PUBLIC HEALTH ASSESSMENT
ASARCO INCORPORATED (GLOBE PLANT)
DENVER, DENVER COUNTY, COLORADO
The ASARCO Inc., Globe site in Denver, Denver/Adams County, Colorado, has a long history of smelting operations. The Globe Plant began producing gold, silver, lead and copper in 1886. The American Smelting and Refining Company (ASARCO, Inc.) purchased the plant and converted it for lead smelting in 1901. From 1922 until 1926, arsenic trioxide was produced. In 1926, cadmium production began and continued until 1991. The cadmium circuit was discontinued entirely in June 1993.
The Agency for Toxic Substances and Disease Registry (ATSDR) considers this site a public health hazard based on the evidence that exposures to contaminants at concentrations that might cause adverse health effects have occurred in the past, might be occurring now, or are likely to occur in the future. Workers at the site were exposed to cadmium, tellurium, and lead in indoor air at levels of public health concern. In addition, workers who were in close contact with surface soils were possibly exposed in the past, are being possibly exposed now, and may be exposed in the future to arsenic, cadmium and lead at levels of public health concern. It is possible that these workers might experience some respiratory, kidney and blood problems because of exposure to arsenic tellurium, cadmium and lead in air and/or soils.
Nearby residents were and might be currently exposed to arsenic, cadmium, lead and zinc in soils and vegetables at levels of public health concern. It is possible that adults might experience some respiratory, mild eye and skin irritations, minor changes in skin, kidney, and blood problems. Children, especially the very small number who exhibit pica behavior (1-3 years old) might experience mild neurological signs including eye and skin irritations, and minor skin and blood problems. Past exposures to arsenic in air and soils on site, and to cadmium in air both on and off site might result in slightly low or no apparent increased risk of excess cancer. Although vegetable gardens were a route of exposure in the past, the State of Colorado and ASARCO, Inc. have been actively involved in educating the community about using clean soil and community gardens to avoid any unnecessary exposure.
It is probable that the city-wide problem of total suspended particulate (TSP) levels occasionally exceeding the TSP standard might contribute to the occurrence of respiratory conditions reported and diagnosed among workers and area residents.
Past health studies conducted at the site, and discussed in this public health assessment suggest that about eight percent (37) of the 443 children tested from four neighborhoods in Globeville and Denver including control area have a blood lead level equal to or greater than 10 µg/dl which is the Centers for Disease Control's action level for community intervention. In addition, a Globeville child is more likely than other children to be in the 5 - 10 µg/dl range for blood lead levels although the source of the lead exposure is unknown. The medical monitoring program planned in the community prior to and after soil cleanup will correlate each child's blood lead and urine arsenic and cadmium levels with soil metal levels from each child's yard, especially in the target areas. As part of the Consent Decree, the Colorado Central Cancer Registry will evaluate the cancer levels in the area surrounding the site to determine whether cancer rates are higher than expected when compared to the rates for the city, state, and country.
The community will be monitored prior to and after clean-up of community and residential soils. In addition to those who currently reside in the area, blood and urine testing for arsenic, cadmium, and lead will be offered to all persons who currently work in or have ever worked/lived in the site area or otherwise feel they have potentially been exposed to contaminants from the site. Urine beta-2-microglobulin and indicators of iron deficiency will be provided prior to and after remediation.
Community members raised several concerns related to the ASARCO Inc. Globe Plant site which have been summarized and addressed in the Public Health Implications section of this public health assessment. The ASARCO, Inc. (Globe Plant) Public Health Assessment was available for public review and comment from approximately November 18, 1994 to January 6, 1995. A summary of comments received during the public comment period are presented along with ATSDR's responses in Appendix F.
The Colorado Department of Health and Environment (CDPHE) will take the lead, and ATSDR will assist when requested, to (1) provide community health education to help the exposed persons in understanding their probable exposure, (2) provide health profession education to assist the local health professionals in diagnosing, treating and preventing injury or disease due to exposure to hazardous substances, (3) conduct medical monitoring of the community prior to and after site remediation to evaluate health concerns and assess likelihood of linkage to exposure to hazardous substances, and (4) bring the concerns about childhood respiratory disease in the community to the attention of the local health officials. [The CDPHE has acknowledged that representatives of the local health departments are actively involved in site activities, and have been provided with copies of the public health assessment].
ATSDR has made recommendations to reduce and prevent exposure to contaminants, better characterize the site, and implement institutional controls and other activities. If pertinent additional data and information become available, ATSDR will reevaluate this site for any indicated followup.
The Agency for Toxic Substances and Disease Registry (ATSDR), located in Atlanta, Georgia, is a federal agency within the U.S. Department of Health and Human Services. ATSDR is required by the Superfund law (Comprehensive Environmental Response, Compensation, and Liability Act of 1980 [CERCLA]) as amended by Superfund Amendments and Reauthorization Act of 1986 (SARA) to conduct public health assessments of hazardous waste sites proposed for the National Priorities List (NPL). In response to EPA's proposed listing of the ASARCO Globe plant site in Denver, Colorado, ATSDR has, in cooperation with the local, state, and other federal agencies, evaluated the public health significance of the site.
A. Site Description and History
The 92 acre ASARCO Inc. Globe Plant site in north Denver (495 East 51st Street) straddles the boundary between Denver and Adams County, Colorado (Figure 1, Appendix A), in an area along the west edge of the South Platte River floodplain (1). Although the southeast portion of the site is in the floodplain, most of the site lies on the terrace, a surface topographic high running northeast/southwest. The Globe plant includes 53 buildings used for either production, office space, or wastewater treatment (Figure 2, Appendix A). Historically, ASARCO also owned 50 acres (based on a 1925 survey) east of its current property, known as the ASARCO Annex (1).
The Globe Plant began producing gold, silver, lead and copper in 1886. The American Smelting and Refining Company (renamed ASARCO Inc. in 1975) bought the site in 1901 and converted the plant to lead smelting, which continued until about 1919. At that time, the plant was converted to produce refined arsenic trioxide. Arsenic trioxide production was principally carried out from 1922 until 1926. In 1926, cadmium production began and was discontinued entirely in June 1993 (2,3).
The materials present in greatest volume at the ASARCO Inc. Globe Plant site include the slag from the lead smelting operation and the solid precipitate material from the former neutralization pond, which is unlined. The lead slag was deposited on the floodplain portion of the site and at the ASARCO Annex (2). The slag deposit is approximately 15 feet thick and 1700 feet in length. The precipitates in the former neutralization pond area resulted from the addition of lime to raise the Ph of spent process solutions generated by the cadmium refining operations (2). The resultant slurry solution was discharged to the neutralization pond where the precipitates settled and formed a gradually increasing mound which eventually measured seven acres by eight feet high (2). In May 1986, the neutralization pond was taken out of service. The area was regraded and covered with six inches of clayey soil, and vegetated with native grass to prevent blowing of precipitates and to minimize infiltration of rain water (2).
The Colorado Department of Health and Environment (CDPHE) Water Quality Control Division collected water and sediment samples from the Industrial Drainage Ditch (IDD) in 1974 and detected elevated concentrations of cadmium, lead and other metals (1). In 1980 and 1981, CDPHE found the site to be out of compliance with the Colorado Solid Waste Disposal Sites and Facilities Act. Subsequent to the investigations and inspections conducted by the CDPHE, the Environmental Protection Agency (EPA) listed the ASARCO Globe Plant on the open dump inventory for 1981 under the Resource Conservation and Recovery Act (RCRA) (1). The Hart Field Investigation Team (FIT) sampled soils, sediments, wastes, and surface water at the site and vicinity in December 1982. Three ground water monitoring wells were installed on site during this time (1).
In September 1992, the EPA National Enforcement Investigations Center conducted airborne particulate sampling on the Plant property. The study focused on suspended particulates as well as cadmium and lead. Other metals, such as antimony, beryllium, chromium, nickel, selenium, and thallium were at concentrations at or below detection levels (4).
A comprehensive Remedial Investigation (RI) (2), Public Health Evaluation (PHE) (5) and Feasibility Study (FS) (6) were conducted as part of a joint investigation of the Globe Plant site by ASARCO and its consultants with oversight and assistance by CDPHE and its consultants. The objectives of the RI were to determine the extent, magnitude, sources, and impacts, if any, of contamination due to releases of hazardous substances from the site, and to gather necessary data to assist in preparation of the PHE and the FS. The RI consisted of six tasks including a source inventory, air monitoring, and investigations of ground water, surface water, soil, and vegetation at the site. The RI was finalized on March 12, 1992 (1).
The PHE evaluated the potential impact on human health from the site if no remedial actions were to occur. Four indicator chemicals were selected for final evaluation: arsenic, cadmium, lead and zinc (5).
The purpose of the FS was to develop and evaluate alternatives to address public health, environmental and social concerns posed by the release of hazardous substances from the Globe Plant. The FS report was finalized on May 29, 1992 (6). After a public comment period for the FS, the most appropriate alternatives evaluated were selected and presented for public consideration in the Proposed Plan for Cleanup of the ASARCO Globe Plant site dated October 1992. After receipt and consideration of public comments on the Proposed Plan, the selected remedial alternatives were documented in the CDPHE Record of Decision (ROD) dated February 18, 1993 (1).
The Consent Decree dated May 3, 1993, presented the Statement of Work (SOW) for the design and implementation of the Remedial Action at the ASARCO Globe Plant Site. The proposed remedies address four areas of contamination identified in previous studies (RI/FS, Public Health Evaluation): the former neutralization pond; ground water/surface water; community soils and vegetable gardens, and plant site and air emissions (4).
In addition, a medical monitoring program is being provided to evaluate possible exposure and the health status of residents who currently live near or have previously lived near the Globe Plant (1). Further description of this program is provided in the Health Outcome Data section of this public health assessment.
The State of Colorado sued ASARCO Inc. in December 1983 under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980 (7). This lawsuit was filed for damage to natural resources and risk to public health. The settlement included remedial measures to reduce contamination and an agreement to conduct medical monitoring services (7). In addition, a private class action lawsuit went to trial in February 1993. That lawsuit represented residential property owners and former Stapleton Homes residents. The settlement awarded clean up and property damages (cash awards) to residents owning property in a specific geographic region (defined by 60th Avenue to the north, Franklin and the Platte River to the east, Interstate Highway 70 to the south, and Interstate Highway 25 to the west) in April 1993 and a cash award for the 1991 relocated residents of Stapleton Homes. The cash award and soil remediation will be paid for by ASARCO, Inc., and independent contractors will be employed for remedial activities, with technical oversight to be determined by the class action members (7).
ATSDR, in cooperation with the CDPHE, has been involved with the ASARCO Globe plant site in the past. In 1986, at the request of CDPHE, ATSDR reviewed the remedial investigation work plan devised by the State of Colorado for the ASARCO Globe smelter in Denver, Colorado and prepared comments on the public health significance of soil contamination levels (8). In addition, ATSDR, in cooperation with CDPHE, funded the Exposure Assessment for the Globeville Community which occurred from September 1989 to March, 1991. In December 1992, ATSDR released a health consultation for the ASARCO Globe Plant site, in response to the State's proposed cleanup level of 73 parts per million (ppm) for cadmium in soil (9).
Remedial Actions Completed to Date
A number of remedial actions have been implemented by ASARCO during the course of the RI. These actions include (1,10):
In addition, the following actions occurred after the completion of the RI:
On November 30, 1993, ATSDR Headquarters personnel, Dr. Mark Rodriguez and Ms. Laura Barr, ATSDR Region VIII Representative Dr. Glenn Tucker, accompanied by CDPHE representatives and the State of Colorado Assistant Attorney General for the Natural Resource Section attended a site visit tour of the ASARCO Globe Plant. The ASARCO Site Manager conducted the tour, which included a description of past metals refining operations (including the cadmium process) and current metal operations (lead oxide, bismuth oxide, and other metals). In addition, the group drove around the perimeter of the Globe plant and the surrounding community. ATSDR personnel made the following observations:
On December 1 and 2, 1993, ATSDR staff with participation of CDPHE staff performed four public availability meetings to gather environmental and health concerns from the community about the ASARCO Globe plant site. An ATSDR press release announced the availability meetings. Approximately fifty people attended the public availability sessions. On December 1, ATSDR also met with directors of the local Family Resource Center.
C. Demographics, Land Use, and Natural Resource Use
Demographics
Globeville
The Globeville community (census tract 15) extends southward from the Denver/Adams County line and is bounded by the South Platte River to the east and south, and Inca Street to the west. The 1988 estimated population was 3612 (Denver Planning Office, 1988) (12). The 1985 estimated population of the area north of the Globe plant, specifically the portion of Adams County south of Clear Creek between York Street and Pecos Street, was 915 (Adams County Planning Office, 1988) (1). Approximately 53% of the Globeville population is of Hispanic origin (U.S. Department of Commerce, 1983) (12).
The 1990 census population for census tract 15 is relatively similar to 1988 estimates with a reported population of 3455, with approximately 67% of the population Hispanic in origin (13).
The Stapleton Homes public housing (234 units) was located across the street from the ASARCO Globe Plant's western boundary. Approximately 300 children lived in the Stapleton Homes public housing who were less than 18 years old. The Stapleton Housing Project constructed in the 1950's was closed in 1990 and demolished during the winter of 1991-92 (12,14).
Since the 1950's, Laradon Hall Training School has been in operation as a school and training facility for approximately 400 mentally retarded or differently-abled youths who lived in and/or attended the facility (12,14). The school is about three blocks from the Globe Plant.
Elyria and Swansea
A broader definition of Globeville includes the neighborhoods of Elyria and Swansea (Census tract 35) to the east of the Platte River. The 1986 population estimate of Elyria-Swansea is 5285, with approximately 60% of Hispanic origin (U.S. Department of Commerce, 1983) (12). The 1990 census population for census tract 35 reported 5055 people, with 73% of Hispanic origin. It is believed by the CDPHE that distance, in addition to the Platte River wind/drainage system, protects Elyria and Swansea from ASARCO Globe plant emissions. However, there is concern among the residents that the ASARCO Globe plant poses potential health threats to them (12). The planned cleanup process is aimed at addressing this potential health threat.
Summary statistics of population within one mile of the site consists of 693 children 5 years or younger, 461 adults 60 years or older, 897 females aged 15-44 years, 399 African Americans, 61 American Indians, 54 Asians, and 2824 Hispanics.
Land Use
The Globe plant is located in a mixed land use area. Within a one mile radius of the plant, 9.5 percent of the land is residential and 1.0 percent is used for farming. The remaining 89.5 percent is commercial and industrial, with 4.5 percent occupied by the plant. Residential areas immediately adjacent to the plant are located to the southwest and southeast. A mixed residential and commercial area is north of the plant, along 55th Avenue (1).
Interstate 70 and Interstate 25 (south and west of the site, respectively) are the two main interstate highways used by approximately 250,000 vehicles daily. These interstates have been in operation since the late 1950's and mid 1960's (14).
The Northside Treatment Plant is located at the far northeast corner of East Globeville. The plant is no longer in service (14).
Natural Resource Use
Two principal groundwater systems exist in the Globe Plant area: 1) a shallow system in sand and gravel deposits and shallow weathered sandstone, and 2) a deeper system in permeable beds of the Denver Basin bedrock formations. The shallow groundwater system is underlain by an extensive, low permeability claystone deposit of the Denver formation. Groundwater flows southeast in the shallow aquifer beneath the site until it enters the floodplain at the southeast portion of the site where it then flows northeast. The deep bedrock aquifers beneath the site area are separated from the shallow ground water system by more than 70 feet of low permeability claystone. Therefore, water in the deep aquifer should not be influenced by shallow groundwater contamination. Deep groundwater flow below the site is eastward toward a low point in the water table created by several decades of well pumping in the Denver area (1).
Surface water bodies and flow systems in the Globe Plant area include the South Platte River, an Industrial Drainage Ditch west of the site, and the Farmers and Gardeners Ditch. The major surface water body in the area is the South Platte River that flows from the central Rocky Mountains north through Denver to its confluence with the North Platte River in Nebraska. The small ditch originating west of the Globe Plant, known as the Industrial Drainage Ditch, flows along the west boundary of the Plant through the Retention Ponds to 51st Avenue, where it discharges to a storm sewer. The storm sewer flows to a Detention Pond in the floodplain, and the Detention Pond discharges through an overflow pipe to the South Platte River. The Farmers and Gardeners Ditch (FGD) conveys water to the northeast along the edge of the terrace through a buried three foot diameter concrete pipe (1). Parts of the central Globeville residential area and most of the east Globeville Industrial and business area on Washington Street lie within the South Platte River 100-year flood plain (14).
Health outcome data are used in a public health assessment to help identify whether there is higher than expected amount of adverse health effects in the area around the site. Health outcome data can include information on cancer incidence or birth defects, clinical testing, medical exams, school records, and epidemiological investigations.
Health outcome data evaluated for this public health assessment include the following:
Databases
Public availability sessions were held at the Laradon Hall on Lincoln Street on December 1 and December 2, 1993. Approximately 50 people from the community surrounding the ASARCO Globe Plant or who lived in the area in the past attended one-to-one meetings with ATSDR headquarters staff. Spanish speaking staff were available for those families that only spoke Spanish. The CDPHE staff were also available during the availability meetings to answer community questions pertaining to the proposed medical monitoring program, off-site soil sampling and remediation, and any other question pertaining to the clean-up.
The concerns identified were:
Other comments expressed by the community are the following:
These concerns will be addressed in the Community Health Concerns Evaluation portion of the Public Health Implications Section.
Next Section Table of Contents
