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 ofsmelting operations. The Globe Plant began producing gold, silver, lead and copper in 1886. The American Smelting and Refining Company (ASARCO, Inc.) purchased the plant andconverted 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 wasdiscontinued entirely in June 1993.
The Agency for Toxic Substances and Disease Registry (ATSDR) considers this site a publichealth hazard based on the evidence that exposures to contaminants at concentrations that mightcause adverse health effects have occurred in the past, might be occurring now, or are likely tooccur in the future. Workers at the site were exposed to cadmium, tellurium, and lead in indoorair at levels of public health concern. In addition, workers who were in close contact withsurface soils were possibly exposed in the past, are being possibly exposed now, and may beexposed in the future to arsenic, cadmium and lead at levels of public health concern. It ispossible that these workers might experience some respiratory, kidney and blood problemsbecause 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 soilsand vegetables at levels of public health concern. It is possible that adults might experiencesome respiratory, mild eye and skin irritations, minor changes in skin, kidney, and bloodproblems. 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 andblood problems. Past exposures to arsenic in air and soils on site, and to cadmium in air both onand off site might result in slightly low or no apparent increased risk of excess cancer. Althoughvegetable 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 communitygardens to avoid any unnecessary exposure.
It is probable that the city-wide problem of total suspended particulate (TSP) levels occasionallyexceeding 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 suggestthat about eight percent (37) of the 443 children tested from four neighborhoods in Globevilleand Denver including control area have a blood lead level equal to or greater than 10 µg/dl whichis the Centers for Disease Control's action level for community intervention. In addition, aGlobeville child is more likely than other children to be in the 5 - 10 µg/dl range for blood leadlevels although the source of the lead exposure is unknown. The medical monitoring programplanned in the community prior to and after soil cleanup will correlate each child's blood leadand urine arsenic and cadmium levels with soil metal levels from each child's yard, especially inthe target areas. As part of the Consent Decree, the Colorado Central Cancer Registry willevaluate 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 everworked/lived in the site area or otherwise feel they have potentially been exposed tocontaminants 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 sitewhich have been summarized and addressed in the Public Health Implications section of thispublic health assessment. The ASARCO, Inc. (Globe Plant) Public Health Assessment wasavailable 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 alongwith ATSDR's responses in Appendix F.
The Colorado Department of Health and Environment (CDPHE) will take the lead, and ATSDRwill assist when requested, to (1) provide community health education to help the exposedpersons in understanding their probable exposure, (2) provide health profession education toassist the local health professionals in diagnosing, treating and preventing injury or disease due toexposure to hazardous substances, (3) conduct medical monitoring of the community prior to andafter 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 thecommunity to the attention of the local health officials. [The CDPHE has acknowledged thatrepresentatives 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, bettercharacterize the site, and implement institutional controls and other activities. If pertinentadditional data and information become available, ATSDR will reevaluate this site for anyindicated 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 requiredby the Superfund law (Comprehensive Environmental Response, Compensation, and LiabilityAct of 1980 [CERCLA]) as amended by Superfund Amendments and Reauthorization Act of1986 (SARA) to conduct public health assessments of hazardous waste sites proposed for theNational Priorities List (NPL). In response to EPA's proposed listing of the ASARCO Globeplant site in Denver, Colorado, ATSDR has, in cooperation with the local, state, and other federal agencies, evaluated the public health significance of the site.
The 92 acre ASARCO Inc. Globe Plant site in north Denver (495 East 51st Street) straddles theboundary between Denver and Adams County, Colorado (Figure 1, Appendix A), in an areaalong the west edge of the South Platte River floodplain (1). Although the southeast portion ofthe site is in the floodplain, most of the site lies on the terrace, a surface topographic highrunning northeast/southwest. The Globe plant includes 53 buildings used for either production,office space, or wastewater treatment (Figure 2, Appendix A). Historically, ASARCO alsoowned 50 acres (based on a 1925 survey) east of its current property, known as the ASARCOAnnex (1).
The Globe Plant began producing gold, silver, lead and copper in 1886. The American Smeltingand Refining Company (renamed ASARCO Inc. in 1975) bought the site in 1901 and convertedthe plant to lead smelting, which continued until about 1919. At that time, the plant wasconverted to produce refined arsenic trioxide. Arsenic trioxide production was principallycarried out from 1922 until 1926. In 1926, cadmium production began and was discontinuedentirely in June 1993 (2,3).
The materials present in greatest volume at the ASARCO Inc. Globe Plant site include the slagfrom the lead smelting operation and the solid precipitate material from the former neutralizationpond, which is unlined. The lead slag was deposited on the floodplain portion of the site and atthe ASARCO Annex (2). The slag deposit is approximately 15 feet thick and 1700 feet inlength. The precipitates in the former neutralization pond area resulted from the addition of limeto raise the Ph of spent process solutions generated by the cadmium refining operations (2). Theresultant slurry solution was discharged to the neutralization pond where the precipitates settledand formed a gradually increasing mound which eventually measured seven acres by eight feethigh (2). In May 1986, the neutralization pond was taken out of service. The area was regradedand 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 Divisioncollected water and sediment samples from the Industrial Drainage Ditch (IDD) in 1974 anddetected 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 andFacilities Act. Subsequent to the investigations and inspections conducted by the CDPHE, theEnvironmental Protection Agency (EPA) listed the ASARCO Globe Plant on the open dumpinventory for 1981 under the Resource Conservation and Recovery Act (RCRA) (1). The HartField Investigation Team (FIT) sampled soils, sediments, wastes, and surface water at the siteand vicinity in December 1982. Three ground water monitoring wells were installed on siteduring this time (1).
In September 1992, the EPA National Enforcement Investigations Center conducted airborneparticulate sampling on the Plant property. The study focused on suspended particulates as wellas 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) andFeasibility Study (FS) (6) were conducted as part of a joint investigation of the Globe Plant siteby 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, ofcontamination due to releases of hazardous substances from the site, and to gather necessary datato assist in preparation of the PHE and the FS. The RI consisted of six tasks including a sourceinventory, 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 actionswere 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 GlobePlant. The FS report was finalized on May 29, 1992 (6). After a public comment period for theFS, the most appropriate alternatives evaluated were selected and presented for publicconsideration in the Proposed Plan for Cleanup of the ASARCO Globe Plant site dated October1992. After receipt and consideration of public comments on the Proposed Plan, the selectedremedial alternatives were documented in the CDPHE Record of Decision (ROD) dated February18, 1993 (1).
The Consent Decree dated May 3, 1993, presented the Statement of Work (SOW) for the designand implementation of the Remedial Action at the ASARCO Globe Plant Site. The proposedremedies address four areas of contamination identified in previous studies (RI/FS, Public HealthEvaluation): the former neutralization pond; ground water/surface water; community soils andvegetable gardens, and plant site and air emissions (4).
In addition, a medical monitoring program is being provided to evaluate possible exposure andthe health status of residents who currently live near or have previously lived near the GlobePlant (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 ComprehensiveEnvironmental Response, Compensation, and Liability Act (CERCLA) of 1980 (7). This lawsuitwas filed for damage to natural resources and risk to public health. The settlement includedremedial measures to reduce contamination and an agreement to conduct medical monitoringservices (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. Thesettlement awarded clean up and property damages (cash awards) to residents owning property ina specific geographic region (defined by 60th Avenue to the north, Franklin and the Platte Riverto the east, Interstate Highway 70 to the south, and Interstate Highway 25 to the west) in April1993 and a cash award for the 1991 relocated residents of Stapleton Homes. The cash award andsoil remediation will be paid for by ASARCO, Inc., and independent contractors will beemployed for remedial activities, with technical oversight to be determined by the class actionmembers (7).
ATSDR, in cooperation with the CDPHE, has been involved with the ASARCO Globe plant sitein the past. In 1986, at the request of CDPHE, ATSDR reviewed the remedial investigation workplan devised by the State of Colorado for the ASARCO Globe smelter in Denver, Colorado andprepared comments on the public health significance of soil contamination levels (8). Inaddition, ATSDR, in cooperation with CDPHE, funded the Exposure Assessment for theGlobeville Community which occurred from September 1989 to March, 1991. In December1992, ATSDR released a health consultation for the ASARCO Globe Plant site, in response tothe State's proposed cleanup level of 73 parts per million (ppm) for cadmium in soil (9).
Remedial Actions Completed to Date
- construction of a new wastewater treatment plant in June 1986;
- repairs to the Farmers and Gardeners Ditch (FGD) pipe in 1987 and 1988 to reduce theconcentration of cadmium in the ditch water to levels that meet CDPHE irrigation waterstandards;
- installation of a ground water interception drain adjacent to the FGD in the summer of 1988 to prevent ground water infiltration into the pipe;
- regrading and covering of the Former Neutralization Pond with six inches of clayey soil andvegetation in 1986 to prevent blowing of precipitates and to minimize infiltration of rainwater;
- provision of city water to a residence south of the Globe Plant site to replace contaminated shallow ground water supplies;
- installation of improved air emissions controls and elevation of stack heights in 1987 and 1988, respectively;
- installation of additional baghouses at the litharge department and the cadmium retort department in 1989;
- excavation and removal of a tile pipe in 1985 which conveyed water from an unknown source to the Industrial Drainage Ditch (IDD); and
- installation of security fencing around the IDD in 1985.
In addition, the following actions occurred after the completion of the RI:
- cessation of the cadmium premelt process operation in 1991 (3);
- cessation of the cadmium and cadmium oxide production (retort department) in 1993 (3); and
- community surface soil sampling (0 - 2 inches, 0 - 6 inches) initiated during the fall of 1993 withpriority given to schools, parks, and day care centers for the design investigation to further define areas to be remediated (11, 21).
On November 30, 1993, ATSDR Headquarters personnel, Dr. Mark Rodriguez and Ms. LauraBarr, ATSDR Region VIII Representative Dr. Glenn Tucker, accompanied by CDPHErepresentatives and the State of Colorado Assistant Attorney General for the Natural ResourceSection attended a site visit tour of the ASARCO Globe Plant. The ASARCO Site Managerconducted the tour, which included a description of past metals refining operations (including thecadmium process) and current metal operations (lead oxide, bismuth oxide, and other metals). Inaddition, the group drove around the perimeter of the Globe plant and the surroundingcommunity. ATSDR personnel made the following observations:
- The ASARCO Globe Plant site is entirely fenced with a seven foot fence and has a guard at the front gate.
- The Industrial Drainage Ditch on the west side of the plant is fenced and signs are posted stating "Danger, No Trespassing" as is the ASARCO Plant east perimeter fence facing Washingtonstreet.
- Unused tanks remain in the cadmium circuit.
- The residential areas located south, north, and east of the site are composed of middle- andlow-income housing with numerous trailer homes (northeast). The area is also interspersed withsmall commercial businesses and industries, including foam/plastics, cement, and meat packingcompanies near the site.
- Several of the residential yards were used for auto salvage or the storage of other miscellaneous items such as signs.
- Children under the age of five were observed playing in yards lacking grass and composedprimarily of dirt.
- Sampling of soil on property located between 50th Street and Lincoln Street was observed during the site visit.
On December 1 and 2, 1993, ATSDR staff with participation of CDPHE staff performed fourpublic availability meetings to gather environmental and health concerns from the communityabout the ASARCO Globe plant site. An ATSDR press release announced the availabilitymeetings. Approximately fifty people attended the public availability sessions. On December 1, ATSDR also met with directors of the local Family Resource Center.
The Globeville community (census tract 15) extends southward from the Denver/Adams Countyline 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 1985estimated population of the area north of the Globe plant, specifically the portion of AdamsCounty south of Clear Creek between York Street and Pecos Street, was 915 (Adams CountyPlanning 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 ASARCOGlobe Plant's western boundary. Approximately 300 children lived in the Stapleton Homespublic housing who were less than 18 years old. The Stapleton Housing Project constructed inthe 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 trainingfacility for approximately 400 mentally retarded or differently-abled youths who lived in and/orattended 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 (Censustract 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). The1990 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.
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 interstatehighways used by approximately 250,000 vehicles daily. These interstates have been inoperation 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 sandand gravel deposits and shallow weathered sandstone, and 2) a deeper system in permeable bedsof the Denver Basin bedrock formations. The shallow groundwater system is underlain by anextensive, low permeability claystone deposit of the Denver formation. Groundwater flowssoutheast in the shallow aquifer beneath the site until it enters the floodplain at the southeastportion of the site where it then flows northeast. The deep bedrock aquifers beneath the site areaare separated from the shallow ground water system by more than 70 feet of low permeabilityclaystone. Therefore, water in the deep aquifer should not be influenced by shallowgroundwater contamination. Deep groundwater flow below the site is eastward toward a lowpoint 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, anIndustrial Drainage Ditch west of the site, and the Farmers and Gardeners Ditch. The majorsurface water body in the area is the South Platte River that flows from the central RockyMountains north through Denver to its confluence with the North Platte River in Nebraska. Thesmall ditch originating west of the Globe Plant, known as the Industrial Drainage Ditch, flowsalong the west boundary of the Plant through the Retention Ponds to 51st Avenue, where itdischarges to a storm sewer. The storm sewer flows to a Detention Pond in the floodplain, andthe Detention Pond discharges through an overflow pipe to the South Platte River. The Farmersand Gardeners Ditch (FGD) conveys water to the northeast along the edge of the terrace througha 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 ishigher than expected amount of adverse health effects in the area around the site. Healthoutcome 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:
- A cross-sectional survey ( June 1976) of a community near a cadmium smelter (Globeville) inDenver, Colorado (15);
- The Colorado Central Cancer Registry Report of Cancer Incidence for 1980-83 in census tracts surrounding ASARCO Globe Plant (16);
- The Colorado Central Cancer Registry Report for 1980-86 for age-adjusted cancer incidencerates in census tracts (15,35,89.52) surrounding the ASARCO Globe Plant site (17);
- A Public Health Evaluation conducted jointly by the State of Colorado and ASARCO, Inc. aspart of the Remedial Investigation of environmental contamination at the ASARCO Globe Plantsite and surrounding area (5);
- The Globeville Childhood Metals Study: An Exposure Study (November 15, 1993) (12);
- Information on Central Cancer Registry (April 28, 1993) for the entire Denver Metro area,including the three census tracts which encompass the Globe area is available for the years1979-90 (18);
- The CDPHE birth defect registry, a state-wide population-based system which has only been in existence since 1990 and contains data from 1990-1993 (19).
Public availability sessions were held at the Laradon Hall on Lincoln Street on December 1 andDecember 2, 1993. Approximately 50 people from the community surrounding the ASARCOGlobe Plant or who lived in the area in the past attended one-to-one meetings with ATSDRheadquarters staff. Spanish speaking staff were available for those families that only spokeSpanish. The CDPHE staff were also available during the availability meetings to answercommunity questions pertaining to the proposed medical monitoring program, off-site soilsampling and remediation, and any other question pertaining to the clean-up.
The concerns identified were:
- Has there been an increase in cancer in the area?
- Is there an increase in children and adults with asthma?
- Will the State tell people what the results of the yard sampling will be?
- Why did the City tear down the Stapleton Homes Housing Project?
- Can the chemicals of concern depress the immune system and make people more susceptible todisease such as tuberculosis?
- What recourse do people who have respiratory problems have when they start the cleanup? Will there be a telephone hotline number?
- Does the contamination from the site cause breast cancer?
- Does any of the contamination cause kidney malformations?
- Could kidney problems of my parents who lived for 15 years near the Globe plant be related to the contamination?
- Could the contamination from the ASARCO Globe plant cause respiratory problems such asdifficulty with breathing, emphysema, or asthma?
- Is cancer of the larynx or kidney in the community surrounding the Globe plant area higher than expected?
- If the soil on my property is remediated (topsoil replaced), what happens if I dig a hole for a tree or for my garden?
- Who is eligible to participate in the Medical Monitoring Program?
- What type of tests will be performed for the Medical Monitoring Program?
- Could dizziness that I have had be related to the site?
Other comments expressed by the community are the following:
- The Globeville Community Health Clinic is the only health facility and pharmacy in thenortheast part of Denver.
- Business owners located in the area are concerned whether they or their employees are eligible for the medical monitoring program.
- A citizen brought up the question of whether railroad workers who worked in the area would be eligible for the medical monitoring program.