would eliminate the need for multiple monitors and
avoid problems such as overheating and burnout of the catalyst media
caused by the temperature delay between the burner and the RCO inlet.
Response: We disagree with the commenters' request to include a
50[deg]F margin around the minimum operating temperature established
during the thermal oxidizer compliance test. In general, selection of
the representative operating conditions for both the process and the
control device for conducting the performance test is an important, and
sometimes complex, task. We maintain that establishing the add-on
control device operating limit at the level demonstrated during the
performance test is appropriate. We note that the PCWP rule as proposed
allows a facility to select the temperature operating limits based on
site-specific operating conditions, and the facility is able to
consider the need for temperature fluctuations in this selection. The
PCWP rule as proposed requires that the operating limit be based on the
average of the three minimum temperatures measured during a 3-hour
performance test (rather than on the average temperature over the 3-
hour period, for example) to accommodate normal variation during
operation and ensure that the minimum temperature established
represents the lowest of the temperatures measured during the compliant
test. For example, during a 3-hour, three-run performance test, the
operating limit would be determined by averaging together the lowest
15-minute average temperature measured during each of the three runs.
However, continuous compliance with the operating limit is based on a
3-hour block average. For a typical 3-hour set of data, this means that
the 3-hour block average will be higher than the average of the three
lowest 15-minute averages, so the temperature monitoring provisions
already have a built-in compliance margin. In addition, the final rule
allows PCWP facilities to conduct multiple performance tests to set the
minimum operating temperature for RCO and RTO, so PCWP sources would
have the option to conduct their own studies (under a variety of
representative operating conditions) in order to establish the minimum
operating temperature at a level that they could maintain and that
would provide them with an acceptable compliance margin. We feel these
provisions allow sufficient flexibility, and an additional tolerance
for a 50[deg]F temperature variation is not necessary. Therefore, the
final rule does not allow facilities to operate thermal oxidizers
50[deg]F lower than the average temperature during testing.
With regard to RCO, we agree with the commenters that when the THC
concentration in the inlet is high, the RCO will not need any
additional heat and it can operate at temperatures higher than the set
point. Therefore, if the initial compliance tests are conducted under
these conditions, the operating temperature limit will be too
[[Page 45978]]
high for production rates at less than full capacity. However, the
final rule requires emissions testing under representative operating
conditions and not maximum operating conditions. In addition, we do not
agree with the commenter's solution to set the operating limit at
100[deg]F above the minimum operating (design) temperature of the
catalyst. As with RTO, we feel it is incumbent upon the facility to
demonstrate performance and establish the operating limits during the
compliance demonstration test. Therefore, the final rule requires the
facility to establish the minimum catalytic oxidizer operating
temperature during the compliance test. However, as noted below, we
have provided more flexibility to the facility regarding temperature
monitoring for RTO and RCO.
We recognize that in a typical RTO and RCO the combustion chamber
contains multiple burners, and that each of these burners may have
multiple thermocouples for measuring the temperature associated with
that burner. The final rule requires establishing and monitoring a
minimum firebox temperature for RTO. In an RTO, the minimum firebox
temperature is actually represented by multiple temperature
measurements for multiple burners within the combustion chamber. Thus,
the final rule clarifies that facilities operating RTO may monitor the
temperature in multiple locations within the combustion chamber and
calculate the average of the temperature measurements to use in
establishing the minimum firebox temperature operating limit.
Regarding RCO, we agree with the commenters that, because the gas
flow reverses direction in RCO, the inlet temperature monitor will not
consistently measure the gas at the same point in the process, such
that sometimes the gas temperature will be recorded after the catalyst
beds instead of at the inlet to the beds. We did not intend to require
the separate measurement of each inlet temperature by switching the
data recording back and forth to coincide with the flow direction into
the bed. The intention is to monitor the minimum temperature of the gas
entering the catalyst to ensure that the minimum temperature is
maintained at the operating level during which compliance was
demonstrated. This can be accomplished by measuring the temperature in
the regenerative canisters at one or more locations. Measuring the
inlet temperatures of each catalyst bed and then determining the
average temperature for all catalyst beds is one approach. Even though
some of the beds are cooling and others are heating, the average across
all of the catalyst beds should not vary significantly. Another
acceptable alternative is monitoring the combustion chamber
temperature, as suggested by the commenters. The monitoring location(s)
selected by the facility may depend on the operating conditions (i.e.,
THC loading to the unit) during the performance test and how the unit
is expected to be operated in the future. The objective is to establish
monitoring and operating limits that are representative of the
conditions during the compliance demonstration test(s) and
representative of the temperature to which the catalyst is exposed. We
recognize the need for flexibility in selecting the temperature(s) to
be monitored as operating limits for RCO. Therefore, the final rule
provides flexibility by allowing facilities with RCO to choose between
basing their minimum RCO temperature limit on the average of the inlet
temperatures for all catalyst beds or the average temperature within
the combustion chamber. If there are multiple thermocouples at the
inlet to each catalyst bed, then we would expect facilities to average
the measurements from each thermocouple to provide a representative
catalyst bed inlet temperature for each individual catalyst bed.
Finally, the final rule also includes an option (in lieu of
monitoring oxidizer temperature) for monitoring and maintaining the
oxidizer outlet THC concentration at or below the operating limit
established during the performance test. Use of the THC monitoring
option would eliminate the concerns regarding establishing and
monitoring oxidizer operating temperatures (in effect, it provides
facilities complete flexibility in operation of the control device, as
long as the THC outlet concentration remains below the operating limit).
Comment: One commenter recommended that we require sampling and
testing of the catalyst activity level for RCO. The commenter stated
that the proposed requirement to monitor inlet pressure may not be
sufficient to detect catalyst problems such as poisoning, blinding, or
degradation.
Response: We agree with the commenter that a catalyst activity
level check is needed because catalyst beds can become poisoned and
rendered ineffective. An activity level check can consist of passing an
organic compound of known concentration through a sample of the
catalyst, measuring the percentage reduction of the compound across the
catalyst sample, and comparing that percentage reduction to the
percentage reduction for a fresh sample of the same type of catalyst.
Generally, the PCWP facility would remove a representative sample of
the catalyst from the catalytic oxidizer bed and then ship the sample
to a testing company for analysis of its ability to oxidize organic
compounds (e.g., by a flame ionization detector).
In response to this comment, we added to the final rule a
requirement for facilities with catalytic oxidizers to perform an
annual catalyst activity check on a representative sample of the
catalyst and to take any necessary corrective action to ensure that the
catalyst is performing within its design range. Corrective actions may
include washing or baking out the catalytic media, conducting an
emissions test to ensure the catalytic media is resulting in the
desired emissions reductions, or partial or full media replacement.
Catalysts are designed to have an activity range over which they will
reduce emissions to the desired levels. Therefore, the final rule
specifies that corrective action is needed only when the catalyst
activity is outside of this range. It is not our intention for
facilities to replace catalyst if the catalytic media is not performing
at the maximum level it achieved when the catalyst was new. Also, the
final rule specifies that the catalyst activity check must be done on a
representative sample of the catalyst to ensure that facilities that
may have recently conducted a partial media replacement do not sample
only the fresh catalytic media for the catalyst activity check.
Comment: Several commenters stated that the proposed operating
requirements for pressure drop across the biofilter bed should be
removed from the final PCWP rule. The commenters contended that
pressure drop is a good parameter to monitor voluntarily because it
indicates the permeability and age of the biofilter bed, helping to
determine maintenance and replacement needs; however, it is not an
indicator of destruction efficiency. The commenters noted that, because
of normal wear and tear, the pressure drop gradually increases over the
2- to 5-year life span of the biofilter, so it would not be possible to
maintain a constant operating pressure. The commenters further noted
that the supporting materials in the project docket did not provide any
information or data that would support the idea that pressure drop is
an indication of HAP destruction efficiency, but only indicated that
pressure drop was an indication of the age of the biofilter. For these
reasons, the commenters argued
[[Page 45979]]
that setting an absolute limit on pressure drop was inappropriate.
The commenters also requested that the proposed requirements to
monitor the pH of the biofilter bed effluent be removed from the final
PCWP rule. The commenters noted that pH is a good parameter to monitor
voluntarily because it indicates the environmental conditions inside
the biofilter bed and can indicate the presence of organic acids and
THC decomposition products, but it is not a reliable indicator of
destruction efficiency. According to the commenters, small fluctuations
of pH are expected and have little effect on the biofilter performance;
therefore, the narrow range of pH values that would be established as
an operating range by the initial compliance tests should not be used
alone to determine biofilter performance. The commenters also noted
some problems associated with continuous measurement of pH. According
to the commenters, some biofilter units operate with periodic
irrigation of the bed, such that the effluent flow is not constant and
continuous monitoring is not possible. The commenters also pointed to
an NCASI survey that confirmed that continuous pH monitoring would be
impractical for the facilities surveyed. The commenters stated that,
because none of the PCWP facilities surveyed could find a link between
pH alone and biofilter performance, none of those facilities currently
have continuous pH monitors on their biofilters.
In addition, several commenters requested changes to the proposed
requirement to monitor the inlet temperature of the biofilter. These
commenters agreed that temperature is a parameter that should be
monitored for biofilters, but argued that the location of the
temperature monitor should be changed from the biofilter inlet to the
biofilter bed or biofilter outlet. The commenters noted that the
biofilter bed temperature has the greatest impact on biological
activity. According to the commenters, the biofilter inlet temperature
is not a good indicator of bed temperature and can change very rapidly
depending upon the operating rate of the press, the humidity, and the
ambient temperature.
Response: We agree with the commenters that increases in pressure
drop will occur over time and will not necessarily equate to a
reduction in control efficiency, making an absolute limit on pressure
drop ineffective in demonstrating continuous compliance. Therefore, we
have not included the requirement to monitor pressure drop in the
operating requirements for biofilters in the final PCWP rule. We have
also removed the requirement to monitor pH from the final rule.
Although pH is an indicator of the health of the microbial population
inside the biofilter, we agree with the commenters that including
continuous pH monitoring as an operating requirement for biofilters may
not be appropriate.
We also agree with the commenters that the biofilter bed
temperature has the greatest impact on biological activity and that the
location for monitoring the biofilter temperature should be changed. We
did not propose monitoring of biofilter bed temperature because we
thought that monitoring of biofilter inlet temperature would be simpler
because only one thermocouple would be required. The temperature inside
the biofilter bed can change in different areas of the bed, and
therefore, depending on the biofilter, multiple thermocouples may be
necessary to get an accurate picture of the temperature conditions
inside the biofilter bed. Prior to proposal we rejected the idea of
monitoring the biofilter exhaust temperature because temperature
measured at this location can be affected by ambient temperature
(especially for biofilters with short stacks) more than the temperature
inside the biofilter bed. We now conclude that there is no better, more
representative way to monitor the temperature to which the biofilter
microbial population is exposed than to directly monitor the
temperature of the biofilter bed. According to our MACT survey data,
most facilities with biofilters are already monitoring biofilter bed
temperature. Therefore, the final rule requires continuous monitoring
of the temperature inside the biofilter bed.
The proposed rule would have allowed facilities to specify their
own monitoring methods, monitoring frequencies, and averaging times for
the proposed biofilter operating parameters (i.e., inlet temperature,
effluent pH, and pressure drop). However, monitoring of temperature is
not as subjective as monitoring biofilter effluent pH and pressure
drop; therefore, as an outgrowth of our decision to not require
monitoring of biofilter effluent pH and pressure drop, the final rule
specifies the monitoring method, frequency, and averaging time for
biofilter bed temperature monitoring. The final rule requires that each
thermocouple be placed in a representative location and clarifies that
multiple thermocouples may be used in different locations within the
biofilter bed. The temperature data (i.e., average temperature across
all the thermocouples located in the biofilter bed if multiple
thermocouples are used) must be monitored continuously and reduced to a
24-hour block average. A 24-hour block average was selected for
biofilter temperature monitoring because we recognize that there may be
some diurnal variation in temperature. Facilities wishing to reflect a
diurnal temperature variation when establishing their biofilter
temperature may wish to perform some test runs during peak daily
temperatures and other test runs early in the morning, when
temperatures are at their lowest.
Facilities may choose to observe parameters other than biofilter
bed temperature, but will not be required to record or control them for
the final PCWP rule. We feel that many factors can affect biofilter
performance, either alone (e.g., a media change) or in concert with one
another (e.g., a loss of water flow results in a sharp change in
temperature and pH). The factors that have the greatest effect on
biofilter performance are likely to be site-specific. However, based on
the comments we have received, we conclude that extensive biofilter
parameter monitoring is not the best method for ensuring continuous
compliance. To promote enforceability of the final PCWP rule, we have
added a requirement to perform periodic testing of biofilters. The
final rule requires facilities to conduct a repeat test at least every
2 years and within 180 days after a portion of the biofilter bed is
replaced with a new type of media or more than 50 percent (by volume)
of the biofilter media is replaced with the same type of media. Each
repeat test must be conducted within 2 years of the previous test
(e.g., 2 years after the initial compliance test, or 2 years after the
test following a media change). We are requiring repeat testing after a
partial or wholesale change to another media type (considered a
modification of the biofilter) because such a modification can impact
the performance of the biofilter. Facilities that replace biofilter
media with a new type of media (e.g., bark versus synthetic media) must
also re-establish the limits of the biofilter bed temperature range. We
feel that substantial replacement of the biofilter media (e.g.,
replacement of more than 50 percent of the media) with the same type of
media may affect short-term performance of the biofilter while the
replacement media becomes acclimated, and therefore, the final rule
requires a repeat performance test following this type of media
replacement. However, PCWP facilities that replace biofilter media with
the same type of media are not required to re-establish the biofilter
[[Page 45980]]
bed temperature range. In the case of same-media replacements, we feel
it is appropriate for PCWP facilities to be able to use data from
previous performance tests to establish the limits of the temperature
range. During repeat testing following replacement with the same type
of media, facilities can verify that the biofilter remains within the
temperature range established previously or establish a new compliant
temperature range. Facilities using a THC CEMS that choose to comply
with the THC compliance options (i.e., 90 percent reduction in THC or
outlet THC concentration less than or equal to 20 ppmvd) may use the
data from their CEMS in lieu of conducting repeat performance testing.
Comment: Several commenters requested that the final rule allow new
biofilters a longer period than 180 days to establish operating
parameter levels. These commenters suggested a 1-year period, because
that would be long enough to observe the full seasonal variation in
parameters and find the true operating maxima and minima.
Response: We disagree that more than 180 days is necessary to
establish operating parameter limits for biofilters. As mentioned
previously, we have eliminated the proposed requirement to establish
operating limits for pH and pressure drop. Today's final rule contains
two options for biofilter operating parameter limits: biofilter bed
temperature range and outlet THC concentration. While allowing 1 year
to establish the biofilter bed temperature operating range is
reasonable due to seasonal temperature variations, 1 year is not
necessary for establishing an outlet THC concentration limit.
Furthermore, the final rule already allows facilities to expand their
operating ranges (see Sec. 63.2262(m)(3)) through additional emissions
testing.
The compliance date for existing facilities is 3 years after
promulgation of the final PCWP rule, and existing facilities are
allowed 180 days following the compliance date to conduct performance
testing and establish the operating parameter limits. If there is
concern that 180 days is not long enough for a new biofilter
installation to operate under the full range of biofilter bed
temperatures, then existing facilities should begin operation of their
biofilter well before the compliance date (e.g., 180 days prior to the
compliance date if 1 year is needed). Facilities also have the option
of testing their biofilter prior to the compliance date to establish
one extreme of their biofilter bed temperature range. The compliance
date for new PCWP facilities is the effective date of the rule (if
startup is before the effective date) or upon initial startup (if the
initial startup is after the effective date of the rule), and
biofilters installed at new PCWP facilities would have up to 180 days
following the compliance date to establish the operating parameter
limits. To address situations where a new biofilter is installed at an
existing facility more than 180 days after the compliance date (e.g.,
to replace an existing RTO), we have included section Sec.
63.2262(m)(2) to the final PCWP rule, which allows existing sources
that install new biofilters up to 180 days following the initial
startup date of the biofilter to establish the operating parameter
limits. Thus, new biofilter installations are given time for
establishment of operating parameter limits regardless of where they
are installed at new or existing sources.
Comment: Multiple commenters supported the option to continuously
monitor THC at control device outlets to demonstrate compliance, but
suggested that either the procedure for determining the operating
limits or the length of the averaging periods be altered. The
commenters stated that THC concentration at a control device outlet is
not a parameter that can be easily adjusted by operators over short
periods of time. The commenters stated that 3 hours is not a long
enough block to avoid deviations from compliance given the variability
of the process. The commenters provided an analysis of THC data from a
biofilter outlet that showed multiple deviations occurring over a two
month period when a 3-hour block average was used and few to zero
deviations when a 24-hour or 7-day block average was used for the
operating limits. The commenters stated that because HAP destruction
efficiency of biofilters does not vary much with time, the longer block
average would not be environmentally harmful.
Response: While THC emissions at the outlet of a biofilter may
vary, the THC emissions at the outlet of a thermal or catalytic
oxidizer should not vary greatly. Although, as stated by the
commenters, the HAP destruction efficiency of biofilters is not subject
to large short-term variations, the same is not true for thermal and
catalytic oxidizers (e.g., a sudden significant decrease in temperature
could result in a sudden decrease in HAP reduction). Therefore, we feel
it is appropriate to maintain the 3-hour block averaging requirement
for THC monitoring for thermal and catalytic oxidizers. However, we
have expanded the THC averaging requirement for biofilters to a 24-hour
block average to provide more flexibility. The THC operating limit for
biofilters would be established as the maximum of three 15-minute
recorded readings during emissions testing. We also note the continuous
monitoring of THC is not required for all APCD, but is an alternative
to continuous monitoring of temperature. Furthermore, facilities can
conduct multiple performance tests at different operating conditions to
increase their maximum THC concentration operating limit.
6. Selection of Monitoring Requirements for Uncontrolled Process Units
Comment: Several commenters recommended that we change the title of
proposed Sec. 63.2262(n) (How do I conduct performance tests and
establish operating requirements?--Establishing uncontrolled process
unit operating requirements) to ``Establishing operating requirements
for production-based compliance option process units'' for the final
rule. The commenters stated that the proposed title implied that no
controls of any kind are being applied to these process units, when in
fact facilities may be using P2 techniques to reduce emissions. The
commenters also objected to wording within the proposed section that
suggests that temperature is the only parameter affecting HAP emissions
from the process units. The commenters suggested that the requirements
be revised in the final rule to give sources more flexibility in
identifying and documenting those process unit operating parameters
that are critical to maintaining compliance with the PBCO limits.
Response: At proposal, our intention was to establish operating
requirements for those process units complying with rule requirements
without the use of an APCD. There are two situations in the PCWP rule
as proposed where process units may not have an add-on control device:
(1) When process units meet the PBCO, or (2) when process units used to
generate emissions averaging debits do not have an add-on APCD that
partially controls emissions. To clarify this for the final rule and to
address the commenters' concern regarding applicability of Sec.
63.2262(n), we changed the title of the section to ``Establishing
operating requirements for process units meeting compliance options
without a control device.''
We agree with the commenters that temperature alone is not
necessarily the sole factor affecting HAP emissions from some process
units. A variety of factors can affect HAP emissions, and the
controlling parameter for one process unit may be different than the
controlling parameter for another process unit. Therefore, the final rule
[[Page 45981]]
gives sources more flexibility in selecting and establishing operating
limits for process units without add-on controls. The final rule
requires facilities to identify and document the operating parameter(s)
that affect HAP emissions from the process unit and to establish
appropriate monitoring methods and monitoring frequencies. We recognize
that it is not practical to continuously monitor every process-unit-
specific factor that could affect uncontrolled emissions (e.g., there
is no way to monitor and determine a 3-hour block average of wood
species mix for a particleboard plant). However, some parameters are
suitable for continuous monitoring (e.g., process operating
temperature, furnish moisture content) and are already monitored as
part of normal operation but not for compliance purposes. We feel that
daily records of most parameters would be sufficient to ensure ongoing
compliance (e.g., daily average process operating temperature, furnish
moisture, resin type, wood species mix) if the parameters do not
deviate from the ranges for these parameters during the initial
compliance test. Therefore, in the final PCWP rule, we have replaced
the proposed 3-hour block average temperature monitoring requirements
for process units without control devices with a requirement to
maintain, on a daily basis, the process unit operating parameter(s)
within the ranges established during the performance test. This gives
facilities the flexibility to decide which parameters they will monitor
and control, while providing enforcement personnel with records that
can be used to assess and compare the day-to-day operation of the
process unit to the controlling operating parameters. Facilities are
also allowed to decide for each parameter the appropriate monitoring
methods, monitoring frequencies, and averaging times (not to exceed 24
hours for continuously monitored parameters such as temperature and
wood furnish moisture). Also, to ensure that the HAP emissions measured
during the compliance tests are representative of actual emissions, the
final rule requires testing at representative operating conditions, as
defined in the rule.
7. Data Collection and Handling
Comment: Several commenters requested clarifications and changes to
the proposed requirements related to data collection and handling for
CPMS. The commenters stated that the requirement that a valid hour of
data must include at least three equally spaced data values for that
hour is ambiguous and should be revised. The commenters recommended
that the final rule require facilities to average at least three data
points taken at constant intervals, provided the interval is less than
or equal to 15 minutes. The commenters further noted that a better
approach would be to drop the concept of an hourly average altogether
and simply calculate the block average as the average of all evenly
spaced measurements in the block period with a maximum measurement
interval of 15 minutes. The commenters also noted that the proposed
rule did not specify how to calculate the 3-hour block average when one
or more of the individual hours does not contain at least three valid
data values.
Commenters also requested that the final rule consolidate and
clarify the requirements in proposed Sec. Sec. 63.2268 and 63.2270
regarding data that should be excluded from block averages. The
commenters recommended that the final rule explicitly state that any
monitoring data taken during periods when emission control equipment
are not accepting emissions from the production processes should be
excluded from hourly or block averages. The commenters also noted
inconsistencies in the proposed rule language that seemed to imply that
data collected during production downtime and SSM events would be
included in the hourly averages but not in the block averages. The
commenters stated that, because SSM events occur when the process is
not in operation, there is no need to collect data from these periods.
Response: We agree with the commenters that the proposed rule
language regarding acceptable data and data averaging was somewhat
ambiguous and have revised the language accordingly. Following the
commenters' recommendation, we removed the concept of an hourly average
from the final rule to allow block averages to be calculated as the
average of all evenly spaced measurements in the 3-hour or 24-hour
block period with a maximum measurement interval of 15 minutes. In
place of the requirement for a valid hourly average to contain at least
three equally spaced data values for that hour, we added a minimum data
availability requirement. The minimum data availability requirement
specifies that to calculate data averages for each 3-hour or 24-hour
averaging period, you must have at least 75 percent of the required
recorded readings for that period using only recorded readings that are
based on valid data. The minimum data availability requirement appears
in Sec. 63.2270(f) of today's final rule. To clarify what constitutes
valid data and how to calculate block averages, we rearranged proposed
Sec. Sec. 63.2268 and 63.2270. We moved proposed Sec. 63.2268(a)(3)
and (4) to final Sec. 63.2270 (now Sec. 63.2270(d) and (e)) of
today's final rule. Rather than repeating which data should be excluded
from data averages in Sec. 63.2270(d) and (e), these new sections now
refer to Sec. 63.2270(b) and (c) when discussing data that should not
be included in data averages. We also added data recorded during
periods of SSM to the list of data that should be excluded from data
averages in Sec. 63.2270. We feel these changes to the structure and
wording of the rule should fully address the commenters' concerns.
Comment: Several commenters noted that the proposed PCWP rule does
not provide any alternatives to the definition of a 1-hour period found
in the MACT general provisions (40 CFR 63.2), which states that a 1-
hour period is any 60-minute period commencing on the hour. These
commenters requested that facilities be given the option of beginning a
1-hour period at a time that is convenient depending on shift changes,
employee duties at the end of a shift, and settings on the systems that
record data.
Response: We agree with the commenters and have included a
definition of 1-hour period in today's final rule that omits the phrase
``commencing on the hour.''
8. Performance Specifications for CPMS
Comment: Several commenters requested that we write sections of the
final rule language that address temperature measurement. The
commenters stated that the phrase ``minimum tolerance of 0.75
percent,'' found in proposed sections 63.2268(b)(2), 63.2268(c)(3), and
63.2268(e)(2), should be revised to read ``accurate within 0.75 percent
of sensor range.'' The commenters argued that, because tolerances
usually refer to physical dimensions, this revision more accurately
reflects the intent of the final PCWP rule. Commenters also recommended
that the sensitivity for chart recorders be changed from a sensitivity
in the minor division of at least 20[deg]F to minor divisions of not
more than 20[deg]F. The commenters noted that the wording in the
proposed rule means that minor divisions could be 30[deg]F or 50[deg]F,
but assumed that we probably meant that 20[deg]F is the largest minor
division that a facility can use, and therefore, stated that the
suggested revision is more accurate.
Response: We agree that the proposed temperature measurement
requirements should be clarified. In today's final rule,
[[Page 45982]]
we wrote the requirement in Sec. 63.2269(b)(2) (formerly proposed
Sec. 63.2268(b)(2)) to read ``minimum accuracy of 0.75 percent of the
temperature value.'' We eliminated proposed sections Sec. Sec.
63.2268(c) and 63.2268(e) from the final rule because we removed the
requirements for monitoring of pressure or flow. We also wrote proposed
Sec. 63.2268(b)(3) to state that ``If a chart recorder is used, it
must have a sensitivity with minor divisions of not more than
20[deg]F.''
Comment: Several commenters requested changes to the proposed work
practice requirements for dry rotary dryers and veneer redryers related
to moisture monitoring. The commenters noted that the proposed
requirement to use a moisture monitor with a minimum accuracy of 1
percent was appropriate for rotary dry dryers in the 25 to 35 percent
moisture content range. However, the commenters stated that less
stringent accuracy requirements should be included for veneer redryers
to better correspond with current practices at softwood plywood and
veneer facilities. Specifically, the commenters requested that the
final rule revise the proposed performance specifications for moisture
monitors for veneer redryers to allow the use of monitors with an
accuracy of 3 percent in the 15 to 25 percent moisture
range. Several commenters also requested that the proposed calibration
procedures for moisture monitors be revised in the final rule to
eliminate grab sampling and to allow facilities to follow the
calibration procedures recommended by the manufacturer. The commenters
argued that the proposed grab sampling procedure is impractical and
that obtaining a representative grab sample would be difficult.
Response: We agree with the commenters that the proposed moisture
monitoring requirements should be adjusted in the final rule and have
made the requested changes to the accuracy requirements for moisture
monitors used with rotary dry dryers and veneer redryers. We have also
adjusted the calibration procedures in the final rule to eliminate grab
sampling and to allow facilities to follow the manufacturer's
recommended calibration procedures for moisture monitors.
I. Routine Control Device Maintenance Exemption (RCDME)
Comment: Several commenters requested that the proposed
requirements for the RCDME be modified in the final rule to give PCWP
facilities more flexibility. First, the commenters requested that the
proposed RCDME allowances (expressed as a percentage of the process
unit operating hours) be increased. The commenters argued that the
proposed downtime allowance periods are too short to allow for proper
maintenance. The commenters noted that the NCASI survey that was used
to set the downtime allowance only included data from 1999, and many
facilities may have conducted nonannual maintenance and repairs in the
years preceding or following that year. According to the commenters,
the 1999 survey was also limited in that the majority of the RTO
included in the survey were less than 5 years old, and as the equipment
ages over a lifetime of 5 to 15 years, performance will degrade below
the levels seen in the 1999 survey. Therefore, the commenters suggested
that we reexamine the NCASI downtime data and use the 79th percentile
instead of the 50th percentile to select downtime allowances that
represent the time needed for nonannual events.
Response: After reviewing our previous analysis of the downtime
data, we maintain that the percentage downtime we proposed (3 percent
for some process units and 0.5 percent for others) calculated on an
annual basis is appropriate for the final PCWP rule. The downtime
allowance allowed under the RCDME is intended to allow facilities
limited time to perform routine maintenance on their APCD without
shutting down the process units being controlled by the APCD. We
included the downtime allowance in the proposed rule because we
recognize that frequent maintenance must be performed to combat
particulate and salt buildup in some RTO and RCO for PCWP drying
processes. The downtime allowance is not intended to cover every APCD
maintenance activity, only those maintenance activities that are
routine (e.g., bakeouts, washouts, partial or full media replacements)
and do not coincide with process unit shutdowns. Most APCD maintenance
should occur during process unit shutdowns; the RCDME is a downtime
allowance in addition to the APCD maintenance downtime that occurs
during process unit shutdowns. We note that most PCWP plants do not
operate 8,760 hours per year without shutdowns. For example, the MACT
survey responses indicate that softwood plywood plants operate for an
average 7,540 hours per year, which would allow 1,220 hours for control
device maintenance without the RCDME. Furthermore, the RCDME is allowed
in addition to APCD downtime associated with SSM events covered by the
SSM plan (e.g., electrical problems, mechanical problems, utility
supply problems, and pre-filter upsets). For these reasons, the final
rule retains the RCDME allowances included in the proposed rule.
Comment: Several commenters objected to the proposed requirement
that the maintenance be scheduled at the beginning of the semiannual
period. The commenters argued that scheduling maintenance activities at
the beginning of each semiannual period is neither consistent with
industry practice nor practical. The commenters noted that downtime for
maintenance is scheduled as the need arises, and downtime schedules
change with need and production requirements. The commenters stated
that most facilities have a general idea of when they intend to conduct
routine maintenance activities and will schedule those activities
whenever possible to coincide with process downtime as it approaches.
The commenters further noted that the proposed PCWP rule does not
clarify what would happen if maintenance were necessary before the
scheduled date. Therefore, the commenters concluded that deleting the
requirement to set the maintenance schedule at the beginning of each
semiannual period would eliminate confusion and better represent
industry practice.
Response: We agree with the commenters and have removed the
requirement to record the control device maintenance schedule for the
semiannual period from the final rule. We agree that the proposed
requirement would be impractical because process unit shutdowns are not
scheduled semiannually. Also, the SSM provisions do not require
scheduling of maintenance, and therefore, requiring scheduling of
routine maintenance covered under the RCDME would be more restrictive
than the requirements for SSM. To the extent possible, APCD maintenance
should be scheduled at the same time as process unit shutdowns. Thus,
today's final rule retains the requirement that startup and shutdown of
emission control systems must be scheduled during times when process
equipment is also shut down.
Comment: Commenters also requested that the proposed RCDME
requirement that facilities must minimize emissions to the greatest
extent possible during maintenance periods be revised to require that
facilities make reasonable efforts to minimize emissions during
maintenance. The commenters stated that this revision is necessary
because the proposed wording could be interpreted to mean that sources
should limit production or shut down entirely
[[Page 45983]]
during maintenance periods, which is contrary to the intent of the RCDME.
Response: We agree with the commenters and have modified the
referenced requirement as suggested by the commenters.
J. Startup, Shutdown, and Malfunction (SSM)
Comment: Several commenters noted inconsistencies between the
proposed rule and the NESHAP General Provisions (40 CFR part 63,
subpart A) and requested that these inconsistencies be resolved by
making the final PCWP rule consistent with the latest version of the
General Provisions.
Response: Approximately 1 month prior to publication of the
proposed PCWP rule, we published proposed amendments to the NESHAP
General Provisions concerning SSM procedures (67 FR 72875, December 9,
2002) and promulgated them in May 2003 (68 FR 32585, May 30, 2003). Due
to the timing of the these rulemakings, the proposed PCWP rule language
did not reflect our most recent decisions regarding SSM. To avoid
confusion and promote consistency, we have written the final rule to
reference the NESHAP General Provisions directly, where applicable, and
to be more consistent with other recently promulgated MACT standards.
Although the amendments to the NESHAP General Provisions regarding SSM
plans are currently involved in litigation, the rule requirements
promulgated on May 30, 2003, apply to the final PCWP NESHAP unless and
until we promulgate another revision. In response to suggestions made
by commenters, we also consolidated several sections to clarify the
requirements related to SSM and to eliminate redundancies in the final
rule. Specifically, we combined proposed Sec. 63.2250(d) with proposed
Sec. 63.2250(a) and revised the resulting Sec. 63.2250(a) to clarify
that the SSM periods mentioned in proposed Sec. 63.2250(a) apply to
both process units and control devices and to clarify when the
compliance options, operating requirements, and work practice
requirements do and do not apply. We also removed proposed Sec.
63.2250(e) from the final rule because it was a duplication of proposed
Sec. 63.2251(e) regarding control device maintenance schedules. In
addition, we removed proposed Sec. 63.2250(f) related to RCO catalyst
maintenance because this section was misplaced and is not consistent
with the RCO monitoring requirements in today's final rule.
K. Risk-Based Approaches
1. General Comments
Risk-Based Approaches
Comment: Numerous commenters encouraged EPA to incorporate risk-
based options which would exclude facilities that pose no significant
risk to public health or the environment. Commenters stated that
inclusion of risk provisions has the potential to achieve overall
environmentally superior results in a cost-effective manner,
particularly in cases where criteria pollutants from control devices
(i.e., incinerators) may result in greater impacts that the HAP
emissions that they control. In particular, the commenter referred to
EPA's projection that adoption of MACT floor level controls would
result in increased emissions of NOX, a precursor to ozone
and PM. According to the commenter, the proposed rule (without risk
provisions) would work against the industry's voluntary commitment to
reduce the emissions of greenhouse gases by 12 percent over the next 10
years. The commenter concluded that, in its proposed form, the rule
would impose significant additional cost with virtually no gain to
either the environment or the health. The commenter stated that
facilities wishing to take advantage of the risk-based exemption would
take a federally-enforceable permit limit that would guarantee that
their emissions remain below the risk-based emission standard. This
would constitute an emission limitation, within the statutory
definition of the term, and it would allow facilities to forego the
installation of incinerators where they are not warranted by public
health and environmental considerations, the commenter claimed.
Some commenters argued that the risk-based options are legally
justified, protective of human health and the environment, and
economically sensible. These commenters stated that the risk-based
options are supported under the CAA, through EPA's authority under
sections 112(d)(4) and 112(c)(9) to set emission standards other than
MACT for certain low-risk facilities and delist technology-defined low-
risk subcategories, respectively, and through what they claimed is
EPA's inherent de minimis authority to avoid undertaking regulatory
action in the absence of meaningful risk. One commenter pointed out
that, by meeting the stringent health benchmarks necessary to qualify
for the risk-based compliance approaches, facilities already would have
satisfied the residual risk provisions 8 years ahead of the statutory
requirements set forth in section 112(f) of the CAA.
Two commenters believed that the risk-based approach would
particularly benefit small mills located in rural areas with timber-
dependent economies. One commenter stated that, by offering
manufacturers an opportunity to apply for subcategorization on a site-
specific basis, facilities that are remotely located, or which were
originally planned and sited with thorough consideration of airshed
impacts, would not be unduly burdened with MACT requirements which
yield little or no public health benefits.
Some commenters argued that such low-risk facilities should not be
burdened with the requirements of MACT. One commenter noted that the
regulatory framework exists within their State to implement a risk-
based approach. Another commenter agreed with the concept of a risk-
based approach but stated that it would not be appropriate for State
and local programs to determine which facilities should be exempted
from MACT. Another commenter suggested that exemptions be provided on a
case-by-case basis to individual facilities that are able to
demonstrate that they pose no significant risk to public health or the
environment.
Several commenters opposed the risk-based exemptions. Two
commenters stated that the use of risk-based concepts to evade MACT
applicability is contrary to the intent of the CAA and is based on a
flawed interpretation of section 112(d)(4) written by an industry
subject to regulation. One commenter added that the CAA requires a
technology-based floor level of control and does not provide exclusions
for risk or secondary impacts in applying the MACT floor. The other
commenter was concerned about industry's unprecedented proposal to
include de minimis exemptions and cost in the MACT standard process.
The commenter stated that including case-by-case risk-based exemptions
would jeopardize the effectiveness of the national air toxics program
to adequately protect public health and the environment and to
establish a level playing field. A third commenter noted that
subcategorization and source category deletions under CAA section
112(c) have been implemented several times since the MACT program began.
Some commenters pointed out that they have not been able to comment
on the technical merit of the risk analysis employed by the EPA. They
argued that, until the residual risk analysis procedures have been
implemented via the CAA section 112(f) process, risk
[[Page 45984]]
analysis should not be used in making MACT determinations pursuant to
CAA section 112(d)(4). Also, risk analysis could never be used to
establish a MACT floor.
One commenter pointed out that, in separate rulemakings and
lawsuits, EPA adopted legal positions and policies that they claimed
refute and contradict the very risk-based and cost-based approaches
contained in the proposal. In these other arenas, EPA properly rejected
risk assessment to alter the establishment of MACT standards. The EPA
also properly rejected cost in determining MACT floors and in denying a
basis for avoiding the MACT floor.
Response: We feel that the assertions by one commenter about the
environmental disbenefits of the PCWP rule as proposed are overstated.
We disagree that the PCWP industry as a whole poses a small-to-
insignificant risk to human health and the environment. However, we
acknowledge that there are some PCWP affected sources that pose little
risk to human health and the environment. Consequently, we have
included an option in today's final PCWP rule that would allow
individual affected sources to be found eligible for membership in a
delisted low-risk subcategory if they demonstrate that they do not pose
a significant risk to human health or the environment. The low-risk
subcategory delisting in today's final PCWP rule is based on our
authority under CAA sections 112(c)(1) and (9). The statute requires
that categories or subcategories meet specific risk criteria in order
to be delisted. To determine whether source categories and
subcategories, and their constituent sources, meet these criteria, risk
analyses may be used. We disagree with the commenter that we must wait
for implementation of CAA section 112(f) before utilizing risk analysis
in this manner. Section 112(d)(1) of the CAA gives us the authority to
distinguish among classes, types, and sizes of sources within a
category, and CAA section 112(c)(1) does not restrict our authority to
base categories and subcategories on other appropriate criteria. As
discussed in more detail elsewhere in this notice, we feel these
provisions of the CAA allow us to define a subcategory of sources in
terms of risk. Thus, the low-risk subcategory of PCWP affected sources
is defined in terms of risk, not cost. We are not subcategorizing or
determining MACT floors based on cost. Furthermore, because most
affected sources will make their low-risk demonstrations following
promulgation of today's final PCWP rule, the MACT level of emissions
reduction required by today's final rule is not affected by affected
sources becoming part of the low-risk subcategory.
We are not pursuing the risk-based exemptions based on CAA section
112(d)(4). We do not feel that a risk-based approach based on section
112(d)(4) is appropriate for the PCWP industry because PCWP facilities
emit HAP for which no health thresholds have been established and
because the legislative history of the 1990 Amendments to the CAA
indicates that Congress considered and rejected allowing us to grant
such source-specific exemptions from the MACT floor. We also are not
relying on de minimis authority. Legal issues associated with the risk-
based provisions are addressed elsewhere in this preamble.
In today's final PCWP rule, we are identifying the criteria we will
use to identify low-risk PCWP affected sources and requesting that any
candidate affected sources, in addition to the affected sources already
identified as low risk in today's action, submit information to us
based on those criteria so that we can evaluate whether they might be
low-risk. Today's final PCWP rule also establishes a low-risk PCWP
subcategory based on the criteria (and including several identified
affected sources) and delists the subcategory based on our finding that
no source that would be eligible to be included in the subcategory
based on our adopted criteria emits HAP at levels that exceed the
thresholds specified in section 112(c)(9)(B) of the CAA. To be found
eligible to be included in the delisted source category, affected
sources will have to demonstrate to us that they meet the criteria
established by today's final PCWP rule and assume federally enforceable
limitations that ensure their HAP emissions do not subsequently
increase to exceed levels reflected in their eligibility demonstrations.
The criteria defining the low-risk subcategory of PCWP affected
sources are included in appendix B to subpart DDDD of 40 CFR part 63.
The criteria in the appendix were developed for and apply only to the
PCWP industry and are not applicable to other industries. Today's final
PCWP rule provides two ways that an affected source may demonstrate
that it is part of the low-risk subcategory of PCWP affected sources.
First, look-up tables allow affected sources to determine, using a
limited number of site-specific input parameters, whether emissions
from their sources might cause a hazard index (HI) limit for
noncarcinogens or a cancer benchmark of one in a million to be
exceeded. Second, a site-specific modeling approach can be used by
those affected sources that cannot demonstrate that they are part of
the low-risk subcategory using the look-up tables.
The low-risk subcategory delisting that is included in today's
final PCWP rule is intended to avoid imposing unnecessary controls on
affected sources that pose little risk to human health or the
environment. Facilities will have to select controls or other methods
of limiting risk and then demonstrate, using appendix B to subpart DDDD
of 40 CFR part 63 and other analytical tools, such as the ``Air Toxics
Risk Assessment Reference Library,'' if appropriate in a source's case,
that their emissions qualify them to be included in the low-risk
subcategory, and, therefore, to not be subject to the MACT compliance
options included in today's final PCWP rule.
Comment: Several commenters objected to EPA using the preambles of
individual rule proposals as the forum for introducing significant
changes in the way that MACT standards are established. The commenter
believed that allowing risk-based exemptions requires statutory
changes. A third commenter expressed concern that other parties may
miss commenting on the risk-based exemptions because they are contained
within six separate proposals. The commenter added that to give the
issue full consideration, the risk provisions should not be adopted
within any of the final rules but should be addressed in one place,
such as in revisions to the General Provisions of 40 CFR part 63, subpart A.
Response: The discussion of risk-based provisions in MACT was
included in individual proposals for several reasons. First, we
recognize that such provisions might only be appropriate for certain
source categories, and our decision-making process required source
category-specific input from stakeholders. Second, the 10-year MACT
standards, which are now being completed, are the last group of MACT
standards currently planned for development, and for any risk
provisions to be useful, the provisions must be finalized in a timely
manner. We do not agree that statutory changes are necessary because of
the discretion provided to the Administrator under CAA section
112(d)(1) to distinguish among classes, types, and sizes of sources
within a category and under CAA section 112(c)(1) to base categories
and subcategories on any appropriate criteria. We consider low-risk affected
[[Page 45985]]
sources to be an appropriate subcategory of sources within the PCWP
source category.
Comment: Several commenters stated that the risk-based exemption
proposal removes the level playing field that would result from the
proper implementation of technology-based MACT standards. According to
the commenters, establishing a baseline level of control is essential
to prevent industry from moving to areas of the country that have the
least stringent air toxics programs, which was one of the primary goals
of developing a uniform national air toxics program under section 112
of the 1990 CAA amendments. The commenters argued that risk-based
approaches would jeopardize future reductions of HAP in a uniform and
consistent manner across the nation. One commenter stated that National
Air Toxics Assessment (NATA) data show that virtually no area of the
country has escaped measurable concentrations of toxic air pollution.
The NATA information indicates that exposure to air toxics is high in
both densely populated and remote rural areas.
One commenter disagreed with the assertion that the level playing
field would be removed. The commenter pointed out that the argument
that EPA should impose unnecessary and potentially environmentally
damaging controls for the sole purpose of equalizing control costs
across facilities would be at odds with the stated purpose of the CAA.
According to the commenter, the claim that the risk-based approach
would favor facilities located away from population centers is
incorrect. As contemplated, the risk-based approaches to the NESHAP
would be keyed to the comparison of health benchmarks with reasonable
maximum chronic and acute exposures. According to the commenter, the
presence or absence of human populations would have no effect on
whether facilities would qualify.
Response: We agree that one of the primary goals of developing a
uniform national air toxics program under section 112 of the 1990 CAA
amendments was to establish a level playing field. We do not feel that
defining a low-risk subcategory in today's final PCWP rule does
anything to remove the level playing field for PCWP facilities. Today's
final PCWP rule and its criteria for demonstrating eligibility for the
delisted low-risk subcategory apply uniformly to all PCWP facilities
across the nation. Today's final PCWP rule establishes a baseline level
of emission reduction or a baseline level of risk (for the low-risk
subcategory). All PCWP affected sources are subject to these same
baseline levels, and all facilities have the same opportunity to
demonstrate that they are part of the delisted low-risk subcategory.
The criteria for the low-risk subcategory are not dependent on local
air toxics programs. Therefore, concerns regarding facilities moving to
areas of the country with less-stringent air toxics programs should be
alleviated.
Although NATA may show measurable concentrations of toxic air
pollution across the country, these data do not suggest that PCWP
facilities that do not contribute to the high exposures and risk should
be included in MACT regulations, notwithstanding our authority under
CAA section 112(c)(9).
Comment: One commenter stated that the dockets for the MACT
proposals that contain the risk approaches make it clear that the White
House Office of Management and Budget (OMB) and industry were the
driving forces behind the appearance of these unlawful approaches in
EPA's proposals. The commenter condemned the industry-driven agenda
that it claimed is being promoted by the White House OMB.
A second commenter stated that the accusations that EPA succumbed
to industry lobbying and internal pressures are entirely unfounded.
Response: We are required by Executive Order 12866 to submit to OMB
for review all proposed and final rulemaking packages that would have
an annual effect on the economy of $100 million or more. The comments
we received from OMB reflect their position that low-risk facilities do
not warrant regulation. However, the commenter is incorrect in implying
that we have not exercised our independent judgment in addressing these
issues. Our rationale for adopting the risk-based approach in this PCWP
rulemaking is that such an approach is fully authorized under the CAA.
This rule reflects the EPA Administrator's appropriate use of
discretion to use CAA section 112(c)(9) to delist a low-risk subcategory.
Effects on MACT Program
Comment: Several commenters expressed concern about the impact of a
risk-based approach on the MACT program. Some commenters stated that
the proposal to include risk-based exemptions is contrary to the 1990
CAA Amendments, which calls for MACT standards based on technology
rather than risk as a first step. The commenters pointed out that
Congress incorporated the residual risk program under CAA section
112(f) to follow the MACT standards, not to replace them. One commenter
added that risk-based approaches would be used separately to augment
and improve technology-based standards that do not adequately provide
protection to the public.
Another commenter believed that CAA section 112(d)(4) and the
regulatory precedent established in over 80 MACT standards reject the
inclusion of risk in the first phase of the MACT standards process. The
commenter argued that the use of risk assessment at this stage of the
MACT program is, in fact, directly opposed to title III of the CAA.
Response: We disagree that inclusion of a low-risk subcategory in
today's final PCWP rule is contrary to the 1990 CAA Amendments. The
PCWP MACT rule is a technology-based standard developed using the
procedures dictated by section 112 of the CAA. The only difference
between today's final PCWP rule and other MACT rules is that we used
our discretion under CAA sections 112(c)(1) and (9) to subcategorize
and delist low-risk affected sources, in addition to fulfilling our
duties under CAA section 112(d) to set MACT. The CAA requires that
categories or subcategories meet specific risk criteria, and to
determine this, risk analyses may be used. We disagree with the
commenter that we must wait for implementation of CAA section 112(f)
before utilizing risk analysis in this manner. We feel that today's
final PCWP rule is particularly well-suited for a risk-based option
because of the specific pollutants that are emitted by PCWP sources.
For many affected sources, the pollutants are emitted in amounts that
pose little risk to the surrounding population. However, the cost of
controlling these pollutants is high, and may not be justified by
environmental benefits for these low-risk affected sources. Only those
PCWP affected sources that demonstrate that they are low risk are
eligible for inclusion in the delisted low-risk subcategory. The
criteria included in today's final PCWP rule defining the delisted low-
risk subcategory are based on sufficient information to develop health-
protective estimates of risk and will provide ample protection of human
health and the environment.
Inclusion of a low-risk subcategory in today's final PCWP rule does
not alter the MACT program or affect the schedule for promulgation of
the remaining MACT standards. We recognize that such provisions are
only appropriate for certain source categories, and our decision-making
process required source category-specific input from stakeholders. The
10-year MACT standards, which are now being completed, are the last group
[[Page 45986]]
of MACT standards currently planned for development, and for any risk
provisions to be useful, the provisions must be finalized in a timely
manner.
Comment: Several commenters stated that the inclusion of a risk-
based approach would delay the MACT program and/or promulgation of the
PCWP MACT standard. If the proposed approaches are inserted into
upcoming standards, the commenters feared the MACT program (which is
already far behind schedule) would be further delayed.
One commenter stated that they were strongly opposed to returning
to the morass of risk-based analysis in an attempt to preempt the
application of technology-based MACT standards and exempt facilities.
The commenter stated that designing a risk-based analysis procedure
would also take significant resources, as evidenced by the fact that it
took five plus pages in the Federal Register to discuss just the basic
issues to be considered in the analysis. The commenter indicated that
the demand on government resources could cause a delay in the
application of MACT nationwide. The commenter stated that EPA should
also consider the issue of fairness since the rest of the industrial
sector whose NESHAP have already been promulgated did not have a risk-
based option.
Another commenter stated that it is evident that the proposed risk-
based exemptions would require extensive debate and review in order to
launch, which would further delay promulgation of the remaining MACT
standards. The commenter stated that delays could be exacerbated by
litigation following legal challenges to the rules, and such delays
would trigger the CAA section 112(j) MACT hammer provision, which would
unnecessarily burden the State and local agencies and the industries.
The commenter concluded that, obviously, further delay is unacceptable.
Another commenter agreed, stating that it is imperative that EPA meet
the new deadlines for promulgating the final MACT standards.
Two commenters stated that EPA's proposal to improperly incorporate
risk assessment into the technology-based standard process would
cripple a MACT program already in disarray. The commenters argued that
the risk-based approach could exacerbate the delay in HAP emissions
reductions required by CAA section 112. One commenter noted that EPA's
Office of Inspector General recently found that EPA is nearly 2 years
behind in fulfilling its statutory responsibilities for implementing
Phase 1 MACT standards. According to the commenter, this delay
potentially harms the public and environment. The inclusion of risk-
based exemptions in 10-year MACT standards would only further delay
this process. The other commenter noted that EPA lacks adequate
emissions and exposure data, source characterization data, and health
and ecological effects information to conduct this process anyway. This
commenter believed that the air toxics program is flawed and failing to
protect public health and the environment and argued that it was
irresponsible for EPA to pursue a deregulatory agenda that would
further weaken the effectiveness of the air toxics program. The
commenter noted that EPA acknowledged the complexity and delays
associated with the proposed risk-based approaches in deciding not to
adopt the approaches in the final BSCP rule.
Response: We disagree that identification and delisting of a low-
risk subcategory in today's final PCWP rule will alter the MACT program
or affect the schedule for promulgation of the remaining MACT
standards, especially the PCWP MACT rule. In fact, it has not caused
such a delay for the final rule. We do not anticipate any further
delays in completing the remaining MACT standards. The delisting of a
low-risk subcategory in today's final PCWP rule affects only the PCWP
rule, and not any other MACT standards.
We feel that the final PCWP rule is particularly well-suited for a
risk-based option because of the specific pollutants that are emitted.
For many affected sources, the pollutants are emitted in amounts that
pose little risk to the surrounding population. However, the cost of
controlling these pollutants is high and may not be justified by
environmental benefits for these low-risk facilities. Only those PCWP
affected sources that demonstrate that they are low risk are eligible
for inclusion in the delisted low-risk subcategory. The criteria
defining the delisted low-risk subcategory are based on sufficient
information to develop health-protective estimates of risk and will
provide ample protection of human health and the environment.
The final PCWP NESHAP is being promulgated by the February 2004
court-ordered deadline. Any delays in implementation of the final PCWP
NESHAP caused by legal challenges, which could and often do occur for
any MACT standard we promulgate without a risk-based approach, are
beyond our control.
2. Legal Authority
Section 112(d)(4) of the CAA
Comment: We received multiple comments stating that CAA section
112(d)(4) provides EPA with authority to exclude sources that emit
threshold pollutants from regulation. We also received multiple
comments disagreeing that CAA section 112(d)(4) can be interpreted to
allow exemptions for individual sources. Several commenters supported
the use of a CAA section 112(d)(4) applicability cutoffs for both
threshold and non-threshold pollutants.
Response: We feel that section 112(d)(4) does not give us the
authority to exempt affected sources or emission points from MACT
limitations on non-threshold pollutant emissions. All PCWP facilities
emit carcinogens (e.g., formaldehyde), that are currently considered
non-threshold pollutants. Therefore, we are not using section 112(d)(4)
authority to create risk-based options for PCWP.
We are not setting a risk-based emission limit, but, rather, we are
using our CAA section 112(c)(9) authority to delist affected sources
that demonstrate they meet the risk and hazard criteria for being
included in this low-risk subcategory.
De minimis
Comment: Some commenters attempted to identify a source of
authority for risk-based approaches under the de minimis doctrine
articulated by appellate courts. The commenters cited case law which
they believe holds EPA may exempt de minimis sources of risk from MACT-
level controls because the mandate of CAA section 112 is not
extraordinarily rigid and the exemption is consistent with the CAA's
health-protective purpose. The commenters argued that CAA sections
112(c)(9) and 112(f)(2) indicate that Congress considered a cancer risk
below one in a million to be de minimis and, therefore, insufficient to
justify regulation under section 112. The commenters stated that EPA's
exercise of de minimis authority has withstood judicial challenge, and
that application of de minimis authority is based on the degree of risk
at issue, not on the mass of emissions to be regulated.
Other commenters argued that de minimis authority does not exist to
create MACT exemptions on a facility-by-facility or category-wide
basis. The commenters stated that EPA lacks de minimis authority to
delist subcategories based on risk. The commenters further noted that
EPA has not revealed any administrative record
[[Page 45987]]
justifying a de minimis exemption, to demonstrate that compliance with
MACT would yield a gain of trivial or no value.
Response: We are not relying on de minimis principles for today's
action, and therefore, do not need to respond to these comments.
Section 112(c)(9) of the CAA
Comment: Two commenters opposed using subcategorization as a
mechanism to exempt facilities. One of the commenters stated that
subcategorization is a tool that should be used in the standard setting
process, and using it to exempt facilities would have a detrimental
effect on the stringency of the MACT floor and would generally degrade
the standard. According to the commenter, the two-step
subcategorization proposal is inconsistent with how subcategorization
has been done in numerous previous NESHAP.
The other commenter argued that EPA's subcategorization theories
are unlawful. According to the commenter, CAA section 112(c)(9) does
not authorize EPA to separate identical pollution sources into
subcategories that are regulated differently to weed out low-risk
facilities or reduce the scope/cost of the standard. The commenter
stated that subcategories based solely on risk do not bear a reasonable
relationship to Congress' technology-based approach or the statutory
structure and purposes of CAA section 112, and are not authorized by
the CAA. According to the commenter, categories and subcategories are
required to be consistent with the categories of stationary sources in
CAA section 111. The commenter was not aware of any instance in which
EPA has established categories or subcategories based on risk. The
commenter stated that EPA routinely defines subcategories based on
equipment characteristics (e.g., technical differences in emissions
characteristics, processes, control device applicability, or
opportunities for P2). According to the commenter, EPA has not offered
any explanation for why reinterpreting the statute to ignore nearly 12
years of settled practices and expectations under the MACT program is
reasonable, nor why reducing the applicability of HAP emission
standards serves Congress's goals in enacting the 1990 CAA Amendments.
The commenter noted that EPA's discussion of the risk-based
exemptions was contained in a preamble section entitled, ``Can We
Achieve the Goals of the Proposed Rule in a Less Costly Manner,'' which
strongly suggests that EPA's motivation for considering these risk-
based approaches is consideration of cost. The commenter cited prior
EPA documentation and stated that EPA in the past has rejected the
notion that cost should influence MACT determination, and this prior,
consistently applied interpretation better serves the purposes of CAA
section 112. The commenter argued that subcategorizing to set a no-
control MACT floor is the same as refusing to set a MACT standard
because the benefits would be negligible, which is unlawful.
The commenter also stated that CAA section 112(c)(9)(B)(i) does not
authorize EPA to delist subcategories. According to the commenter,
section 112(c)(9)(B) contains two subsections: subsection (i) refers
only to categories, and subsection (ii) refers to both categories and
subcategories. The commenter argued that the absence of the term
``subcategories'' in section 112(c)(9)(B)(i) indicates a Congressional
choice not to permit the Administrator to delist subcategories of
sources under section 112(c)(9)(B). The commenter stated that this is
consistent with Congress' decision to require a higher standard to
delist categories that emit carcinogens. According to the commenter,
the section 112(c)(9)(B)(ii) requirement of less than one in a million
lifetime cancer risk for the most exposed individual is a higher and
more specific standard than the standard for other HAP.
To the contrary, two commenters stated that EPA has ample authority
under CAA sections 112(c)(1) and 112(c)(9) to create and delist low-
risk categories or subcategories. According to the commenters, section
112(c)(1) provides the Administrator with significant flexibility to
create categories and subcategories as needed to implement CAA section
112. One commenter stated that there is nothing in the statute that
limits the criteria the Administrator can use in establishing
categories and subcategories. The commenter added that there is also
nothing in the history of EPA's interpretation of section 112(c) that
precludes subcategorization based on risk. In addition, EPA has stated
that emission characteristics are factors to be considered when
defining categories.
The commenter stated that application of statutory authority to
exclude sources from regulation under section 112(d)(3) is also
supported by relevant case law, e.g., in the Vinyl Chloride case. (NRDC
v. EPA, 824 F.2D 1126 (D.C. Cir. 1987)) According to the commenter, the
court in that case established a range of acceptable levels of risk in
establishing limits under prior language in section 112, and the
establishment of an acceptable level of risk could be used to create a
low-risk subcategory that could be delisted. The commenter stated that
technological or operational differences among sources may also help
discriminate between low-risk and high-risk sources. The commenter
stated that effective use of section 112(c)(1) authority to create
risk-based subcategories would significantly improve the cost-
effectiveness of the section 112 program without undermining its role
in protecting public health and the environment.
Both commenters noted that CAA section 112(c)(9)(B) provides EPA
with broad authority to remove from MACT applicability those categories
and subcategories of facilities whose HAP emissions are sufficiently
low as to demonstrate a cancer risk less than one in a million to the
most exposed individual in the population (for non-threshold
carcinogens) and no adverse environmental or public health effect (for
threshold HAP). (The commenter asserted that Congress used the terms
category and subcategory interchangeably, indicating that either one
can be delisted.) One commenter suggested that sources able to
demonstrate a basis for inclusion in the delisted category on a case-
by-case basis would then be exempted from the MACT, subject to possible
federally-enforceable conditions designed by EPA. The commenter stated
that the new category could include the following: all low-risk
facilities, facilities producing wood products found to pose no
expected risk to human health (i.e., fiberboard, medium density
fiberboard and plywood), facilities with acrolein emissions below a
certain threshold, or facilities selected on the basis of some other
risk criterion. The commenter suggested that the low-risk category be
included in the final rule and delisted within 6 months following
publication of the final rule. The delisting notices would designate
health benchmarks and facilities would be required to submit evidence
(e.g., tiered dispersion modeling) demonstrating that their emissions
result in exposures that fall below the benchmarks. Following delisting
of the category, an affected source could apply to EPA for a
determination that it qualifies for inclusion in the low-risk category.
After evaluating the source's petition, EPA would issue a written
determination of applicability based on the petition that would be
binding on the permitting authority (unless the petition was found to
contain significant errors or omissions) and appealable by the affected
source or interested parties.
[[Page 45988]]
The EPA could require all facilities that qualify for inclusion in the
delisted category to comply with federally-enforceable conditions,
similar to the conditions established in permits for synthetic minor
sources (e.g., limits on potential to emit, production limits).
The commenter also responded to objections regarding the
subcategorization and delisting of low-risk facilities. The commenter
stated that the contrasting of the terms category and subcategory
offered a distinction that in no way limited EPA's authority to delist
low-risk facilities. According to the commenter, the argument that EPA
cannot create subcategories based on risk is contradicted by the
statutory language, which expressly states that the categories and
subcategories EPA creates under CAA section 112 need not match those
created under CAA section 111. Furthermore, prior EPA statements do
nothing to detract from EPA's broad discretion to establish categories
and subcategories. The subcategorization factors previously discussed
by EPA justify subcategorization based on risk. The authority cited by
one commenter does not establish that EPA's discretion to alter
subcategorization is limited in any way, and even if it were, EPA is
not bound by any prior position. The arguments that EPA may not delist
subcategories for carcinogens (or sources emitting carcinogens) rest on
a formalistic distinction that EPA previously has rejected as
meaningless, and that, at any rate, can be remedied with a simple
recasting of a subcategory as a category. The commenter stated that
doing so is undisputedly within EPA's authority.
Three commenters addressed the issue of subcategorizing PCWP
facilities based on characteristics other than risk. One commenter
stated that the only option that appears consistent with the CAA, does
not create excessive work for State and local agencies, and may be able
to be based on science, is the subcategorization and delisting
approach. However, the commenter added that the subcategories should be
based on equipment or fuel use, not risk. The commenter stated that a
subcategory based on site-specific risk creates a circular definition
and does not make sense. The commenter also stated that subcategory
delisting should occur before the compliance date so that facilities do
not put off compliance in the hope or anticipation of delisting.
The second commenter stated that EPA requested comment on the
establishment of PCWP subcategories ostensibly based on physical and
operational characteristics, but in reality based on risk. According to
the commenter, this indirect approach is just a variation on the
approach (direct reliance on risk) that it claims EPA itself notes
would disrupt and weaken establishment of MACT floors, and is
accordingly unlawful. The commenter stated that, even if these
approaches were lawful, to the extent that EPA's proposal could be read
to suggest that facilities could be allowed to become part of the
allegedly low-risk subcategory in the future without additional EPA
rulemaking, this too would be unlawful. According to the commenter, CAA
section 112(c)(9) provides the EPA Administrator alone the authority to
make delisting determinations, and such authority may not be delegated
to other government authorities or private parties. The commenter
stated that EPA's proposal suggests an approach entirely backward from
the statute-allowing sources to demonstrate after-the-fact that they
belong in a subcategory that has been delisted under section 112(c)(9),
when the statute requires that EPA determine that no source in the
category emits cancer-causing HAP above specified levels, or that no
source in the category or subcategory emit non-carcinogenic HAP above
specified levels, by the time EPA establishes the standard. The
commenter stated that EPA has provided no explanation of how the
suggested approaches would be lawful or workable.
The third commenter indicated that low risk is an adequate and
appropriate criterion for categorization. The commenter disagreed that
EPA should create and delist categories on a technology basis when the
intent is delisting of low-risk facilities. The commenter believed that
seeking a technology-based surrogate for risk is unnecessary within the
statutory framework. The commenter noted that the Congressional intent
was ``to avoid regulatory costs which would be without public health
benefit.'' (S. Rep. No. 228, 101st Cong., 1st. Sess. 175-6 (1990))
Nevertheless, the commenter described some technology-based criteria
that they believed could be used to develop low-risk groups of PCWP
facilities.
Four commenters addressed the impact that creation of a low-risk
subcategory under CAA section 112(c)(9) could have on the establishment
of MACT floors for the PCWP category. Two commenters argued that such
subcategorization would have a negative effect. One commenter stated
that this situation provided a valid reason for EPA not to mix risk-
based and technology-based standards development. The commenter added
that EPA also did not address how the ``once in, always in'' policy
would apply in such a situation. The other commenter stated that this
situation was another compelling reason why the suggested section
112(c)(9) subcategorization approach was unlawful and arbitrary. The
commenter stated that the flaw was so obvious, inherent, and contrary
to the MACT floor provisions of CAA section 112 and its legislative
history, that it proves the undoing of the suggested section 112(c)(9)
exemption. According to the commenter, EPA cannot simultaneously
exercise its source category delisting authority consistent with
section 112(c)(9), establish appropriate MACT floors under CAA section
112(d), and establish subcategory exemptions in the manner suggested by
EPA, because the latter approach contravenes both section 112(c)(9) and
the section 112(d) floor-setting process. The commenter stated that CAA
section 112's major source thresholds and statutory deadlines make
clear that sources meeting MACT by the time EPA is required to issue
MACT standards must install MACT controls and may not subsequently
throw them off or be relieved from meeting the MACT-level standards.
While the CAA section 112(f) residual risk process allows EPA to
establish more stringent emissions standards, there is nothing in the
CAA that suggests EPA possesses authority to relax promulgated MACT
standards.
The third commenter indicated that dilution of the MACT floor would
not occur if low-risk category delisting occurred as follows: (1)
Propose low-risk category with final PCWP rule, (2) promulgate low-risk
category 6 months after proposal, and (3) delist facilities prior to
MACT compliance deadline. If EPA issued the final PCWP rule-thereby
setting the MACT floor-before it allowed affected sources to apply for
inclusion in the low-risk category to be delisted, then every affected
source would be considered in the establishment of the MACT floor.
Thus, as a result of this timing, the MACT floor could not be diluted
because no sources would be exempted from MACT before the MACT floor is
set.
The fourth commenter believed that a MACT floor reevaluation would
be appropriate and would further ensure that only facilities posing
significant risk are required to install expensive controls.
Response: We feel that establishing a low-risk PCWP subcategory
under CAA section 112(c)(1) and deleting that subcategory under CAA
section 112(c)(9) best balances Congress' dual
[[Page 45989]]
concerns that categories and subcategories of major sources of HAP be
subject to technology-based (and possible future risk-based) emission
standards, but that undue burdens not be placed on groups of sources
within the PCWP source category whose HAP emissions are demonstrated to
present little risk to public health and the environment. We do not
contend that the CAA specifically directs us to establish categories
and subcategories of HAP sources based on risk, and we recognize that,
at the time of the 1990 CAA Amendments, Congress may have assumed that
we would generally base categories and subcategories on the traditional
technological, process, output, and product factors that had been
considered under CAA section 111. However, when properly considered, it
becomes apparent that Congress did not intend the unduly restrictive-
and consequently over-regulatory-reading of the CAA that some
commenters urge regarding low-risk PCWP facilities.
Numerous CAA section 112 provisions evidence Congress' intent that
we be able to find that sources, such as those in the PCWP category
whose HAP emissions are below identified risk levels, should not
necessarily be subject to MACT. These provisions, together with other
indications of Congressional intent regarding the goals of section 112,
must all be considered in determining whether we may base a PCWP
subcategory on risk and delist that group of sources, without requiring
additional HAP regulation that would be redundant for purposes of
meeting Congress' risk-based goals.
While it is true that CAA section 112(c)(1) provides that ``[t]o
the extent practicable, the categories and subcategories listed under
this subsection shall be consistent with the list of source categories
established pursuant to section 111 and part C[,]'' the provision also
states that ``[n]othing in the preceding sentence limits the
Administrator's authority to establish subcategories under this
section, as appropriate.'' Therefore, by its plain terms, section
112(c)(1) does not preclude basing subcategories on criteria other than
those traditionally used under section 111 before 1990, or those used
after 1990 for sections 111 and 112. Moreover, while after 1990 we have
principally used the traditional criteria to define categories and
subcategories, such use in general does not restrict how we may define
a subcategory in a specific case, ``as appropriate,'' since each HAP-
emitting industry presents its own unique situation and factors to be
considered. (See, e.g., Sierra Club v. EPA, D.C. Cir. No. 02-1253, 2004
U.S. App. LEXIS 348 (decided Jan. 13, 2004).)
Even assuming for argument that the language of section 112(c)(1)
may initially appear to restrict our authority to define subcategories,
section 112(c)(1) cannot be read in isolation. A broad review of the
entire text, structure, and purpose of the statute, as well as
Congressional intent shows that, applied within the context of CAA
section 112(c)(9), our approach of defining a low-risk subcategory of
PCWP affected sources is reasonable, at the very least as a way to
reconcile the possible tension between the arguably restrictive
language of section 112(c)(1) and the Congressional intent behind
section 112(c)(9). (See, e.g., Virginia v. Browner, 80 F.3d 869, 879
(4th Cir. 1996).) Alternatively, even if the language is clear on its
face in restricting our ability to define subcategories, we feel that,
as a matter of historical fact, Congress could not have meant what the
commenter asserts it appears to have said, and that as a matter of
logic and statutory structure, it almost surely could not have meant
it. (See, e.g., Engine Mfrs. Ass'n v. EPA, 88 F.3d 1075, 1089 (D.C.
Cir. 1996).)
Our interpretation of the CAA is a reasonable accommodation of the
statutory language and Congressional intent regarding the relationship
of the statutory categorization and subcategorization, delisting, MACT
and residual risk provisions that apply to the PCWP category. This
becomes clear in light of the issue addressed by commenters, which is
whether we may delist a subcategory of low-risk PCWP affected sources
only if such a group of sources is defined by criteria we have
traditionally used to define categories and subcategories for
regulatory, rather than delisting purposes. Our approach implements
Congressional intent to avoid the over-regulatory result that flows
from an overly rigid reading of the CAA. When the CAA is read as a
whole, it is apparent that Congress-which in 1990 likely did not fully
anticipate the policy considerations that come into play in regulating
HAP emissions from PCWP affected sources-has not spoken clearly on the
precise issue. Our interpretation is necessary to fill this statutory
gap and prevent the thwarting of Congressional intent not to
unnecessarily burden low-risk PCWP facilities by forcing them to meet
stringent MACT controls when they already meet the risk-based goals of
section 112. Our interpretation thus lends symmetry and coherence to
the statutory scheme.
While we do not feel that CAA section 112(c)(1) actually restricts
our authority to establish a low-risk PCWP subcategory, even if the
language is so restrictive, it must be read within the context of
Congress' purpose in allowing us to delist categories and subcategories
of low-risk sources that are defined according to the traditional
criteria under CAA section 111. It is beyond dispute that Congress
determined that certain identifiable groups or sets of sources may be
delisted if, as a group and without a single constituent source's
exception, they are below the enumerated eligibility criteria of CAA
section 112(c)(9). There is no apparent reason why such a group or set
of sources must be limited to those defined by traditional
categorization or subcategorization criteria. This is because, first,
Congress in section 112(c)(1) clearly did not absolutely prohibit us
from basing categories and subcategories on other criteria generally;
and, second, the underlying characteristic of an eligible set or group
of sources under section 112(c)(9)-that no source in the set or group
presents risks above the enumerated levels-can be applied under several
approaches to defining categories and subcategories and is not
dependent upon such set or group being traditionally defined in order
to implement the purpose of section 112(c)(9). Put another way, there
is nothing apparent in the statute that precludes us from delisting a
discernible set of low-risk PCWP affected sources just because that set
cannot also be defined according to other traditional criteria that
have nothing to do with the question of whether each of the constituent
PCWP affected sources is low risk. As a matter of logic and statutory
structure, Congress almost surely could not have meant to require that
every identifiable group of low-risk PCWP affected sources, no matter
how large in number or in percentage with respect to higher-risk
affected sources in the PCWP category, must remain subject to CAA
section 112, simply because that group could not be subcategorized as
separate from the higher risk PCWP affected sources by application of
traditional subcategorization criteria.
Where Congress squarely confronted the issue, it explicitly
provided relief for categories and subcategories, defined by
traditional criteria, that also happen to present little risk. (See CAA
sections 112(d)(4), 112(c)(9), and 112(f)(2).) These CAA provisions
addressing risk-based relief from, or thresholds for, HAP emissions
regulation evidence
[[Page 45990]]
Congressional concern that the effects of such pollution be taken into
account, where appropriate, in determining whether regulation under CAA
section 112 is necessary. At the time of the 1990 Amendments, Congress
did not consider it necessary to provide express relief for additional
groups such as low-risk PCWP facilities, beyond those defined by
traditional category and subcategory criteria, because it assumed we
could implement a comprehensive regulatory scheme for air toxics that
would both address situations where technology-based standards were
needed to reduce source HAP emissions to levels closer to the risk-
based goals of section 112, and avoid unnecessary imposition of
technology-based requirements on groups of sources that were already
meeting those goals. Congress enacted or revised various CAA air toxics
provisions--including sections 112(c), (d) and (f)--to that end. Had
events unfolded in that anticipated fashion, in the case of each
industrial category and subcategory, there would have been a perfect
correlation between the traditional criteria for defining categories
and subcategories and the facts showing whether those groups are either
high-or low-risk HAP sources.
This context turned out to be more complex than Congress
anticipated, and in the case of PCWP facilities there is no clear
differentiation between high-versus low-risk sources that corresponds
to our traditional approach for identifying source categories and
subcategories. Nevertheless, as in the case of a low-risk source group
defined by traditional category or subcategory criteria, for the PCWP
industry, we are able to identify a significant group of sources whose
HAP emissions pose little risk to public health and the environment,
applying the same section 112(c)(9) delisting criteria that would apply
to any traditionally-defined source group. We feel it is reasonable to
conclude that Congress would not have intended to over-regulate the
low-risk PCWP affected sources due to the inability to define such a
group by traditional criteria and thereby frustrate the coherent scheme
Congress set forth of ensuring that HAP sources ultimately meet common
risk-based goals under section 112.
The commenter's assertion that we are inappropriately altering our
interpretation of the applicable statutory provisions and departing
from the traditional categorization and subcategorization criteria in
addressing low-risk PCWP facilities is thus unfounded. As explained
above, the complexity of the air toxics problem and the relationship
between the traditional criteria and what might be groups of low-risk
sources, a context not fully understood by either Congress or EPA at
the time of the 1990 Amendments, provides adequate justification for
any unique applications of the our approach for low-risk PCWP facilities.
Our approach does not equate to one that Congress considered and
rejected that would have allowed source-by-source exemptions from MACT
based on individualized demonstrations that such sources are low risk.
This is because, contrary to that approach, we rely upon the
application of specific eligibility criteria that are defined in
advance of any source's application to be included in the low-risk PCWP
subcategory, in much the same way as any other applicability
determination process works. Moreover, in response to the assertion
that our approach nevertheless conflicts with legislative history
rejecting a similar (but not identical) approach Congress considered
under CAA section 112, this legislative history is not substantive
legislative history demonstrating that Congress voted against relief
from MACT in this situation-there is no such history. The commenters
point to a provision in the House bill that was not enacted but that
would have provided in certain situations for case-by-case exemptions
for low-risk sources. There is no evidence that this provision was ever
debated, considered, or voted upon, so its not being enacted is not
probative of congressional intent concerning our ability to identify
and delist a group of low-risk PCWP affected sources. Instead, it is
reasonable to assume that, had Congress been aware in 1990 of the
possibility that an identifiable group of PCWP affected sources is low
risk, while that group does not correspond to traditional criteria
differentiating categories and subcategories, Congress would have
expressly, rather than implicitly, authorized our action here.
Moreover, the commenters are unable to cite any provision in CAA
section 112 that would prevent us from being able to add individual or
additional groups of low-risk PCWP affected sources to the group we
initially identify in our final delisting action, as those additional
low-risk PCWP affected sources prove their eligibility for inclusion in
the delisted group over time. In fact, the approach we are taking for
identifying additional low-risk PCWP affected sources is fully
consistent with the approach we have long taken in identifying, on a
case-by-case basis and subject to appropriate review, whether
individual sources are members of a category or subcategory subject to
standards adopted under CAA sections 111 and 112.
Regarding the comment that Congress did not expressly provide
relief for carcinogen-emitting low-risk groups of sources within the
PCWP category other than as an entire category, we construe the
provisions of CAA section 112(c)(9) to apply to listed subcategories as
well as to categories. This construction is logical in the context of
the general regulatory scheme established by the statute, and it is the
most reasonable one because section 112(c)(9)(B)(ii) expressly refers
to subcategories. Under a literal reading of section 112(c)(9)(B), no
subcategory could ever be delisted, notwithstanding the explicit
reference to subcategories, since the introductory language of section
112(c)(9)(B) provides explicit authority to only delist categories.
Such a reading makes no sense, at the very least because Congress
plainly assumed we might also delist another collection of sources
besides either categories or subcategories, even in the case of sources
of carcinogens. Both sections 112(c)(9)(B)(i) and (ii) refer
additionally to groups of sources in the case of area sources as being
eligible for delisting, even though only a category of sources is
specifically identified as eligible for delisting in the introductory
language of section 112(c)(9)(B). In light of the broader congressional
purpose behind the delisting authority, we interpret the absence of
explicit references to subcategories in this introductory language and
in section 112(c)(9)(B)(i) as representing nothing more than a drafting
error.
Regarding the comments about establishing PCWP subcategories based
on characteristics other than risk, the criteria for the low-risk
subcategory we are delisting are based solely on risk and not on
technological differences in equipment or emissions. We performed an
analysis to determine which major source PCWP affected sources may be
low-risk affected sources. Whether affected sources are low risk or not
depends on the affected source HAP emissions; and affected source HAP
emissions are a function of the type and amount of product(s) produced,
the type of process units (e.g., direct-fired versus indirect-fired
dryers) used to produce the product, and the emission control systems
in place. Our analysis indicates that the affected sources which show
low risk could include affected sources producing various products such
as particleboard, molded particleboard, medium density fiberboard,
softwood plywood, softwood veneer, fiberboard, engineered wood
products, hardboard, and oriented strandboard. However, there are also
major sources that
[[Page 45991]]
produce these products that are not low risk, and, therefore, product
type cannot be used to define the low-risk subcategory. There is no
correlation between production rate and low-risk affected sources
(e.g., when affected sources are sorted by production rate for their
product, the low-risk affected sources are not always at the lower end
of the production rate range), so production rate cannot be used as
criteria for defining the low-risk subcategory. The low-risk affected
sources use a variety of process equipment (e.g., veneer dryers at
softwood plywood plants and tube dryer at MDF plants). This same
equipment is used at PCWP plants that are not low risk, and, therefore,
there is no process unit type distinction that can be used to define
the low-risk subcategory. The pollutant that drives the risk estimate
can vary from affected source to affected source because of the
different types of process units at each affected source. There is no
clear distinction among low-risk and non-low-risk affected sources when
ranked by emissions of individual pollutants because of other factors
that contribute to affected source risk such as presence of a co-
located PCWP facility or variability in the pollutants emitted. Thus,
there is no emissions distinction that can be used to define the low-
risk subcategory. There is no technological basis for creating a
subcategory of PCWP affected sources that are low risk. The commonality
between all of the low-risk PCWP affected sources is that they are low
risk, and, therefore, we have established the low-risk subcategory
based on risk.
We do not agree with the commenters' assertions that our approach
for the low-risk PCWP subcategory undermines our ability to identify
the MACT floor for the larger PCWP category, either in today's final
PCWP rule or in any future consideration of technological development
under CAA section 112(d)(6). This is because, while low-risk PCWP
affected sources will literally be part of a separate subcategory,
there is nothing in the CAA that prevents us from including them in any
consideration of what represents the best controlled similar source in
the new source MACT floor context, and because it is not unprecedented
for us to look outside the relevant category or subcategory in
identifying the average emission limitation achieved by the best
controlled existing sources if doing so enables us to best estimate
what the relevant existing sources have achieved. In fact, EPA has
taken this very approach in the Industrial Boilers MACT rulemaking, in
order to identify the MACT floor for mercury emissions. Moreover, the
unique issues presented by the low-risk PCWP subcategory show that it
would be unreasonable to exclude any better-performing low-risk PCWP
sources from the MACT floor pool for the larger PCWP category.
Traditionally, EPA has based categories and subcategories partly on
determinations of what pollution control measures can be applied to the
relevant groups of sources in order to effectively and achievably
reduce HAP. In other words, EPA has identified subcategories for
purposes of identifying the MACT floor in a way that accounts for the
differences of sources types in their abilities to control HAP
emissions. But whether a PCWP source is a low-risk source does not
necessarily turn on such a distinction--two sources might have
identical abilities to control HAP emissions, but the unique
circumstances of one source regarding the impacts of its HAP emissions
will determine whether or not it is a low-risk PCWP source. (In fact,
it is theoretically possible that between two sources the better
performing source will be a high-risk source, and the worse-performing
source will be a low-risk source, based on circumstances that are
unrelated to the question of what abilities the sources have to control
HAP emissions through application of MACT, such as the sources'
locations vis a vis exposed human populations.) Therefore, EPA feels
that not only is it appropriate to include any better-performing low
risk PCWP sources in the MACT floor determinations for the larger PCWP
category, but that excluding such sources simply based on the unique
facts of the impacts of their emissions, with there being no difference
in the abilities of high-risk and low-risk sources to apply HAP
emission control measures, could result in an undesirable weakening of
the MACT floor for the larger PCWP category. To that end, the MACT
floors established for PCWP process units today are in no way affected
by our establishment of the low-risk PCWP subcategory.
Finally, we disagree with the argument by one commenter that the
low-risk PCWP subcategory approach represents an impermissible cost-
based exemption from MACT or factor in determining MACT. Certainly it
is true that costs may not be considered in setting the MACT floor.
However, there is nothing in the CAA that prevents us from noting the
cost impacts, beneficial or adverse, of our actions in setting MACT
floors, assessing possible beyond-the-floor measures, or conducting
risk-based actions under CAA section 112. In fact, we routinely
evaluate the costs of our regulatory actions, even when cost factors
may not be used to influence the regulatory decision itself, in order
to comply with applicable Executive Order and statutory administrative
review requirements. Simply because there is a cost benefit to some
members of the PCWP category in our establishing a low-risk PCWP
subcategory does not make that action impermissible, provided that our
subcategorization and delisting are otherwise properly based on the
appropriate risk-based criteria under CAA section 112(c)(9). Section
112 by its own terms does not forbid the goal of achieving
environmental protection in a less costly manner. Similarly, it is
appropriate for EPA to note the beneficial air pollution-related
impacts of not requiring low-risk PCWP sources to, for example, install
criteria pollutant emission-producing RTOs. While it is true that such
air quality-related impacts could not constitute non-air quality health
and environmental impacts that EPA must consider when setting MACT
under CAA section 112(d)(2), nothing in the CAA prevents EPA from
taking account of such impacts in developing its policy regarding
whether it is appropriate to delist a subcategory under section
112(c)(9) when that subcategory otherwise meets the statutory criteria
for delisting. Therefore, EPA does not agree with commenters who claim
that its approach to delisting the low risk PCWP subcategory conflicts
with how it has argued issues regarding either de minimis authority,
cost-based exemptions from MACT, or the treatment of non-air quality
impacts and the consideration of risk in setting the actual MACT
standard before the U.S. Court of Appeals for the D.C. Circuit. Nor
does our approach contravene any of that Court's rulings on these issues.
3. Criteria for Demonstrating Low Risk Dose-response Values
Comment: Two commenters suggested that EPA incorporate into the
PCWP rule the findings of the nationwide wood products risk assessment,
which they claim demonstrates that the vast majority of wood products
sources cause no meaningful risk to human health or the environment at
current emission levels. The commenters stated that the risk assessment
used existing air dispersion modeling studies of 34 wood products
facilities throughout the U.S. to estimate the maximum annual off-site
HAP concentrations at wood products facilities nationwide. According to
the commenters, the risk assessment indicates that large
[[Page 45992]]
subgroups of facilities that are affected sources under the PCWP rule
as proposed (i.e., fiberboard, medium density fiberboard, and plywood
facilities) generally are expected to pose insignificant risks to human
health, based on a comparison of predicted off-site concentrations with
applicable health benchmarks. One of the commenters stated that many of
the facilities with low off-site concentrations will likely be smaller
plants that would not be able to justify installation of (additional)
emission controls and may face closure without a risk-based compliance
option. The other commenter stated that a comparison of off-site
concentrations of formaldehyde and acetaldehyde with benchmarks
reflecting the latest toxicological evidence indicates that exposures
to those HAP are well below levels of concern. Acrolein was the only
HAP with potential exposures at some affected sources (i.e., subset of
fiberboard, medium density fiberboard and plywood affected sources)
that exceeded the health benchmark. However, the commenter stated that
the acrolein findings may not represent an actual risk to human health
because exceedences of the benchmark may be attributable to EPA
averaging a large number of non-detects at one-half the detection
limit, thereby artificially increasing predicted acrolein emissions.
Based on these overall findings, the commenter concluded that the wood
products risk assessment indicates that incinerator control is not
warranted on the basis of human health concerns for a large number of
facilities.
Response: We acknowledge receipt of the industry-sponsored
nationwide wood products MACT risk assessment submitted by the
commenter. However, we conducted our own risk analysis to evaluate the
merits of including and delisting a low-risk subcategory in today's
final PCWP rule. The methodology used in our risk analysis differed
widely from the methodology used in industry's risk assessment. For
example, industry's risk assessment was based on previously conducted
air dispersion modeling studies for 34 PCWP facilities, while our
analysis used emission estimates developed for each PCWP affected
source expected to be a major source of HAP. We used different
(generally more protective) human health benchmarks in our risk
assessment than were used in industry's risk assessment. We also
considered all HAP (including metal HAP) in our risk analysis, whereas
industry's risk assessment considered only methanol, formaldehyde,
acetaldehyde, acrolein, phenol, and propionaldehyde.
Based on our risk analysis, we conclude that HAP emissions from
some PCWP affected sources pose little risk to human health and the
environment. Therefore, we have included a subcategory of low-risk PCWP
affected sources in today's final PCWP rule, and are delisting that
subcategory. Appendix B to subpart DDDD of 40 CFR part 63 includes
procedures that facilities may use to demonstrate that they are part of
the delisted low-risk subcategory, and, therefore, are not subject to
the compliance options included in today's final PCWP MACT rule. To
demonstrate eligibility for the low-risk subcategory, facilities must
first conduct emissions testing for up to 13 HAP (five organic HAP from
all process units, seven metal HAP from direct-fired process units, and
MDI from presses processing product containing MDI resin). The
rationale for selection of these 13 HAP is described elsewhere in this
section and in the supporting documentation for the final rule.
Facilities must use the results from emissions testing to preliminarily
demonstrate, subject to EPA approval, that they are part of the low-
risk subcategory using either a look-up table analysis (based on the
look-up tables included in appendix B to subpart DDDD of 40 CFR part
63) or site-specific risk assessment methodology (described in appendix
B to subpart DDDD of 40 CFR part 63 and other analytical tools, such as
the ``Air Toxics Risk Assessment Reference Library'' if appropriate for
the specific source) and risk benchmarks (described in appendix B to
subpart DDDD of 40 CFR part 63).
Regarding acrolein, the commenter is correct in that, when
developing AP-42 emission factors, we used a value of one-half the
detection limit for all non-detect sample runs if acrolein was detected
in any sample runs from the applicable source category. Acrolein has
been detected in process unit emissions from all sectors of the PCWP
industry, except for hardwood plywood manufacturing. When using
emission factors to estimate emissions from PCWP facilities, we did not
estimate emissions of a pollutant when all of the emissions test runs
were non-detect. However, we did use emission factors that included a
mixture of detectable values and values based on one-half of the method
detection limit (MDL) when acrolein was detected at least once for a
particular type of process unit. We maintain that this approach to
handling non-detects is appropriate for the purposes that we used the
emissions data. Facilities will conduct emissions tests instead of
using emission factors to demonstrate eligibility for the low-risk
subcategory. To prevent facilities from including HAP that are not
detected in their low-risk demonstrations, appendix B to subpart DDDD
of 40 CFR part 63 states that facilities may use zero for non-detects
when all of the emission test runs are below the MDL, provided that
certain criteria are met to ensure that emissions testing and analysis
procedures are adequate to detect low concentrations of HAP.
Comment: One commenter stated that CAA section 112(d)(4) is
particularly ill-suited to the PCWP and industrial boiler source
categories. The commenter stated that, even if EPA had authority to
create individualized MACT exemptions based on health thresholds, it
could not do so if there is insufficient evidence on the pollutants
emitted to establish a NOEL. According to the commenter, section
112(d)(4) does not apply for chemicals that do not have a well-defined
threshold based on reliable science. The commenter stated that
available evidence does not establish a no-effect threshold for
acetaldehyde, acrolein, benzene, carbon tetrachloride, chloroform,
formaldehyde, manganese, methylene chloride, and phenol. As rationale,
the commenter presented a summary of the available health effects data
for each of these pollutants.
Response: As stated elsewhere in this preamble, we are not pursuing
establishment of a threshold emission rate for the PCWP source category
under CAA section 112(d)(4) because PCWP affected sources emit non-
threshold pollutants. Therefore, this comment is irrelevant in the
context of the PCWP rule. Comments pertaining to the Industrial/
Commercial/Institutional Boilers and Process Heaters NESHAP are
addressed in the comment-response document for that rule. (See Docket
ID No. OAR-2002-0058.)
Comment: Two commenters expressed concern about the health
benchmark data sources that EPA used. The first commenter argued that
the proposal inappropriately used draft guidelines and toxicity
profiles that had not been subject to public review and/or were not
publicly available. The commenter was particularly concerned with the
use of non-linear carcinogenic risk values and toxicity profiles (for
HAP) that have not been finalized and are not available for review by
the public.
The second commenter argued that EPA should not rely solely on the
health benchmarks in its Integrated Risk Information System (IRIS)
database. The commenter stated that IRIS, while useful for obtaining
information about the health effects of chemicals, is far
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