Rocky Mountain Arsenal (RMA)
39°50'N 104°50'W

Rocky Mountain Arsenal (RMA) is located in Commerce City, Colorado, approximately 10 miles northeast of downtown Denver. In 1942, at the height of World War II, the U.S. Army purchased the 17,000 acres of land on which to manufacture chemical weapons, such as mustard gas, white phosphorus and napalm.

Currently there are no chemicals or chemical weapons produced or stored at RMA and the only mission is to complete the safe, timely and cost-effective remediation and transition of the site to one of the largest, urban national wildlife refuges.

To foster economic growth in the area, offset operational costs and maintain the facilities for national security, private industry was encouraged to lease facilities at RMA after the war. 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.

North Plants

The North Plants area of the Rocky Mountain Arsenal (RMA) is a 90-acre complex consisting of 103 structures. The North Plants are located in the north central portion of RMA in Section 25. North Plants structures include: chemical manufacturing facilities, storage and warehouse buildings, chemical storage tanks, disposal systems and various support facilities.

The North Plants complex, formerly classified as a secret installation, was constructed between 1951 and 1953. It was built primarily to manufacture the chemical nerve agent GB1 (also known as Sarin) and to fill munitions with GB. The North Plants operated from 1953 to 1984, but the chemical agent manufacturing was halted in 1957. A secondary function of North Plants was to manufacture micro-gravel mines, button bombs and fill munitions with VX nerve agent.2

Beginning in the late 1950s, the North Plants became the location of demilitarization (demil) operations. The following chemical agent-filled munitions were demiliterized at the North Plants: GB agent-filled munitions, bulk GB agent stored in underground storage tanks and in ton containers, phosgene-filled bombs, munitions filled with VX nerve agent, Chemical Agent Identification Sets, small arms that had been contaminated with DDT, bulk adamsite (a riot control agent), adamsite grenades and adamsite canisters.

The U.S. Army manufactured GB between February 1953 and August 1957. Information relating to the production capacity and amounts of GB produced at the North Plants remains classified by the US Army. North Plants operations were performed under highly controlled conditions due to the dangers inherent in GB manufacturing and handling. The GB-related operations were protected by elaborate alarm systems for leak detection. Automated or remote control assembly equipment was used whenever possible. Further precautions were provided to workers in the North Plants both by protective clothing and by the complex safety procedures required for the performance of each operation. Moreover, the North Plants complex contained a clinic in Building 1710 where the workers underwent frequent and intensive medical monitoring.

After production, GB was purified through distillation and then passed through a stripping column to remove residual isopropyl alcohol and the process by-product, hydrogen chloride. The GB was then stabilized. An additional process was used from 1953 to 1955 to further distill the GB by separating the "heavy ends" or "still bottoms," thereby producing a higher quality GB nerve agent. The Army discontinued the final distillation step during the "round out" period of production which was conducted from 1955 to 1957. Finished product GB nerve agent was stored in underground tanks and in ton containers at the North Plants until it was used in munitions filling.

The Army conducted intermittent redistillation of bulk stocks of GB between 1964 and 1970. The Army also replaced the stabilizer tributylamine with diisoproplycarbodiimide (di-c-di), which allowed for the placement of GB nerve agent into aluminum casings.

The GB manufacturing processes were conducted in Building 1501 at the North Plants. Building 1501 contained three production bays. The feedstock chemicals required for GB production included: hydrofluoric acid, methylphosphonic dichloride (dichlor) and isopropyl alcohol. These chemicals were stored in tanks adjacent to Building 1501 and piped directly by remote control to the process areas. Other materials used in the GB manufacturing process included: tributylamine, the stabilizing additive; calcium chloride brine, the refrigerant; and methylene chloride, the heat transfer agent. These chemicals were also stored in nearby tanks and piped directly to the production facilities.

Liquid, mostly water containing toxic by-products from manufacturing, was piped to an 80,000-gallon disposal sump located in Building 1727. The liquid wastes contained in the sump were treated with sodium hydroxide, a caustic solution, to reduce the toxic into salts. Following treatment with caustic, the contents of the sump were discharged through a gravity-fed sewer to Basin A from 1953 to 1956 and to Basin F from late 1956 to 1976.

The filling of munitions with GB nerve agent at the North Plants began upon completion of the first manufacturing run and continued intermittently until 1969. Like the GB manufacturing operations, the filling operations were performed under closely-monitored and controlled conditions. Automated and remote mechanical filling and assembly were used wherever possible. The principal buildings used in GB bomb filling were Building 1601 (GB bomb filling and shell degreasing plant), Building 1506 (underground storage vault containing ten GB storage tanks), Building 1601 (ton container unloading and ammunition demil) and Building 1606 (bomb assembly). Munitions filled with GB at the North Plants included: bombs, bomblets, warheads, rockets and artillery shells.

Between 1955 and 1970, more than 204,000 individual, obsolete, GB agent-filled munitions were demilitarized. The GB agent contained in the munitions was either chemically neutralized with sodium hydroxide and disposed of or recovered with the intention of saving the GB agent to be used to fill other munitions. A 1968 Presidential Directive ordered the destruction of obsolete chemical weapons. As a result of these developments, a demilitarization program of all GB stocks was initiated by the Army. RMA was chosen as the site for the demil of obsolete GB and mustard, partly because of the expertise in the demil operations that had been developed by RMA personnel, and partly because of the superior facilities located at the North Plants. In October 1973, after more than four years of research and development by the task force (code named Project Eagle), the Army began an unparalleled, three-year demil program of GB agent-filled munitions and GB bulk stocks at RMA.

Four distinct GB agent-related demil operations were performed under Project Eagle:

• Demil of GB-filled cluster bombs;
• Demil of GB-filled ton containers;
• Demil of bulk GB stored in the under-ground storage tanks; and
• Demil of GB-filled rockets and bomblets.

Demil operations in the North Plants were conducted primarily in Buildings 1606 and 1611. Special automated and remote control machinery were installed in Building 1606 (for draining of cluster bombs) and in Building 1611 (for draining of missiles and bomblets). Drained munition casings were incinerated in Building 1606 and gaseous emissions were vented through coke-packed scrubbing towers adjacent to Building 1606. The munitions draining operations, like all phases of the demil operations, were subjected to extensive monitoring for detection of toxic air emissions.

GB agent that had been drained from the munitions was transferred to Building 1501 and chemically deactivated using an 18 percent aqueous asodium hydroxide. The resulting brine was piped to Building 1703 where a specially constructed spray dryer sprayed the brine, reducing it to dried salts. The dried salts were subsequently packaged in drums and stored in the 700-Series buildings in the South Plants until their removal in 1985 to an EPA-approved site. Gaseous emissions from the spray drying operations were also extensively monitored and vented to the scrubbing towers.

Wastewater from the demil operations, including decontamination water, wash-down water, and spent scrubbing solution were piped to the 1727 sump. After further neutralization with caustic and testing for residual toxic substances, the wastes were spray-dried, when practical, or otherwise discharged through gravity-fed pipes to Basin F. The Project Eagle chemical munitions demilitarization at the North Plants between October 1973 and November 1976 resulted in the demil of more than half a million gallons of GB and more than 60,000 individual munitions. Following the conclusion of Project Eagle in 1976, the North Plants complex underwent an extensive decontamination process, and many of the formerly active structures were reclassified to standby status.

Although the Army designed and used the North Plants complex primarily for the manufacture, filling and demil of GB agent-filled munitions, other Army operations were conducted at the North Plants facilities. In 1964 and 1965, a number of munitions were filled with the organophosphorus nerve agent VX in Building 1601. Bulk VX nerve agent, manufactured at the Army's plant in Newport, Indiana, and VX agent-filled munitions were stored at RMA during the 1960s. Between 1968 and 1970, the Army demilitarized relatively small quantities of VX (compared to GB operations at RMA) which had been stored in ton containers at the North Plants.

Other Army munitions demil operations were conducted between October 1965 and March 1966 when 33,538 M-78 (500 pound) phosgene/adamsite-filled bombs were demilitarized in Building 1601. Also, between October 1966 and February 1967, the Army demilitarized 194,000, 4.2-inch, phosgene-filled mortar shells in Building 1601. The final demil operations at the North Plants took place between June 1983 and June 1984 when adamsite was demilled. The 465,139 pounds of bulk adamsite and 156,587 adamsite-filled grenades and canisters were incinerated in Building 1611. In 1987, the Army transferred all remaining dichlor to the Mussel Shoals, Alabama facility, at which time the North Plants Area was entirely deactivated.

South Plants Area

The South Plants area of Rocky Mountain Arsenal (RMA) was a complete chemical manufacturing complex designed, built and used by the U.S. Army for the production of chemical weapons and conventional munitions for World War II. Beginning in 1947, portions of the South Plants were leased to private companies for the manufacture of commercial chemical products. In 1952, Shell Chemical Company (Shell) became the primary commercial manufacturer at the South Plants until 1982, producing herbicides and pesticides.

The South Plants complex is located near the center of the 27-square-mile Rocky Mountain Arsenal. The South Plants originally consisted of 295 structures, a number of which have been demolished. The manufacturing facilities were served by highway and railroad. The South Plants consisted of two major areas designated by the Army to identify buildings and to reference specific operations. They were the West Plants and East Plants.

The following buildings and operations existed within the West Plants:

• The "200 Series" buildings, site of the chlorine and the caustic complex;
• The "300 Series" buildings, location of Army munitions filling.
• The Boiler Plants, Power Plant;

The following buildings and operations existed within the East Plants:

• The "400 and 500 Series" buildings which were the location of early Army chemical agents manufacturing, incendiary munitions filling, and later the site of selected Army demilitarization operations. The "400 and 500 Series" buildings were also the location of extensive Shell pesticide operations;
• The "700 Series" buildings, also known as the Incendiary Oil Bomb (IOB) plant, which was the site of napalm mixing and various incendiary munitions filling by the Army; and
• The "Hydrazine Complex," located in the northeastern area of the South Plants, (Buildings 755-760) were the sites for blending rocket fuel.
• The "South Tank Farm" chemical storage area;

The RMA South Plants were constructed during World War II (WWII). RMA was the final U.S. Army Chemical Warfare Service (CWS) Arsenal to be built during the WWII era. Construction of RMA South Plants began on June 19, 1942 and continued for 14 months until completion on August 15, 1943. Architects, design engineers and the prime construction contractors were transferred from Huntsville, Ala. to RMA to complete the project. The transfer of these key personnel and the use of standardized designs for all structures related to production processes resulted in extremely fast and cost-effective construction of the Arsenal, including South Plants. Although the RMA facilities were built quickly, at relatively low cost and were initially intended as temporary facilities to support the United States' effort during WWII, the South Plants facility was actually a state-of-the-art chemical manufacturing facility.

CWS Arsenals (including RMA) were designed and built to be virtually self-sufficient. Electricity, steam and compressed air for RMA operations were generated at the South Plants. Also, RMA was equipped with its own sanitary sewer system, sewage treatment plant and an underground gravity feed industrial sewer system (also referred to as the chemical sewer) for the transportation of chemical wastes from the South Plants to disposal areas, which consisted primarily of solar evaporation ponds. RMA was supplied with potable water through a direct connection to the City and County of Denver water system. Industrial cooling water was supplied to RMA from Lake Cheeseman, a reservoir about 22.5 miles away.

Lewisite, a blistering agent intended for use in combat during WWII, was produced at RMA from April 1943 through November 1943. Development of an effective antidote, British Anti-Lewisite (BAL) rendered Lewisite obsolete by the end of 1943; therefore, it was never used in combat. During the Lewisite production in 1943, all Lewisite process intermediates and additives, including acetylene, thionyl chloride, arsenic trichloride, sulfur monochloride, and mercuric chloride were produced at the South Plants. Lewisite production was effected by allowing arsenic trichloride to react with acetylene in the presence of a hydrochloric acid solution of mercuric chloride. The chemical wastes resulting from Lewisite production were neutralized with lime in the 500-Series structures of the South Plants.

Levinstein Mustard (Mustard) was a chemical agent produced at the RMA South Plants from December 1942 through May 1943. Mustard production involved allowing dry ethylene to react with sulfur monochloride under controlled conditions. Mustard was produced in the 400-Series buildings at the South Plants. Commencing July 1945 and continuing through November 1946, the Army implemented a program of distilling the mustard, thereby producing a higher-quality product with superior storage and handling characteristics, termed distilled mustard. Mustard distillation was conducted in the 500-Series buildings of the South Plants which were modified subsequent to cessation of Lewisite production.

Phosgene was a chemical agent used to fill munitions at the South Plants. Although used as a chemical agent during WWI by all belligerents, phosgene was not used in combat by the U.S. Army during WWII. From January 1944 to November 1944, phosgene was purchased by the Army from commercial manufacturers, transported to RMA by railroad and used to fill munitions (100-pound bombs and 500-pound bombs). The munition-filling operations were conducted in the 300-Series buildings at the South Plants.

The preparation (by mixing or blending) and filling of incendiary munitions comprised the most extensive Army operations at the RMA South Plants during the WWII era. Five types of incendiary munitions were either filled or produced at RMA throughout WWII:

• Bombs were filled using a napalm gel which was produced in the 700-Series buildings;
• Bombs were filled in the 300-Series buildings with an incendiary mixture that was not produced at RMA;
• Cluster bombs were filled in the 300-Series buildings with an incendiary mixture that was manufactured offpost;
• Cluster bombs were filled in the 300-Series buildings with an incendiary mixture not manufactured at RMA; and
• White phosphorus, brought to RMA from offsite, was used to fill munitions igniters in the South Plants 500-Series buildings.

Additional operations conducted at the South Plants included the fireproofing and mildew protection of clothing by impregnation with chlorinated paraffin and the repair and testing of equipment such as flame throwers and grenade launchers.

After WWII, operations at the South Plants became intermittently intensive, such as during the Project Eagle demilitarization of bulk mustard, but never approached the level of activity achieved during World War II. Post WWII Army operations can be summarized as follows:

• Intermittent and selective demilitarization of mustard and cyanogen chloride munitions;
• Reconditioning of ton containers formerly used in storage of mustard, phosgene, and Lewisite;
• The filling of 105-mm shells, 4.2-inch mortar shells, and bombs with distilled mustard. Most of this activity occurred between 1953 and 1955;
• The reworking of incendiary bombs during the years 1951 and 1952;
• The periodic filling, between 1951 and 1969, of fire bomb igniters, grenades, and cups for incendiary bombs with white phosphorus;
• The manufacture of sandwich button bombs which contained a pyrotechnic mixture of potassium chlorate and red phosphorus from 1965 to 1968;
• The demilitarization and destruction of bulk mustard between 1971 and 1974 as part of Project Eagle;
• The transfer of phosgene from existing ton-containers to specifically manufactured containers that met Department of Transportation standards for over-the-road transport in order to accomplish the sale of surplus phosgene to private companies for use in commercial manufacturing processes; and
• Between 1961 and 1982, operation of the Hydrazine Blending and Storage Facility primarily consisted of blending unsym-Dimethyl hydrazine (UMDH) with equal portions of hydrazine to produce the rocket fuel known as Aerozine-50. This product was used by the U.S. Air Force to fuel Titan missiles and by NASA in the U.S. Space Program.

In 1945, when it became evident that the demand for chemical agent production and munitions filling would rapidly diminish, the U.S. Army had to consider the future of the newly constructed CWS Arsenals. Consequently, before the end of the war, the U.S. War Department received direction from Congress to lease these chemical production and storage facilities to private firms, wherever possible. As an alternative to "mothballing" CWS facilities, leasing to commercial operators was intended to provide maintenance and improvements. In addition, the leasing program would allow the facilities to remain in operating condition in the event of another national emergency, in which case the facilities would be reclaimed by the U.S. Government. As directed by the War Department, the RMA chemical manufacturing facilities at the South Plants were leased principally to the following private firms through the Corps of Engineers Real Estate Division, Omaha, Nebraska: Colorado Fuel and Iron, Julius Hyman and Company, and Shell Chemical Company.

The Colorado Fuel and Iron Corporation (CF & I), known regionally for its steel mills in Pueblo, Colorado, leased portions of the South Plants, primarily in the 400-Series buildings. Beginning in March 1947, CF & I produced chlorine and caustic soda. CF & I had planned to produce relatively large quantities of the pesticide DDT but failed both in production and in marketing of the pesticide. No significant amounts of DDT were produced at RMA. Monochlorobenzene (a precursor of DDT) was manufactured throughout 1947 before CF & I vacated RMA.

Julius Hyman and Company (Hyman) leased many of the 500-Series buildings beginning in February 1947. The facilities, designed and built by the Army for distillation of crude mustard, were modified for production of chlordane, a pesticide. Hyman manufactured chlordane from approximately 1947 to 1952. In 1950 Hyman took over the caustic soda and chlorine production facilities formerly operated by CF & I. Between 1947 - 1952, Hyman developed and manufactured the organochlorine pesticides aldrin, dieldrin and endrin.

In 1952 an adverse judgment against Hyman, resulting from a patent infringement suit brought by Velsicol Chemical Company (Julius Hyman's former employer), caused Hyman to sell its stock to Shell Chemical Company. Shell had been marketing Hyman products in the western United States since 1950. Shell operated Hyman as a separately owned subsidiary from 1952 - 1954. Shell dissolved Julius Hyman and Company in 1954, and the associated Hyman leases and operations at RMA were subsequently integrated into Shell Chemical Co. Shell referred to its operations at the South Plants as the Denver Plant. Shell Chemical Company (Shell) was by far the major commercial operator at the South Plants in terms of quantity, number of products manufactured and duration of its leases. Shell assumed Hyman's leases at RMA in 1952 and produced agricultural chemicals, including pesticides, until 1982. Shell, now Shell Oil Company, is currently working with the U.S. Army in the remediation of RMA, pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).

Shell manufacturing operations after 1953 were located primarily in the 400-Series buildings, 500-Series buildings, and at the South Tank Farm. Although the Shell-leased structures and operations were located next to the Army operations in the South Plants, the Army and Shell (lessor and lessee) manufacturing operations were entirely independent of one another. Distinguished from the manufacturing operations, the waste disposal, responses to environmental problems, and repair and maintenance of RMA facilities were often conducted in a cooperative manner between the Army and Shell. Repair and reconstruction of leased structures, roads and portions of the sewers by Shell were commonly credited through rent abatement agreements with the Army.

The only exception to the completely separate chemical manufacturing operations of the Army and Shell occurred between 1952 and 1954. On the basis of four separate contracts, Shell produced dichlor for the Army. The Army used dichlor in an intermediate process in the manufacture of GB nerve agent. The Army contracted with Shell for the manufacture of dichlor during this period because the Army dichlor production facility at Mussel Shoals, Alabama, was not yet operational by the time the Army initiated the GB manufacturing operations at the North Plants in 1953.

Shell's South Plants production of the organochlorine pesticides, developed by Hyman, involved allowing acetylene to react with intermediates such as bicycloheptadiene (BCHPD) and hexachlorocyclopentadiene (HCCPD). These operations were the foundation of Shell manufacturing operations at the South Plants. The products aldrin, dieldrin, and endrin were produced by Shell and successfully marketed worldwide until their use was banned in 1974.

Since 1982, no manufacturing, demilitarization or disposal operations relating to chemical agents have been conducted by the Army at the South Plants. Moreover, Shell ceased all manufacturing and utility operations in the South Plants by late 1982, although its leases extended to 1987.

Environmental Issues

Wastes generated during production years at RMA were disposed of using widely accepted practices of the time. Efforts to contain liquid wastes began soon after the discovery that contaminated groundwater caused crop damage north of RMA in the mid-1950s. In 1956, the Army built Basin F, an evaporation pond designed to store liquid wastes. Believed to be the first of its kind in the country, the 93-acre, asphalt-lined pond was capable of holding 243 million gallons of contaminated liquid.

The Army and Shell began a systematic investigation into the contamination problems resulting in the Army's Installation Restoration Program. Beginning in 1974, Interim Response Actions (IRA) were designed to protect off-site human health and environment from RMA pollution. Included in the 14 IRAs was the construction and operation of four boundary and on-site groundwater treatment systems responsible for treating over 1 billion gallons of groundwater each year.

In 1989, the U.S. Army and Shell Oil Company (formerly Shell Chemical Company) entered into the RMA Federal Facility Agreement (FFA) with the U.S. Environmental Protection Agency (EPA), the U.S. Department of the Interior, U.S. Fish and Wildlife Service (the Service), and the Agency for Toxic Substance and Disease Registry. As part of the FFA, the Army and Shell will implement remediation actions that comply with the Comprehensive Environmental Response, Compensation and Liability Act with all applicable regulations, laws and agreements.

In 1995, intensive public involvement helped the Army, Shell, the Service, the Colorado Department of Public Health and Environment, and the U.S. Environmental Protection Agency reach two monumental decisions. The Off-Post ROD, signed December 19, 1995, and the On-Post ROD, signed on June 11, 1996, provide the framework, the purpose and the overall rationale for the remediation actions to be accomplished at the site.

RMA will become one of the largest urban wildlife refuges in the country once remediation is complete as designated by the RMA National Wildlife Refuge Act of 1992 (Refuge Act). The Refuge Act also directs the Service to manage RMA as a unit of the National Wildlife Refuge System during remediation.