The Phelps-Dodge site, a former copper-smelting operation just outside Douglas, Cochise County, Arizona, posed a public health hazard to children who live in Douglas and possibly Agua Prieta, Sonora, Mexico. This site contributed to lead-contaminated surface soils in residential areas in Douglas. Exposure to the lead-contaminated soils may have contributed and/or caused elevated blood lead levels in children living in both Douglas, AZ and Agua Prieta, Sonora, Mexico. Elevated blood lead levels (above 10 µg/dL) have been associated with a decreased Intelligence Quotient (IQ) and other neurobehavioral health outcomes. In addition, past chronic exposures to smelter emissions may have aggravated respiratory problems in sensitive people, such as children and adults with respiratory ailments.
In 1985, lead contamination in off-site soil (in Douglas) averaged more than 250 mg/kg; and about 350 mg/kg in Pirtleville (the neighborhood in Douglas closest to the site). Results of blood lead testing in children in 1975 and 1985 showed that the childrens' levels exceeded 10 µg/dL on the average. At the time, the levels found did not exceed levels of concern. Since then, the Centers for Disease Control and Prevention (CDC) has lowered its level of concern to 10 µg/dL, since new research indicates that even low levels of lead in the blood may negatively effect health in children. Blood lead levels greater than 10 µg/dL have been associated with decreased IQs, which measure a child's ability to learn. The rates of learning disabilities in Douglas' elementary schools were determined during preparation of this public health assessment; however, more investigation is needed to determine the relationship between the rates and environmental exposure. It is possible that lead contaminated soil in Douglas and Pirtleville could have contributed to elevated blood lead levels in Douglas' and Pirtleville's children.
Past emissions from the smelter included arsenic, lead, sulfur dioxide, inhalable particulate matter, and other heavy metals. The levels detected by air monitoring were elevated above health guidelines. Past exposures to airborne arsenic emissions, if inhaled over a long period of time, may present a low increased risk of lung cancer. Chronic inhalation of inhalable particulate matter and sulfur dioxide are also associated with adverse respiratory effects. A study conducted in 1979 by the University of Utah concluded that there was no increase in mortality associated with lung cancer in Douglas; however, the study had numerous methodologic problems that limit its usefulness for evaluating lung cancer outcomes in the area. A new study of lung cancer deaths (considering various risk factors) is currently underway by the Arizona Department of Health Services.
Along with concerns about contamination of soil and air in Douglas, community members are concerned about numerous health outcomes, including birth defects, collagen diseases, cancer, diabetes, asthma, allergies, ear infections, and poor eyesight in children. The Border Ecology Project (a local activist group) has expressed concerns about heavy metal contamination on site and its potential to migrate off site via Whitewater Draw (an intermittent stream) and underground water. Those concerns are addressed in the Community Health Concerns Evaluation section of this public health assessment.
The petitioner who requested a public health assessment of the Phelps-Dodge smelter was concerned about occupational exposure to asbestos during removal operations at the site in 1990. Workers who did not have or use protective respiratory equipment during demolition were exposed to levels of asbestos that increase their risk of developing lung cancer.
Following its evaluation of site-related information, the Agency for Toxic Substances and Disease Registry (ATSDR) has taken the following steps to protect the public health:
From the findings of a report summarizing a site visit to the Phelps-Dodge smelter (discussed in subsequent sections of this public health assessment), ATSDR accepted a petitioner's request to conduct a public health assessment of the former smelter site. In cooperation with the Arizona Department of Health Services (ADHS), the Agency for Toxic Substances and Disease Registry (ATSDR) has evaluated the public health significance of this site. More specifically, ATSDR has determined whether adverse health effects are possible and has recommended actions to reduce or prevent possible health effects. ATSDR, which is based in Atlanta, Georgia, is a federal agency within the U.S. Department of Health and Human Services authorized by the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) to conduct public health assessments of hazardous waste sites.
A. Site Description and History
The Phelps-Dodge Corporation Douglas Reduction Works is a 2000 acre site whose works are located about 1 mile west of Douglas. Two primary copper smelters operated at the site. The Calumet and Arizona Company Smelter was built in 1902. The Copper Queen operated in Douglas from 1904 until 1931, when the Phelps-Dodge Corporation purchased the Calumet and Arizona Company and took over their smelter. The Calumet and Arizona smelter then became the Douglas Reduction Works. The Douglas Reduction Works operated until January, 1987, (see Figure 1, Appendix 1) (45).
Copper and other metals were smelted at the facility. During the smelting process, the metal ores were heated producing molten metals and releasing sulfur dioxide and particulate matter through two 600-foot stacks (45). Prevailing wind in the area blew south toward Mexico in the evening and north-northeast during the day. The greatest air emissions occurred during the day and decreased in the evening. Air quality monitoring began in 1967; the Arizona Department of Environmental Quality (ADEQ) comprehensive air monitoring program found elevated levels of sulfates, arsenic, and lead particulate in outdoor air in Douglas (3).
The smelter had a history of exceeding allowable stack emission rates for particulate matter and sulfur dioxide gas. It was this failure to comply with the Environmental Protection Agency's (EPA) National Ambient Air Quality Standards (NAAQS) for particulates and sulfur dioxide gas that led to the smelter's closure in 1987 (45). Between 1987 and 1991, the Phelps-Dodge site underwent extensive salvage operations, including removal of all soils with recoverable copper values. The copper recovery operation ultimately resulted in the removal of 15.6 million tons of soil from the site for smelting. Remaining soils were tested for heavy metals, and found to meet Health Based Guidance Levels (HBGLs) as established by ADHS. Other recovery and salvage operations included:
The smelter facilities were demolished in January, 1990. Nonhazardous demolition wastes were deposited in an on-site landfill; hazardous demolition wastes (i.e., asbestos and cyanide) were transported off site (5).
Controversy surrounded the removal operations, which were conducted by Spray Systems International. Employees of Spray Systems claimed they were being occupationally exposed to hazardous levels of asbestos and cyanide. At the time, ADEQ and state Occupational Safety and Health Administration (OSHA) investigations did not substantiate the claims (13). In March 1990, ATSDR received a petition from a Spray System worker requesting a public health assessment of the site.
Currently, there is no sign of the smelter facilities that were once on site; it now looks like typical desert terrain (12). A large pile of slag (solid wastes from processing copper ore) occupies about 200 acres of the site. Three landfills exist on site. Two of the landfills were historical dumping areas that are closed and covered in soil. The third, located on the former Phelps-Dodge property, was a municipal landfill that is now closed. The total landfill area is about 60 acres. Access to the site remains partially restricted. A four-foot, barbed-wire fence surrounds most of the site; the gate is at the access road entrance off U.S. Highway 80. The southern border of the site abuts the US-Mexican Border. The border area was not fenced (the fence was stolen). However, border patrol police use surveillance cameras, motion detectors, and regular vehicle patrols to prevent trespassing (45). The northern border has an eight-foot high chain-linked fence. One access road gate was open off of U.S. Highway 80, and some evidence of trespassing was noted in this area (see discussion in Site Visit section).
Also on site were five wastewater treatment ponds and an acid tank; consequently, ADEQ began monitoring groundwater and surface water in 1980 and 1987, respectively (6). In 1986, EPA conducted a wastewater sampling program. Nine on site, unpermitted discharges of wastewater containing heavy metal contaminants were observed draining to the Whitewater Draw, a small seasonal stream flowing from the Phelps-Dodge site into Mexico. These discharge points were not permitted by EPA because of a court decision which determined that Phelps-Dodge did not discharge to "navigable waters of the United States" (45).
EPA first discovered this site in 1979, and began a Preliminary Investigation in 1983. EPA is currently conducting an expanded Remedial Investigation, under the Comprehensive Environmental Response, Compensation, and Liability Information System (CERCLIS) (45).
In September 1991, ATSDR personnel visited the former Phelps-Dodge site and neighboring community. Because of possible past and current contamination of the surrounding community with heavy metals and the high degree of community concern about possible health effects, ATSDR decided to conduct a public health assessment of the site.
In April 1992, ATSDR completed a site review and update, which addressed lead exposure issues at the site. Recommendations made include: 1) health profession education, 2) community health education, 3) a blood lead screening program for Douglas' children, and 4) off-site surface soil monitoring for heavy metals.
B. Site Visit
During the week of September 16-20, 1991, ATSDR staff members Lynelle Neufer and Joseph Hughart visited the site, gathered site information, and discussed the public health assessment process with local health department staff and the Border Ecology Project, a regional community activist group. ATSDR personnel also reviewed files at ADEQ and ADHS. ATSDR personnel viewed the former smelter site from U.S. Highway 80; the nearby community of Pirtleville was assessed for human exposure pathways.
A second site visit was conducted the week of January 27-29, 1992, by ATSDR staff members Lynelle Neufer, Antonio Quiñones, William Nelson, and Lynn Berlad. The purposes of the second visit were to retrieve health outcome data, assess community health concerns; and revisit the site and surrounding communities.
From U.S. Highway 80, ATSDR personnel noted the following characteristics of the former smelter site:
ATSDR staff also observed the following characteristics of the nearest residential community:
During the site visit, ATSDR staff met with local physicians, concerned community members, and representatives of the Border Ecology Project. Information gathered from those meetings is discussed in the Community Health Concerns and Health Outcome Data sections of this public health assessment.
C. Actions Implemented During the Public Health Assessment Process
ATSDR personnel completed a site review and update for the Phelps-Dodge Smelter site in April 1992. Health profession and community health education were recommended; health education activities were referred to the Division of Health Education. The Health Activities Recommendation Panel (HARP) also recommended that a comprehensive blood lead screening program be considered.
ATSDR implemented an education program for physicians and staff at the Cochise County Health Department in Douglas in October 1992. ATSDR also met with state officials and are coordinating with them in implementing a blood lead screening program for Douglas children.
Because previous lung cancer mortality studies have been inconclusive in their evaluation of lung cancer rates of Douglas and other smelter towns (see the Public Health Implications section), ADHS received funding from ATSDR for a case-control study of lung cancer mortality in smelter towns in Arizona. Researchers will include Douglas in the study. ATSDR will assist in this study as needed.
ATSDR is currently negotiating cooperative efforts at all of the US-Mexican Border sites (including Douglas) with Mexican officials. The goal of these efforts is to coordinate public health assessments and follow-up activities with health professionals in Mexico. The last meeting was held in April, 1994. The purpose of the meeting was to open lines of communication between Mexico and the United States for addressing sites along the US- Mexican Border, such as the Phelps-Dodge site. Because Agua Prieta, Mexico also borders the Phelps-Dodge site, officials from Mexico discussed conducting parallel public health activities for Agua Prieta residents. These activities may include health education for health care providers and community members, and environmental sampling.
In August, 1994, ATSDR participated in the annual Douglas CARE Fair. ATSDR distributed fact sheets (in both English and Spanish) and discussed the need for blood lead screening in young children with over 100 parents. ATSDR also participated in health professions education for health officials from Agua Prieta at this time. The education program was facilitated through the Cochise County Health Department and the Binational Health Coalition.
D. Demographics, Land Use, and Natural Resource Use
Demographics
According to 1990 U.S. Census data, Douglas, Arizona, had a population of 12,822; 83% of the population were Hispanic, 15% were caucasian, and 2% were of other ethnic origin. Douglas is primarily a low- to middle-income community; 20% of the population lives below the poverty level. Forty-eight percent of the population are high school graduates, and 10% have completed at least 4 years of college (1980). Douglas age groups are evenly distributed; 34% are younger than 18 years, 52% are between 18 and 64, and 14% are 65 or older. The northeast Sonora Cochise County Health Council report the combined population of Douglas and Agua Prieta is about 90,000.
Pirtleville, a small Mexican-American neighborhood northeast of the former Phelps-Dodge smelter, is the residential area closest to the site (about a mile east). This newer low- to middle-income community has a population of about 1200 (8). Faras Elementary School, which has 158 students, is in Pirtleville (Appendix A) (14).
Land Use
Pirtleville's Faras Elementary School is about 1.4 miles northeast of the former smelter. Several other schools in Douglas, including Sarah Miley, Clawson, and A Avenue elementary schools, are more than 2 miles away from the former air emission stacks (7).
Several small businesses are about 2 miles east of the former air emission stacks; the only local industry is an oil storage facility, which is about a mile and a quarter east (7).
No major farming operations are near the site; however, several ranches are in the desert near Douglas. The nearest is about 4 miles north of the former smelter (7). In addition, ATSDR staff saw gardens at residences in Pirtleville. Crops included corn and cabbages. Watermelons and corn were seen on the ground at a vendor stand along the outskirts of Pirtleville, within view of the site.
The Southeast Arizona Medical Center is about 2 miles east of the former smelter. Another hospital is approximately 2.5 miles east (7).
Natural Resources Use
The Douglas basin area includes about 1,200 square miles in the southern part of Sulphur Springs Valley, in southeastern Arizona. The valley floor, which occupies about 500 square miles, is underlain by alluvium (material deposited by moving water) that consists of permeable layers of gravel and sand interbedded with relatively impermeable silt and clay. The area is drained by Whitewater Draw, a stream that starts in the northeastern part of the area, flows westward into the valley, southward through the valley, and across the international boundary into Mexico. Through most of the area, Whitewater Draw and its tributaries flow only after precipitation and snowmelt (42).
Whitewater Draw is the only significant surface water body in the area; it runs down the eastern border of the site, then crosses the border where it becomes the Rio Agua Prieta, a perennial body of water (7). ATSDR received no reports of fishing or recreation in the area (11). The stream was dry during ATSDR site visits; fishing is unlikely because the stream appears only during rainstorms. In the past, Phelps-Dodge discharged between 0.4 and 2 million gallons per day of low-level contaminated waste waters into Whitewater Draw. The discharges were not permitted, because of a 1975 Federal Court decision that Phelps-Dodge did not discharge pollutants to navigable waters of the United States (Whitewater Draw never left the site before entering Mexico)(45).
The main source of water for Douglas is the groundwater that underlies Sulphur Springs Valley. The alluvium is at least 1,600 feet thick in the central part of the valley; it thins to a few feet along the mountain fronts. Depths to groundwater are the shallowest near Whitewater Draw, and vary from 44-177 feet in the vicinity of the site. This aquifer is also the source of the City of Douglas municipal water supply. The groundwater flow direction is from the mountain highlands toward the central portion of the valley, and then south into Mexico. Extractions from the groundwater system have resulted in pumping depressions that alter the natural flow, and shift it to the southeast and toward the extraction wells located in Douglas. The city operates eight municipal water supply wells within four miles of the site. The Department of Water Resource Well Data reports there are 122 private wells within a four mile radius of the site (45).
The climate of Douglas is characteristic of the dry desert climate of the Rio Yaqui Basin. On average, the annual rainfall totals 11.14 inches; the relative humidity is 30% (28). Vegetation is relatively sparse; surface soils are dry and consist of silty sand and gravel (9). The average annual wind speed is 8.3 mph and from the southeast out of Agua Prieta, Sonora, Mexico; winds shift and blow towards Mexico in the evening (28). Agua Prieta is less than a mile south of the site. Given the dryness of surface soils and the unpaved roads in Agua Prieta, the windy and dry weather is reported to generate moderate to heavy amounts of ambient dust in Douglas (11).
E. Health Outcome Data
Government and other agencies have collected information on the health of various populations. Health data relevant to this public health assessment are presented here, summarized in Tables 8 and 9, Appendix B, and evaluated in the Health Outcome Evaluation section.
Numerous environmental health studies have been conducted in southern Arizona; many of them included Douglas.
The Douglas community also has been active in generating health outcome data. The school health nurse reported and analyzed a cluster of autoimmune diseases in the Faras Elementary School in Pirtleville in 1991 (14). A Pirtleville resident is documenting first trimester spontaneous abortions in Douglas women (11). Recently, another school health nurse reported percentages of learning disabled and developmentally delayed children in Douglas elementary schools (5).
Currently, ADHS maintains cancer and birth defects registries for the state. In cooperation with ATSDR, the state health department also is planning a lung cancer mortality study that will include Douglas.
A case history at the local health department reported a single blood lead level in a 3-year-old
child. The child presented with complaints of bone pain and was subsequently tested for lead
poisoning. The child's level was 30 µg/dL, three times CDC's recommended level (31).
Residents and officials of Douglas, AZ expressed the following health-related concerns:
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