Superfund Information Systems: Site Profile

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The Vasquez Boulevard & Interstate 70 (VB/I-70) Superfund site is located in northeast Denver, Colorado. The site includes two commercial/industrial areas as well as residential properties in all or part of the following neighborhoods: Cole, Clayton, Swansea/Elyria, southwest Globeville and northern Curtis Park.

Map of the site (PDF) (1 pg, 3.1 MB, About PDF)

Historically, the area was a major smelting center for the Rocky Mountain West. Two smelting plants—Omaha & Grant and Argo—operated at the site for varying lengths of time, beginning as early as the 1870s, refining gold, silver, copper, lead and zinc. As a result, heavy metals were deposited in area soils at levels that, in some cases, posed a health risk to people living there. Groundwater was also impacted at the former smelter locations.

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What Is the Current Site Status?

In 2009, EPA conducted a standard five-year review (PDF) (25 pp, 1.4 MB, About PDF) of the remedy at VB/I-70. The review determined that the remedy for the residential soils (OU1) was not protective of human health because there were still approximately 180 properties where EPA was never able to gain access from the property owner to either sample or clean up. The five-year review report recommended implementing institutional controls to protect current and future residents from the possible or known soil contamination at those properties. As a result, in 2012–2014, EPA embarked on a renewed outreach effort to all of the remaining properties, giving the property owners another chance to have their property sampled and cleaned up if necessary. EPA’s outreach efforts resulted in about 100 more properties sampled. Twenty-five of those properties required cleanup, which occurred in 2013 and 2014.

In June 2014, EPA placed Notices of Environmental Conditions in the property files of approximately 65 properties where, despite all efforts, EPA was not able to gain access to from the property owners. The notices are filed at the City and County of Denver Clerk and Recorder’s office. Residents and owners of these properties will also receive annual mailings alerting them to the potential or known contamination issue and providing them with simple steps to avoid exposure.

Omaha & Grant Smelter (OU2): Environmental investigations continue at the former Omaha & Grant Smelter location.

Argo Smelter (OU3): Environmental investigations continue at the former Argo Smelter location.

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EPA’s Involvement at the Site

In January 1999, EPA listed the VB/I-70 site on the EPA National Priorities List. Sites on the National Priorities List are commonly referred to as Superfund sites because they are eligible for Superfund resources, environmental investigation and cleanup processes, and public participation opportunities. EPA is the lead agency for Superfund activities at the VB/I-70 Superfund site, working cooperatively with the support agency, the Colorado Department of Public Health and the Environment.

EPA divided the VB/I-70 site into three operable units to better manage the project. Operable Unit 1 (OU1) includes residential soils in more than 4,500 yards in all or part of six neighborhoods: Cole, Clayton, Swansea/Elyria, southwest Globeville and a small section of northern Curtis Park. Operable Unit 2 (OU2) includes the location of the former Omaha & Grant Smelter, which is today the location of the Denver Coliseum and surrounding businesses. Operable Unit 3 (OU3) includes the location of the former Argo Smelter, which is today the commercial area adjacent to and northwest of the Interstate 70 and Interstate 25 interchange.

Residential Soils (OU1): In 1998, EPA and the Colorado Department of Public Health and Environment began investigating residential yards to determine if heavy metal residues from past smelting operations posed a potential threat to the health of residents. The investigation showed elevated lead and arsenic concentrations in some yards. A large-scale residential soils investigation ensued.

In May 2002, EPA released a proposed plan outlining its preferred cleanup option. Due to extensive public comments, EPA lowered its initial proposed soil concentration cleanup levels. A  Record of Decision (ROD) (PDF) (87 pp, 5 MB, About PDF) detailing EPA's final cleanup decision was issued on September 25, 2003, in which EPA announced it would cleanup yards with lead concentrations of 400 ppm (parts per million) or above and/or arsenic concentrations of 70 ppm or above. The ROD included a Responsiveness Summary of the public comments received.

From 2003 through 2006, EPA carried out a vast residential soils sampling and cleanup project. The majority of yards sampled had results below EPA’s levels of concern and did not require any further action. However, about 1 in 5 yards sampled did require further action due to elevated levels of lead and/or arsenic. At these properties, EPA removed contaminated soil, replaced the yard with clean soil, and re-landscaped. In all, EPA sampled more than 4,500 properties, and removed and replaced soil at about 800 of those yards that needed it. During the process, EPA removed more than 91,000 cubic yards of contaminated soil.

In addition to soil sampling, removal, replacement and relandscaping, EPA provided for a lead paint assessment and abatement program to ensure that lead paint peeling from the exterior of a home did not recontaminate soil. EPA also sponsored a community-based Community Health Program. The Community Health Program helped to raise awareness in the community about lead and arsenic hazards. The Community Health Program was a unique program designed by local, federal and state government representatives and committed community leaders. The city of Denver administered the program, which included door-to-door visits from community members trained to become Community Health Workers and provided education to area residents on the hazards of lead, arsenic and a range of other environmentally-related topics. The program provided opportunities for parents to have their children tested for lead or arsenic exposure. The Community Health Program concluded in 2008.

Omaha & Grant Smelter (OU2): Operable Unit 2 (OU2) is in an historic industrial area of Denver. OU2 encompasses the approximately 50 acres of the original Omaha & Grant Smelter facility and includes the Denver Coliseum, a portion of the Globeville Landing Park, and surrounding businesses. OU2 is generally bounded by I-70 on the north, the South Platte River on the west, Brighton Boulevard on the east, and the southern boundaries of the Globeville Landing Park and the Pepsi Bottling Company property on the south.

The Omaha & Grant Smelter facility operated from 1882 until 1903. A lead smelting process was employed at the facility to produce gold, silver, copper, and lead. After closure in 1903, the smelter buildings were subsequently demolished. Prior to constructing the Denver Coliseum and associated parking lot in the early 1950s, portions of the site were used as a landfill for disposal of construction debris and municipal solid wastes.

In 1992, the Colorado Department of Public Health and Environment began assessing for environmental contamination at the former Omaha & Grant Smelter location. In 2000, EPA initiated a separate investigation of the smelter facilities. The City and County of Denver, with EPA and state oversight, later conducted a thorough remedial investigation that assessed potential heavy metals contamination in the soils, groundwater, surface water, and sediments. EPA conducted additional groundwater sampling in 2012 and 2013.

Currently, EPA is working with the City and County of Denver (CCOD) on CCOD’s plans to upgrade the stormwater management infrastructure to meet a 100-year flood capacity. EPA is involved with the portion of the stormwater management infrastructure that traverses OU2 in the vicinity of the Denver Coliseum. This upgrade will require the excavation of potentially contaminated materials. Following EPA protocol, CCOD will conduct the work while ensuring that protective measures are taken to address any potential releases of, or worker exposure to, hazardous substances.

Argo Smelter (OU3): In 1992 the Colorado Department of Public Health and Environment began assessing for environmental contamination at the former Argo smelter. OU3 is bordered by 48th Avenue, Interstate 70, Lincoln Street, and Huron Street, at the intersection of Interstate 70 and Interstate 25. At issue is whether smelter generated wastes, primarily heavy metals, buried at the site pose a risk to future construction workers or groundwater. The majority of the OU3 area is paved and has been extensively redeveloped since the smelter stopped operating. EPA conducted a remedial investigation, developed a feasibility study, and presented a proposed plan with a preferred cleanup alternative to the public for review in 2007. However, groundwater data proved to be insufficient, which required EPA to conduct additional groundwater sampling.

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