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Superfund Program

Rocky Mountain Arsenal

Site Type: Federal Facility Final NPL City: Commerce City County: Adams ZIP Code: 80022 EPA ID: CO5210020769 SSID: 0811 Congressional District: 1

 

What's New?

Updated September 2010

EPA has issued a Notice of Deletion (NOD) for portions of the Rocky Mountain Arsenal (RMA) from the National Priorities List (NPL). The NPL is a list of the nation’s most contaminated sites, commonly referred to as Superfund sites. EPA is deleting 2,500 acres of soils, sediments, surface water and structures from the Central and Eastern Surface Areas (CES) within the RMA boundaries, called the On-Post Operable Unit. EPA is also deleting the soils, sediments, and surface water from the area just north of the RMA, called the Off-Post Operable Unit (OPS).

Cleanup at the CES and OPS is complete, and EPA and the Colorado Department of Public Health and Environment have determined that all cleanup activities needed to protect human health and the environment are complete in the deleted areas. Groundwater below both areas will remain on the NPL and is not included in this partial deletion. This is the fifth proposed deletion of a portion of land at RMA from the NPL; ninety-four percent of the land at RMA is now deleted from the NPL. Any portion of RMA that is deleted from the NPL remains eligible for cleanup response if future conditions warrant.

You may view the NOD in the Site Documents section below. A copy can also be obtained at the locations listed under the Contacts section below. Or contact Jennifer Chergo (chergo.jennifer@epa.gov), Office of Communication and Public Involvement, U.S. EPA, Region 8, 1595 Wynkoop Street, Denver, CO 80202-1129.

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Site Description

The U.S. Army established the Rocky Mountain Arsenal (RMA) in 1942 to manufacture chemical weapons. After World War II, the Army leased parts of the Arsenal to private industry. The Army and private chemical manufacturers disposed of liquid wastes in basins and trenches, which leaked and contaminated ground water. Since 1982, the Army, Shell Oil, the State of Colorado and the Environmental Protection Agency (EPA) have been involved in enforcement and legal actions to ensure the cleanup of the Arsenal.

RMA is located 10 miles northeast of downtown Denver, Colorado, adjacent to Commerce City and Brighton to the north, Montbello to the south, Denver International Airport to the east, and Commerce City to the west. Residential homes border the site to the north, south and west and residential and business development is rapidly growing in these areas.

RMA was created in 1942, at the height of World War II, when the Army purchased 17,000 acres of land to manufacture chemical weapons such as mustard gas and white phosphorus. Private industry was encouraged to lease facilities at RMA after the war to foster economic growth in the area, offset operational costs, and maintain facilities for national security. Under the lease program, Julius Hyman and Company began producing pesticides in 1946. In 1952, Shell Chemical Company acquired Julius Hyman and Company and continued to produce agricultural pesticides on-site until 1982. Common industrial and waste disposal practices used by the Army and Shell during these years resulted in the contamination of structures, soil, surface water, sediment, and groundwater.

In 1984, the Army began a systematic investigation of site contamination in accordance with the Comprehensive Environmental Response Compensation and Liability Act (CERCLA) of 1980, and as a result, the site was placed on the National Priorities List (NPL) in 1987. The NPL is a list of the nation's most hazardous sites, commonly referred to as Superfund sites. As required by CERCLA, the Army conducted a Remedial Investigation/Feasibility Study (RI/FS) to determine the nature and extent of contamination and to develop and evaluate remedial alternatives.

In the late 1980s, the Army, EPA, and Shell signed the Federal Facility Agreement (FFA), which specified the process by which decisions will be made for the cleanup of RMA and established certain cleanup goals. The FFA provided a framework under which the parties agreed to conduct Interim Response Actions (IRA) on specific contamination problems in advance of the final cleanup plan.

The FFA ultimately led to the signing of two Records of Decision (RODs). The Off-Post ROD was signed December 19, 1995 and the On-Post ROD was signed June 11, 1996. The RODs provide the framework, purpose, and overall rationale for the remediation actions that must be accomplished at the site. The Army, EPA, and the Colorado Department of Public Health and Environment (CDPHE) signed both RODs. The U.S. Fish and Wildlife Service (USFWS) and Shell concurred with the On-Post ROD.

In October 1992, the U.S. Congress enacted a bill designating approximately 16,000 acres of RMA as one of the nation's largest urban wildlife refuges. The bill allows the transfer of responsibility from the Army to the USFWS once the cleanup process is complete. To date, EPA has deleted from the NPL more than 15,000 acres of land at the Rocky Mountain Arsenal because all required cleanup activities have been completed. Of that, more than 12,000 acres have been transferred from the Department of Defense to the USFWS to become part of the National Wildlife Refuge System.

Land Deletions from the National Priorities List (Superfund Sites)

• Selected Perimeter and Surface Area Deletion: In 2004, EPA deleted approximately 5,000 acres of Rocky Mountain Arsenal land from the National Priorities List because all required cleanup activities in this area were complete. This land was then transferred from the U.S. Army to the U.S. Fish and Wildlife Service to create the Rocky Mountain Arsenal Wildlife Refuge.
• Western Tier Parcel Deletion: In 2004, EPA also deleted nearly 1,000 acres of Rocky Mountain Arsenal land from the National Priorities List because all required cleanup activities were complete in this area. This land was then transferred from the U.S. Army to Commerce City to become the Prairie Gateway development.
• Internal Parcel Deletion: In 2006, EPA deleted more than 7,000 acres of Rocky Mountain Arsenal land from the National Priorities List because all required cleanup activities were complete in this area. This land was then transferred from the U.S. Army to the U.S. Fish and Wildlife Service to augment the Rocky Mountain Arsenal National Wildlife Refuge.
• Central and Eastern Surface Areas (CES) and Off-Post Operable Units (OPS): In 2010, EPA deleted 2,500 acres of land within the RMA boundary and all of the area just north of the boundary from the National Priorities List because all required cleanup activities were complete in this area.

Following the signing of the ROD, the site has been actively undergoing 31 cleanup projects involving soil, structure, and groundwater contamination. All remediation activities are expected to be finished by 2011, depending on funding from Congress.

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Site Risk

Studies identified contamination in buildings, soil, sediments, sewers, surface water, and groundwater at RMA. Contaminants have also been detected in wildlife living in some of the more contaminated areas of the Arsenal.

Most contaminated soils are located in the central six square miles of the Arsenal. Most of the health risks posed by the site are from aldrin, dieldrin, dibromochloro-propane (DBCP), and arsenic. Aldrin is a pesticide that breaks down to dieldrin. Both chemicals are stored in the body and affect the central nervous system and liver. DBCP is also a pesticide, but it is not stored in the body. DBCP can affect the testes, kidneys, liver, respiratory system, central nervous system and blood cells. Arsenic is a naturally occurring element that can cause cancer in humans.

Media Affected	Contaminants	Source of Contamination
soil, surface water and groundwater	aldrin, dieldrin, dibromochloro-propane (DBCP), arsenic	nerve agent and pesticide manufacturing

 

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Cleanup Progress

The Army, serving as the lead agency, and Shell are implementing the remedies selected in the two Record of Decision documents for the RMA site. These include 31 projects for soils, structures, and the treatment of groundwater contaminants. The EPA, CDPHE, and Tri-County Health Department (TCHD) are conducting regulatory oversight. The Army selected Foster Wheeler Environmental Corporation (FWEC), now TetraTech ECI, in 1997 to serve as the program management contractor. FWEC selects and manages the subcontractors needed to perform the remediation work. All remediation activities are expected to be finished by 2010, depending on funding from Congress.

Numerous cleanup projects identified in the Record of Decisions have been completed. The following are a few examples:

South Plants Balance of Areas and Central Processing Area Soil Remediation Project: Contaminated soil and chemical sewers from previous manufacturing, storage, and spills of chemicals in the South Plants area were excavated and taken to the Hazardous Waste Landfill and the Basin A consolidation area. The project was completed in 2003.

Constructing the Enhanced Hazardous Waste Triple-Lined Landfill: An enhanced or triple-lined landfill was constructed south of the existing double-lined landfill and is comprised of two waste containment cells. Both cells are being constructed similar to the double lined cells with multiple layers of clay and plastic liners, but with an additional layer for enhancement. The landfill began accepting waste in 2006 and filled to capacity and closed in 2008.

Basin F Wastepile: The wastepile consisted of contaminated soil dredged from and beneath the Basin F disposal basin. The wastepile was excavated and taken to the Enhanced Triple-Lined Landfill. This project began in April 2006 and was completed in summer 2007.

Section 36 Lime Basins Slurry Wall Installation: The slurry wall is meant to isolate the underground contaminated waste from the surrounding groundwater and to prevent future migration of contaminants. Slurry wall installation began in September 2007 and was completed in 2008.

In 2005 EPA amended the RMA On-Post Record of Decision regarding Lime Basins and Basin F Principal Threat Soil Remediation. This provided for a fundamental change at Lime Basins from excavation/disposal to isolation-in-place with a slurry wall and RCRA-equivalent cover. At former Basin F, this provided for a change from solidification of principal threat soils to excavation of those soils and disposal in the Enhanced Hazardous Waste Landfill. For the Basin F exterior, this provided for the reduction in the size of Basin F, removal of some contaminated soils and other activities.

Current Cleanup Projects

 

Integrated Cover System design will provide for Resource Conservation and Recovery Act (RCRA) -equivalent covers at Basin A, Basin F, Complex Army Trenches, Lime Basins, and South Plants Central Processing Area. These RCRA-equivalent covers are designed to ensure that no precipitation migrates through the contaminated waste consolidated below. The design will provide for the construction of the 3-foot cover over a portion of South Plants, 1-foot backfill at another part of South Plants, and a 2-foot cover at a portion of Shell Disposal Trenches. Construction materials will include soil and crushed concrete currently stockpiled on the former Stapleton airport property. Construction began in June 2007 and is expected to be finished in September 2010.

The Groundwater Treatment remedy consists primarily of removal and treatment of contaminated groundwater through the continued operation of existing boundary and on-site treatment systems. There are additional areas of extraction and treatment of contaminated groundwater at contaminant sources areas.

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Community Involvement

In the 1950s, residents living north and northwest of the site began to take interest in RMA when crop damage was noticed on nearby farms. The Army began to study the groundwater flowing off the site and detected contamination. In the 1960s, the Army disposed of liquid chemical waste from the Basin F project into a 12,045-foot deep injection well after the Basin F liner began to leak. Some community members and geoscientists believed that the Army's deep injection well might have caused earthquakes in the Denver area. Although this was never proven, the Army stopped using the well in 1966 and sealed it in 1985.

In the mid 1980s, community interest peaked again with the Army's initiation of 14 Interim Remedial Actions (IRAs) for air, soil, water and structures. These response actions focused on immediate cleanup needs while the site was undergoing extensive study.

In the late 1980s, one of the site's 14 IRAs generated strong community interest, concern and involvement. The Basin F IRA involved the transfer of 4 million gallons of Basin F liquid to three 1.3 million gallon holding tanks and approximately 6.5 million gallons to a double-lined holding pond. The project also removed 600,000 cubic yards of sludge, soil, and liner material from in and under Basin F and placed it in the Basin F Wastepile. The project encountered several obstacles including heavy rainfall. The excess rainfall increased the volume of the Basin F liquid and raised the need for a second double-lined holding pond. Once the liquid was drained from the holding basin, the method used to dry the sludge so that it could be placed into the Wastepile created strong odors resulting in community concern and frustration. Several public meetings were held. Air purifiers were distributed to affected residents to alleviate odors. Local and federal government agencies studied the odors and determined there were no acute health impacts to residents.

In the early to mid 1990s, RMA had to decide how best to destroy the Basin F liquid waste being stored in holding tanks. After community outreach and input including a series of public meetings and weekend workshops, the Army, Shell and the USFWS along with EPA, CDPHE and the Tri-County Health Department decided to incinerate the liquid waste by means of the submerged quench incinerator. The incinerator began processing the Basin F liquid in 1993.

Community involvement continued throughout the 1990s. Through public meetings, publications, videos, and other communication tools, the community was encouraged to be involved in the decision making process that would ultimately lead to the ROD. The ROD outlines RMA's final environmental cleanup plans. The RMA Restoration Advisory Board (RAB) and Site Specific Advisory Board (SSAB) were comprised of community members and were formed with the purpose of informing and answering community questions about the ROD as well as listening to concerns and receiving input from the community. The Department of Defense recognizes the RAB as the official RMA citizen advisory group. The RAB is comprised of community members from the affected neighboring areas, Shell, the Army and regulatory agencies. The board meeting is held at RMA on the fourth Thursday of the month or as needed. The SSAB is comprised of community members interested in RMA. The advisory boards are still in place today but have changed focus from pre-ROD to post-ROD activities such as engineering designs and implementation of the 31 cleanup projects.

The ROD stipulated a Medical Monitoring Advisory Group (MMAG) be formed to evaluate information concerning exposure pathways from the cleanup, to identify and recommend appropriate public health actions and to communicate this information to the community. CDPHE formed the MMAG in December 1995 according to the ROD's provision and in response to citizen concerns that public health protections play a key role in RMA's cleanup program. The MMAG, comprised of community members from the affected neighboring areas, Shell, USFWS and regulatory agencies, focused on human health monitoring, environmental monitoring, emergency preparedness, and public involvement and education. The MMAG developed recommendations to monitor for any impact on community health during the environmental cleanup, and ensure information about the cleanup and the program is available to the communities. As part of the MMAG's recommendations, the group called for the creation of a Medical Monitoring Program Citizen Advisory Board (CAB). The CAB serves as a communication link to the communities, ensures the MMAG's recommendations are carried forward and makes recommendations to CDPHE on program implementation. The CAB meets two times per year or as needed.

Telephone surveys were conducted in 1998 to evaluate cleanup information and wildlife-related activities with 400 residents living in Brighton/Henderson, Commerce City and Montbello. The survey included questions about community issues among RMA neighbors, sources for local community news, knowledge of RMA's environmental cleanup and wildlife-related activities, preferences for RMA information and participation, and interest and preferences for RMA public meetings.

In 2000, another surge of public interest occurred with the recovery of 10 sarin- (nerve gas) filled bomblets. The bomblets were recovered in an old scrap yard area located in the central portion of the site. Because of RMA's proximity to neighboring communities and downtown Denver, there was high media and public interest about the bomblets and the disposal option selected. Over the course of several months, experts from the federal and state governments, including high-ranking Army officials, Colorado Governor Bill Owens, Senator Wayne Allard and Representative Diana DeGette, worked together to determine the best destruction method for the bomblets that would be protective of the community, RMA workers and the environment. A variety of community outreach tools were implemented including:

• Communicating with elected officials and the media (at times, on a daily basis)
• Distributing door-to-door information bulletins (in English and Spanish)
• Providing 5,000 flyers to local businesses for distribution
• Recording seven automated pre-recorded phone messages with critical updates that reached more than 31,000 neighbors
• Providing e-mail updates to nearly 300 residents
• Updating RMA's website daily
• Hosting five off-site public meetings (with a Spanish interpreter available for the Spanish-speaking community) to explain the destruction options and to provide a forum for community input
• Establishing a community information hotline for residents to receive more information or to talk to an RMA representative.

The Community Involvement Plan (CIP) was most recently revised in 2007. The revised CIP was based on interviews with more than 50 residents. The CIP contains information on the specific ways to keep the community informed about cleanup actions at RMA.

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Site Documents

You will need Adobe Acrobat Reader to view some of the files on this page. See EPA's PDF page to learn more.

Best way to open a very large file: right-click and save it to a folder.

Annual Update to the Five-Year Review, January 2011 (PDF, 2 pp, 47K)

Notice of Deletion, September 13, 2010

Responsiveness Summary to public comments submitted on Notice of Deletion, August 2010 (PDF, 36 pp, 3.6MB )

Ready for Reuse Determination for the Shell Property, September 2009 (PDF, 54 pp, 7.7MB )

Community Involvement Plan, January 2008 (PDF, 42 pp, 4.2MB )

Final 2005 Five-Year Review, November 2007 (PDF, 418 pp, 55MB )

Records of Decision and related Decision Documents

Note: All of the dioxin soils reports can be found in this FTP folder.

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Contacts

 

View Documents at:

Joint Administrative Records Document Facility
5650 Havana Street, Building 129, Room 2024
Commerce City, CO 80022-1748
303-289-0983
M–F, 12 p.m.–4 p.m. or by appointment

Colorado Department of Public Health and Environment
HMWMD Records Center
4300 Cherry Creek Drive South
Denver, Colorado 80246-1530
303-692-3331
888-569-1831 (toll free)
303-759-5355 FAX
M–F, 8 a.m.–Noon and 1 p.m.–5 p.m.
Appointment is required

EPA Superfund Records Center
1595 Wynkoop Street
Denver, CO 80202-1129
303-312-6473
800-227-8917 (toll free Region 8 states only)
M–F, 8:00 a.m.–4:30 p.m.
Appointment is recommended

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Photo/Video Gallery

Click on a thumbnail below to view the full size image.

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  Coyote (with prairie dog in its mouth) crossing the equipment parking area for the Integrated Cover System project, looking northwest

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  Coyote pup frolicking in the former Secondary Basins area of the Rocky Mountain Arsenal project, looking northwest

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  Thousands of migrating Canada geese in a temporary wildlife pond southwest of the former Basin F impoundment

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  American avocet in Lower Derby Lake

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  Snowy egret in Lower Derby Lake

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Links

U.S. Army Rocky Mountain Arsenal Website

CDPHE Rocky Mountain Arsenal Medical Monitoring Program

 

 

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