Disclaimer: These guidelines were developed under contract using generally accepted secondary sources. The protocol used by the contractor for surveying these data sources was developed by the National Institute for Occupational Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA), and the Department of Energy (DOE). The information contained in these guidelines is intended for reference purposes only. None of the agencies have conducted a comprehensive check of the information and data contained in these sources. It provides a summary of information about chemicals that workers may be exposed to in their workplaces. The secondary sources used for supplements 111 and 1V were published before 1992 and 1993, respectively, and for the remainder of the guidelines the secondary sources used were published before September 1996. This information may be superseded by new developments in the field of industrial hygiene. Therefore readers are advised to determine whether new information is available.

OCCUPATIONAL SAFETY AND HEALTH GUIDELINE FOR CHLORODIPHENYL (54% CHLORINE)

INTRODUCTION

This guideline summarizes pertinent information about chlorodiphenyl (54% chlorine) for workers and employers as well as for physicians, industrial hygienists, and other occupational safety and health professionals who may need such information to conduct effective occupational safety and health programs. Recommendations may be superseded by new developments in these fields; readers are therefore advised to regard these recommendations as general guidelines and to determine whether new information is available.

SUBSTANCE IDENTIFICATION

* Formula

C(12)H(5)Cl(5) (approximately)

* Structure

(For Structure, see paper copy)

* Synonyms

Polychlorinated biphenyl, PCB, chlorinated diphenyl, polychlorinated polyphenyl, arochlor 1254, aroclor 1254, askarel

* Identifiers

1. CAS No.: 11097-69-1

2. RTECS No.: TQ1360000

3. DOT UN: 2315 31

4. DOT label: Class 9 (miscellaneous hazardous material)

* Appearance and odor

Chlorodiphenyl (54% chlorine) is a pale yellow, viscous liquid with a mild hydrocarbon odor. Production and sale of chlorodiphenyls was halted in 1977, but these substances are still found in transformers and capacitors.

CHEMICAL AND PHYSICAL PROPERTIES

* Physical data

1. Molecular weight: 326 (approximately)

2. Boiling point (at 760 mm Hg): 365-390 degrees C (689-734 degrees F)

3. Specific gravity: Data not available.

4. Vapor density: Data not available.

5. Melting/Freezing point: Data not available.

6. Vapor pressure at 20 degrees C (68 degrees F): Data not available.

7. Solubility: Insoluble in water; soluble in most organic solvents.

8. Evaporation rate: Data not available.

* Reactivity

1. Conditions contributing to instability: Exposure to fire conditions may cause the formation of a black soot containing polychlorinated dibenzofurans and chlorinated benzo-p-dioxins.

2. Incompatibilities: Contact between chlorodiphenyl (54% chlorine) and strong oxidizing agents may cause fires and explosions.

3. Hazardous decomposition products: Toxic gases and vapors such as hydrogen chloride, chlorinated dibenzofurans, chlorinated phenols, chlorinated naphthalenes, and carbon monoxide may be released in a fire involving chlorodiphenyl (54% chlorine).

4. Special precautions: None reported.

* Flammability

The National Fire Protection Association has not assigned a flammability rating to chlorodiphenyl (42% chlorine). Other sources list the PCBs as combustible materials.

1. Flash point: Data not available.

2. Autoignition temperature: Data not available.

3. Flammable limits in air: Data not available.

4. Extinguishant: For small fires use dry chemical, carbon dioxide, water spray, or regular foam. Use water spray, fog, or regular foam to fight large fires involving chlorodiphenyl (54% chlorine).

Fires involving chlorodiphenyl (54% chlorine) should be fought upwind from the maximum distance possible. Keep unnecessary people away; isolate the hazard area and deny entry. Containers of chlorodiphenyl (54% chlorine) should be moved from the fire area if it is possible to do so safely. Do not scatter spilled materials with high-pressure water streams. Dike fire control water for later disposal. Firefighters should wear a full set of protective clothing and self-contained breathing apparatus when fighting fires involving chlorodiphenyl (54% chlorine).

EXPOSURE LIMITS

* OSHA PEL

The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for chlorodiphenyl (54% chlorine) is 0.5 milligram per cubic meter (mg/m(3)) of air as an 8-hour time-weighted average (TWA) concentration. The OSHA PEL also bears a "Skin" notation, which indicates that the cutaneous route of exposure (including mucous membranes and eyes) contributes to overall exposure [29 CFR 1910.1000, Table Z-].

* NIOSH REL

The National Institute for Occupational Safety and Health (NIOSH) has established a recommended exposure limit (REL) for chlorodiphenyl (54% chlorine) of 0.001 mg/m(3) as a TWA for up to a 10-hour workday and a 40-hour workweek. NIOSH considers chlorodiphenyl (54% chlorine) a potential occupational carcinogen [NIOSH 1992].

* ACGIH TLV

The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned chlorodiphenyl (54% chlorine) a threshold limit value (TLV) of 0.5 mg/m(3) as a TWA for a normal 8-hour workday and a 40-hour workweek. The ACGIH also assigns a "Skin" notation to chlorodiphenyl (54% chlorine)] [ACGIH 1994, p. 16].

* Rationale for Limits

The NIOSH limit is based on the risk of skin, liver, and reproductive effects, and on the potential for cancer; also on based on tumors of the liver and pituitary gland and leukemias noted in animals [NIOSH 1992].

The ACGIH limit is based on the risk of systemic toxicity [ACGIH 1991, p. 286].

HEALTH HAZARD INFORMATION

* Routes of Exposure

Exposure to chlorodiphenyl (54% chlorine) can occur through inhalation, ingestion, eye or skin contact, and absorption through the skin [Sittig 1991].

* Summary of toxicology

1. Effects on Animals: Chlorodiphenyl (54% chlorine) is a carcinogen in animals; it causes liver and bladder tumors. Chlorodiphenyl (54% chlorine) is also a liver and reproductive toxin. Chlorodiphenyl is poorly metabolized and tends to accumulate in lipid-rich tissues, such as brain tissue. The more highly chlorinated PCBs, such as 54 percent chlorodiphenyl, have greater carcinogenic potential than the less chlorinated chlorodiphenyls [Hathaway et al. 1991]. This substance is toxic to the liver, causing fatty degeneration, cell death, hypertrophy, and induction of microsomal enzymes [Hathaway et al. 1991]. The oral LD(50) in rats is 1010 mg/kg, and the intravenous LD(50) in the same species is 358 mg/kg [NIOSH 1995]. The minimum lethal dermal dose in rabbits is 1.5 g/kg [Hathaway et al. 1991]. Repeated dosing with chlorodiphenyl (54% chlorine) caused bladder tumors in rats [Gosselin 1984]. Dietary administration of 54% chlorine chlorodiphenyl to mice and rats has caused a significant excess of benign and malignant liver tumors in several bioassays. Rats also developed interstitial metaplasia and a low, statistically nonsignificant incidence of stomach adenocarcinomas [IARC 1987]. The International Agency for Research on Cancer has concluded that there is sufficient evidence of the carcinogenic risk of chlorodiphenyl (54% chlorine) in animals [IARC 1987]. Chlorodiphenyl (54% chlorine) is mutagenic in mammalian test systems [NIOSH 1995].

2. Effects on Humans: Exposure to chlorodiphenyl (54% chlorine) causes chloracne, eye and mucous membrane irritation, and liver damage. It may also be a potential occupational carcinogen. Workers exposed to chlorodiphenyl (54% chlorine) in electrical capacitor filling and sealing operations have shown a slight increase in the incidence of cancer, particularly melanomas of the skin; another study showed an excess number of deaths due to cancer of the liver and biliary passages in chlorodiphenyl-exposed workers [IARC 1987]. A study of workers in Italy who had been exposed to a mixture of chlorodiphenyl (54% and 42% chlorine) showed a significant increase in cancer mortality; male workers had a significant excess of gastrointestinal tract tumors (including a liver tumor) and female workers had a significant increase in death from hematological tumors [IARC 1987]. The International Agency for Research on Cancer (IARC) has concluded that the available studies suggest an association between cancer and exposure to PCBs. IARC notes that the increased risk from hepatobiliary cancer was consistent across different studies [IARC 1987]. Workers exposed to concentrations below 1 mg/m(3) for several months developed eczema, skin burning and systemic effects [Parmeggiani 1983]. Studies of occupationally exposed persons have shown evidence of liver injury when tested by serum enzyme studies or other liver function tests; deaths due to toxic hepatitis have also been reported [Gosselin 1984].

* Signs and symptoms of exposure

1. Acute exposure: Exposure to chlorodiphenyl (54% chlorine) cause irritation and burning of the eyes and irritation of the nose, throat, and skin. It may also cause headache, jaundice, vomiting, nausea, edema of the facial skin, depression, dizziness, and abdominal pain.

2. Chronic exposure: Chronic exposure to chlorodiphenyl (54% chlorine) causes chloracne, eczema, liver dysfunction, and peripheral neuropathies. Exposure may also cause cancer (especially melanoma), gastrointestinal tract tumors, and hematopoietic tumors.

EMERGENCY MEDICAL PROCEDURES

* Emergency medical procedures: [NIOSH to supply]

5. Rescue: Remove an incapacitated worker from further exposure and implement appropriate emergency procedures (e.g., those listed on the Material Safety Data Sheet required by OSHA's Hazard Communication Standard [29 CFR 1910.1200]). All workers should be familiar with emergency procedures, the location and proper use of emergency equipment, and methods of protecting themselves during rescue operations.

EXPOSURE SOURCES AND CONTROL METHODS

The following operations may involve chlorodiphenyl (54% chlorine) and lead to worker exposures to this substance:

* Used in transformers

* Used in heat transfer systems and hydraulic systems

* Used in and liberated during servicing of electromagnets, switches, voltage regulators, capacitors, circuit breakers, reclosers, and cable

* Used on compressors and in the liquid of natural gas pipelines

* Used as a microscopic mounting medium, as an immersion oil in fluorescence microscopy, and as an optical liquid

* Used in research and development

* Used in carbonless copy paper

Methods that are effective in controlling worker exposures to chlorodiphenyl (54% chlorine), depending on the feasibility of implementation, are as follows:

* Process enclosure
* Local exhaust ventilation
* General dilution ventilation
* Personal protective equipment

Workers responding to a release or potential release of a hazardous substance must be protected as required by paragraph (q) of OSHA's Hazardous Waste Operations and Emergency Response Standard [29 CFR 1910.120].

Good sources of information about control methods are as follows:

1. ACGIH [1992]. Industrial ventilation--a manual of recommended practice. 21st ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

2. Burton DJ [1986]. Industrial ventilation--a self study companion. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

3. Alden JL, Kane JM [1982]. Design of industrial ventilation systems. New York, NY: Industrial Press, Inc.

4. Wadden RA, Scheff PA [1987]. Engineering design for control of workplace hazards. New York, NY: McGraw-Hill.

5. Plog BA [1988]. Fundamentals of industrial hygiene. Chicago, IL: National Safety Council.

MEDICAL SURVEILLANCE

OSHA is currently developing requirements for medical surveillance. When these requirements are promulgated, readers should refer to them for additional information and to determine whether employers whose employees are exposed to chlorodiphenyl (54% chlorine) are required to implement medical surveillance procedures.

* Medical Screening

Workers who may be exposed to chemical hazards should be monitored in a systematic program of medical surveillance that is intended to prevent occupational injury and disease. The program should include education of employers and workers about work-related hazards, early detection of adverse health effects, and referral of workers for diagnosis and treatment. The occurrence of disease or other work-related adverse health effects should prompt immediate evaluation of primary preventive measures (e.g., industrial hygiene monitoring, engineering controls, and personal protective equipment). A medical surveillance program is intended to supplement, not replace, such measures. To detect and control work-related health effects, medical evaluations should be performed (1) before job placement, (2) periodically during the term of employment, and (3) at the time of job transfer or termination.

* Preplacement medical evaluation

Before a worker is placed in a job with a potential for exposure to chlorodiphenyl (54% chlorine), a licensed health care professional should evaluate and document the worker's baseline health status with thorough medical, environmental, and occupational histories, a physical examination, and physiologic and laboratory tests appropriate for the anticipated occupational risks. These should concentrate on the function and integrity of the skin, blood, and liver.

A preplacement medical evaluation is recommended to assess medical conditions that may be aggravated or may result in increased risk when a worker is exposed to chlorodiphenyl (54% chlorine) at or below the prescribed exposure limit. The health care professional should consider the probable frequency, intensity, and duration of exposure as well as the nature and degree of any applicable medical condition. Such conditions (which should not be regarded as absolute contraindications to job placement) include a history and other findings consistent with diseases of the skin, blood, or liver.

* Periodic medical evaluations

Occupational health interviews and physical examinations should be performed at regular intervals during the employment period, as mandated by any applicable Federal, State, or local standard. Where no standard exists and the hazard is minimal, evaluations should be conducted every 3 to 5 years or as frequently as recommended by an experienced occupational health physician. Additional examinations may be necessary if a worker develops symptoms attributable to chlorodiphenyl (54% chlorine) exposure. The interviews, examinations, and medical screening tests should focus on identifying the adverse effects of chlorodiphenyl (54% chlorine) on the skin, blood, or liver. Current health status should be compared with the baseline health status of the individual worker or with expected values for a suitable reference population.

* Termination medical evaluations

The medical, environmental, and occupational history interviews, the physical examination, and selected physiologic or laboratory tests that were conducted at the time of placement should be repeated at the time of job transfer or termination to determine the worker's medical status at the end of his or her employment. Any changes in the worker's health status should be compared with those expected for a suitable reference population.

* Biological monitoring

Biological monitoring involves sampling and analyzing body tissues or fluids to provide an index of exposure to a toxic substance or metabolite. Chlorodiphenyl (54% chlorine) can be detected in the blood, plasma, or adipose tissue of exposed individuals. There is apparently a close correlation between the degree and duration of exposure and the blood concentration of chlorodiphenyl in exposed workers. The upper limit of the normal concentration of chlorodiphenyl in blood is 200 micrograms per liter in occupationally exposed workers. Plasma concentrations also show good correlation with occupational exposure; plasma concentration above 2 to 4 microgram per liter indicate significant exposure.

WORKPLACE MONITORING AND MEASUREMENT

Determination of a worker's exposure to airborne chlorodiphenyl (54% chlorine) is made using an OSHA Versatile Sampler (OVS-2) 13 mm XAD-2 tube (270/140 mg sections, 20/60 mesh) with a glass fiber filter enclosed. Samples are collected at a maximum flow rate of 1.0 liter/minute until a maximum collection volume of 60 liters is reached. Analysis is conducted by gas chromatography using an electron capture detector (GC/ECD). This method is described in the OSHA Computerized Information System [OSHA 1994] and is partially validated. NIOSH has a similar method (Method No. 5503) for the sampling and analysis of polychlorobiphenyls [NIOSH 1994b].

PERSONAL HYGIENE PROCEDURES

If chlorodiphenyl (54% chlorine) contacts the skin, workers should flush the affected areas immediately with plenty of water, followed by washing with soap and water.

Clothing contaminated with chlorodiphenyl (54% chlorine) should be removed immediately, and provisions should be made for the safe removal of the chemical from the clothing. Persons laundering the clothes should be informed of the hazardous properties of chlorodiphenyl (54% chlorine), particularly its potential for causing systemic toxicity through dermal absorption.

A worker who handles chlorodiphenyl (54% chlorine) should thoroughly wash hands, forearms, and face with soap and water before eating, using tobacco products, using toilet facilities, applying cosmetics, or taking medication.

Workers should not eat, drink, use tobacco products, apply cosmetics, or take medication in areas where chlorodiphenyl (54% chlorine) or a solution containing chlorodiphenyl (54% chlorine) is handled, processed, or stored.

STORAGE

Chlorodiphenyl (54% chlorine) should be stored in a cool, dry, well- ventilated area in tightly sealed containers that are labeled in accordance with OSHA's Hazard Communication Standard [29 CFR 1910.1200]. Containers of chlorodiphenyl (54% chlorine) should be protected from physical damage and should be stored separately from strong oxidizing agents.

SPILLS AND LEAKS

In the event of a spill or leak involving chlorodiphenyl (54% chlorine), persons not wearing protective equipment and clothing should be restricted from contaminated areas until cleanup has been completed. The following steps should be undertaken following a spill or leak:

1. Notify safety personnel.

2. Remove all sources of heat and ignition.

3. NUMBERED TEXT =Ventilate potentially explosive atmospheres.

4. Do not touch the spilled material; stop the leak if it is possible to do so without risk.

5. Use non-sparking tools.

6. For small liquid spills, take up with sand or other noncombustible absorbent material and place into closed containers for later disposal.

7. For large liquid spills, build dikes far ahead of the spill to contain the chlorodiphenyl (54% chlorine) for later reclamation or disposal.

SPECIAL REQUIREMENTS

U.S. Environmental Protection Agency (EPA) requirements for emergency planning, reportable quantities of hazardous releases, community right-to-know, and hazardous waste management may change over time. Users are therefore advised to determine periodically whether new information is available.

* Emergency planning requirements

Chlorodiphenyl (54% chlorine) is not subject to EPA emergency planning requirements under the Superfund Amendments and Reauthorization Act (SARA) (Title III) in 42 USC 11022.

* Reportable quantity requirements for hazardous releases

A hazardous substance release is defined by EPA as any spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment (including the abandonment or discarding of contaminated containers) of hazardous substances. In the event of a release that is above the reportable quantity for that chemical, employers are required to notify the proper Federal, State, and local authorities [40 CFR 355.40].

The reportable quantity of chlorodiphenyl (54% chlorine) is 1 pound. If an amount equal to or greater than this quantity is released within a 24-hour period in a manner that will expose persons outside the facility, employers are required to do the following:

- Notify the National Response Center immediately at (800) 424-8802 or at (202) 426-2675 in Washington, D.C. [40 CFR 302.6].

* Community right-to-know requirements

Employers are not required by EPA in 40 CFR Part 372.30 to submit a Toxic Chemical Release Inventory form (Form R) to EPA reporting the amount of chlorodiphenyl (54% chlorine) emitted or released from their facility annually.

* Hazardous waste management requirements

EPA considers a waste to be hazardous if it exhibits any of the following characteristics: ignitability, corrosivity, reactivity, or toxicity as defined in 40 CFR 261.21-261.24. Under the Resource Conservation and Recovery Act (RCRA) [40 USC 6901 et seq.], EPA has specifically listed many chemical wastes as hazardous. Although chlorodiphenyl (54% chlorine) is not specifically listed as a hazardous waste under RCRA, EPA requires employers to treat waste as hazardous if it exhibits any of the characteristics discussed above.

Providing detailed information about the removal and disposal of specific chemicals is beyond the scope of this guideline. The U.S. Department of Transportation, EPA, and State and local regulations should be followed to ensure that removal, transport, and disposal of this substance are conducted in accordance with existing regulations. To be certain that chemical waste disposal meets EPA regulatory requirements, employers should address any questions to the RCRA hotline at (703) 412-9810 (in the Washington, D.C. area) or toll-free at (800) 424-9346 (outside Washington, D.C.). In addition, relevant State and local authorities should be contacted for information on any requirements they may have for the waste removal and disposal of this substance.

RESPIRATORY PROTECTION

* Conditions for respirator use

Good industrial hygiene practice requires that engineering controls be used where feasible to reduce workplace concentrations of hazardous materials to the prescribed exposure limit. However, some situations may require the use of respirators to control exposure. Respirators must be worn if the ambient concentration of chlorodiphenyl (54% chlorine) exceeds prescribed exposure limits. Respirators may be used (1) before engineering controls have been installed, (2) during work operations such as maintenance or repair activities that involve unknown exposures, (3) during operations that require entry into tanks or closed vessels, and (4) during emergencies. Workers should only use respirators that have been approved by NIOSH and the Mine Safety and Health Administration (MSHA).

* Respiratory protection program

Employers should institute a complete respiratory protection program that, at a minimum, complies with the requirements of OSHA's Respiratory Protection Standard [29 CFR 1910.134]. Such a program must include respirator selection, an evaluation of the worker's ability to perform the work while wearing a respirator, the regular training of personnel, respirator fit testing, periodic workplace monitoring, and regular respirator maintenance, inspection, and cleaning. The implementation of an adequate respiratory protection program (including selection of the correct respirator) requires that a knowledgeable person be in charge of the program and that the program be evaluated regularly. For additional information on the selection and use of respirators and on the medical screening of respirator users, consult the latest edition of the NIOSH Respirator Decision Logic [NIOSH 1987b] and the NIOSH Guide to Industrial Respiratory Protection [NIOSH 1987a].

PERSONAL PROTECTIVE EQUIPMENT

Workers should use appropriate personal protective clothing and equipment that must be carefully selected, used, and maintained to be effective in preventing skin contact with chlorodiphenyl (54% chlorine). The selection of the appropriate personal protective equipment (PPE) (e.g., gloves, sleeves, encapsulating suits) should be based on the extent of the worker's potential exposure to chlorodiphenyl (54% chlorine). The resistance of various materials to permeation by chlorodiphenyl (54% chlorine) is shown below:

(*) Not recommended, degradation may occur

To evaluate the use of these PPE materials with chlorodiphenyl (54% chlorine), users should consult the best available performance data and manufacturers' recommendations. Significant differences have been demonstrated in the chemical resistance of generically similar PPE materials (e.g., butyl) produced by different manufacturers. In addition, the chemical resistance of a mixture may be significantly different from that of any of its neat components.

Any chemical-resistant clothing that is used should be periodically evaluated to determine its effectiveness in preventing dermal contact. Safety showers and eye wash stations should be located close to operations that involve chlorodiphenyl (54% chlorine).

Splash-proof chemical safety goggles or face shields (20 to 30 cm long, minimum) should be worn during any operation in which a solvent, caustic, or other toxic substance may be splashed into the eyes.

In addition to the possible need for wearing protective outer apparel (e.g., aprons, encapsulating suits), workers should wear work uniforms, coveralls, or similar full-body coverings that are laundered each day. Employers should provide lockers or other closed areas to store work and street clothing separately. Employers should collect work clothing at the end of each work shift and provide for its laundering. Laundry personnel should be informed about the potential hazards of handling contaminated clothing and instructed about measures to minimize their health risk.

Protective clothing should be kept free of oil and grease and should be inspected and maintained regularly to preserve its effectiveness.

Protective clothing may interfere with the body's heat dissipation, especially during hot weather or during work in hot or poorly ventilated work environments.

REFERENCES

ACGIH [1991]. Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

ACGIH [1994]. 1994-1995 Threshold limit values for chemical substances and physical agents and biological exposure indices. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

Baselt RC [1988]. Biological monitoring methods for industrial chemicals. 2nd ed. Davis, CA: Biomedical Publications.

CFR. Code of Federal regulations. Washington, DC: U.S. Government Printing Office, Office of the Federal Register.

DOT [1993]. 1993 Emergency response guidebook, guide 31. Washington, DC: U.S. Department of Transportation, Office of Hazardous Materials Transportation, Research and Special Programs Administration.

Forsberg K, Mansdorf SZ [1993]. Quick selection guide to chemical protective clothing. New York, NY: Van Nostrand Reinhold.

Genium [1988]. Material safety data sheet No. 683. Schenectady, NY: Genium Publishing Corporation.

Gosselin RE, Smith RP, Hodge HC [1984]. Clinical toxicology of commercial products. 5th ed. Baltimore, MD: Williams & Wilkins.

Hathaway GJ, Proctor NH, Hughes JP, and Fischman ML [1991]. Proctor and Hughes' chemical hazards of the workplace. 3rd ed. New York, NY: Van Nostrand Reinhold.

IARC [1987]. IARC monographs on the evaluation of carcinogenic risk of chemicals to man. Supplement 7. Lyon, France: World Health Organization, International Agency for Research on Cancer.

Mickelsen RL, Hall RC [1987]. A breakthrough time comparison of nitrile and neoprene glove materials produced by different glove manufacturers. Am Ind Hyg Assoc J 48(11): 941-947.

Mickelsen RL, Hall RC, Chern RT, Myers JR [1991]. Evaluation of a simple weight-loss method for determining the permeation of organic liquids through rubber films. Am Ind Hyg Assoc J 52(10): 445-447.

NIOSH [1987a]. NIOSH guide to industrial respiratory protection. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 87-116.

NIOSH [1987b]. NIOSH respirator decision logic. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 87-108.

NIOSH [1992]. Recommendations for occupational safety and health: Compendium of policy documents and statements. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 92-100.

NIOSH [1994a]. NIOSH pocket guide to chemical hazards. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-116.

NIOSH [1994b]. NIOSH manual of analytical methods. 4th ed. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-113.

NIOSH [1995]. Registry of toxic effects of chemical substances: Chlorodiphenyl (54% chlorine). Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, Division of Standards Development and Technology Transfer, Technical Information Branch.

NLM [1995]. Hazardous substances data bank: Chlorodiphenyl (54% chlorine). Bethesda, MD: National Library of Medicine.

OSHA [1994]. Computerized information system. Washington, DC: U.S. Department of Labor, Occupational Safety and Health Administration.

Parmeggiani L [1983]. Encyclopedia of occupational health and safety. 3rd rev. ed. Geneva, Switzerland: International Labour Organisation.

Sittig M [1991]. Handbook of toxic and hazardous chemicals. 3rd ed. Park Ridge, NJ: Noyes Publications.

USC. United States code. Washington. DC: U.S. Government Printing Office.

USCG [1984]. CHRIS (chemical hazards response information system) hazardous chemical data manual: chlorodiphenyl (54% chlorine). Washington, DC: U.S. Department of Transportation, U.S. Coast Guard, Commandant Instruction M16465.12A.

Windholz M, ed. [1983]. Merck Index 10th ed. Rahway, NJ: Merck & Company.