The U.S. chemical weapons stockpile served as an important deterrent for more than half a century, but by 1985, with the rise of international concern regarding the effects of chemical warfare, Congress directed the U.S. Army to destroy the stockpile. The Program Manager for Chemical Demilitarization, or PMCD, was the organization formed by the Army to carry out this mission. At the time, the only proven chemical weapons destruction technology was incineration. As plans for the destruction of the stockpile were developed, environmental organizations, community members living near stockpile sites and government regulatory agencies began discussing other means by which the stockpile might be destroyed.

In 1996, in response to these discussions, Congress established the Assembled Chemical Weapons Assessment program, known as ACWA, under Public Law 104-208 to identify and demonstrate at least two technologies as alternatives to incineration for the destruction of assembled chemical weapons. Assembled chemical weapons refer to munitions containing chemical agent configured with fuzes, explosives and propellants.

In its initial 1996 law, and again in follow-on legislation two years later (Public Law 105-261), Congress directed that the ACWA program be conducted independently from the Army’s chemical demilitarization effort under PMCD, and further stipulated that the ACWA program manager report directly to the Office of the Secretary of Defense.

Upon ACWA’s successful demonstration of several alternative technologies from 1997 to 2000, the Department of Defense selected neutralization followed by biotreatment for destruction of the stockpile at the U.S. Army Pueblo Chemical Depot in Colorado in 2002, and neutralization followed by supercritical water oxidation in 2003 for the stockpile at the Blue Grass Army Depot in Kentucky.

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Legislation subsequently passed by Congress in 2002 (Public Law 107-248) assigned responsibility to the ACWA program manager for the safe destruction of the chemical weapons stockpile in Colorado and Kentucky, to include pilot plant construction, operation, closure and the awarding of all associated contracts, thus dual-tracking the national chemical demilitarization mission between PMCD and ACWA. PMCD would be responsible for destroying 90% of the original stockpile and ACWA, the remaining 10%. ACWA’s expanded mission resulted in a name change from “Assembled Chemical Weapons Assessment” to “Assembled Chemical Weapons Alternatives” in June 2003.

Late in 2002, ACWA awarded a task-order systems contract to the Bechtel Pueblo Team for the design, construction, systemization, pilot testing, operations and closure of the Pueblo Chemical Agent-Destruction Pilot Plant (PCAPP) at the U.S. Army Pueblo Chemical Depot in Pueblo, Colorado. A similar task-order systems contract was awarded to Bechtel Parsons Blue Grass in 2003 for the design, construction, systemization, operations and closure of the Blue Grass Chemical Agent-Destruction Pilot Plant (BGCAPP) at the Blue Grass Army Depot near Richmond, Kentucky.

In 2003, ACWA’s sister organization PMCD was redesignated U.S. Army Chemical Materials Agency or CMA. In addition to retaining its responsibility for chemical stockpile destruction at the sites other than Colorado and Kentucky, CMA was given authority over the safe and secure storage of the entire chemical weapons stockpile, to include those weapons stored in Colorado and Kentucky.

On Sept. 18, 2004, ACWA held a groundbreaking open house to celebrate Stage One construction at PCAPP. Soon thereafter, design of processing facilities and Stage One construction were temporarily suspended while the program evaluated cost reduction measures. In March 2005, design and construction of PCAPP officially restarted.

In 2006, BGCAPP broke ground on its chemical demilitarization facility, signaling the start of construction in Kentucky.

In November 2007, ACWA initiated Operation Swift Solution to safely eliminate three deteriorating steel containers and wastes associated with the management of these containers stored at the Blue Grass Army Depot. The resulting product from neutralization, called hydrolysate, was shipped from Kentucky to Veolia Environmental Services near Port Arthur, Texas.

In November 2007, ACWA was formally activated as the U.S. Army Element, Assembled Chemical Weapons Alternatives, a separate reporting activity under U.S. Army Materiel Command. Under this arrangement, ACWA received administrative and logistics support from Army Materiel Command, but the ACWA program manager continued to report directly to the Department of Defense as required by Public Law 105-261.

Effective Oct. 1, 2012, ACWA was redesignated Program Executive Office, Assembled Chemical Weapons Alternatives and administratively reassigned to the U.S. Army Acquisition Support Center. This transition was directed to raise the program’s visibility and obtain necessary support and resources. As mandated by law, the program’s direct reporting connection to the Department of Defense remains unchanged. Also in 2012, PCAPP marked the end of site construction.

In 2013, Explosive Destruction Technologies were selected to augment PCAPP and BGCAPP by destroying problematic chemical munitions stored at the depots. Problematic munitions are those that have leaked in the past and are now overpacked and projectiles whose physical condition does not easily allow for processing by the plants’ automated equipment. The Explosive Destruction System, or EDS, was the Army system selected to destroy approximately 0.2% of the total chemical weapons stockpile in Colorado. Komada LLC, a Colorado Springs-based contractor, began construction on the PCAPP EDS site in March 2014. The Static Detonation Chamber, or SDC, was the technology selected to destroy the entire mustard agent stockpile in Kentucky and reject chemical munitions in Colorado. Construction on the Blue Grass SDC began in December 2014.

In June 2014, the PEO ACWA Anniston Field Office was established to ensure that the technical expertise and experience of the staff at the former Anniston Chemical Agent Disposal Facility (ANCDF), as well as the facility’s SDC, is preserved and available to be leveraged during chemical weapons destruction in Colorado and Kentucky. ANCDF, one of seven CMA sites, finished safely eliminating the chemical weapons stockpile at the Anniston Army Depot in September 2011.

On Sept. 7, 2016, main plant operations began at PCAPP, commencing the destruction of the chemical weapons stockpile stored at the U.S. Army Pueblo Chemical Depot in Colorado. The depot originally stored more than 2,600 U.S. tons of weaponized mustard agent. The plant is utilizing neutralization followed by biotreatment as the technology to destroy mustard agent-filled munitions. Additionally, the U.S. Army’s EDS was used during two campaigns from March 2015 to December 2018 and eliminated 951 items resulting in 3.82 U.S. tons of mustard agent being destroyed. In 2018, Static Detonation Chamber technology was selected to destroy problematic mustard agent-filled munitions in Colorado.

In September 2017, the first full year of the pilot testing phase was completed at PCAPP. 253 U.S. tons of mustard agent and 42,897 155mm projectiles were destroyed at the plant. On Sept. 8, 2017, agent destruction operations were paused at PCAPP due to higher than anticipated amounts of solids being washed out of munitions and clogging agent neutralization systems.

On Feb. 15, 2018, PCAPP ordnance technicians reached a plant milestone when the last of more than 28,000 105mm projectiles went through baseline reconfiguration. On June 13, 2018, PCAPP resumed operations. By July, the BGCAPP systemization team turned over more than half of the 59 Blue Grass plant systems to operations. On Nov. 13, 2018, PCAPP staff initiated Integrated Facility Demonstrations. These demonstrations showed the plant operates as designed, which was the final step before the plant moved from pilot testing to full-scale operations in 2019.

On June 7, 2019, the BGCAPP SDC began operations. In summer 2019, PCAPP SDC site work began, with arrival of the SDC components on Aug. 6, 2019. Assembly of the SDC units began Oct. 31, 2019, and was completed in June 2020.

On Jan. 17, 2020, the BGCAPP main plant entered the operations phase with destruction of the first 8-inch projectile containing GB nerve agent. On Feb. 26, 2020, PCAPP exceeded destruction of half the agent stored at the U.S. Army Pueblo Chemical Depot. On May 11, 2020, the BGCAPP main plant destroyed all 8-inch projectiles containing GB nerve agent. This marked the completion of the first munitions campaign for the ACWA program. By June 20, 2020, PEO ACWA reached a mission milestone with the destruction of half the remaining stockpile, a combined 1,568 U.S. tons in Colorado and Kentucky. On June 23, 2020, PCAPP finished baseline reconfiguration of the 4.2-inch mortar rounds containing mustard agent. In August 2020, the decision was made to no longer use the supercritical water oxidation system (SCWO) at BGCAPP to process secondary waste, known as hydrolysate. BGCAPP would continue to use neutralization or explosive destruction technology. On Sept. 5, 2020, PCAPP completed its first munitions campaign with the destruction of nearly 300,000 155mm projectiles stored at the U.S. Army Pueblo Chemical Depot. On Dec. 11, 2020, PCAPP began its second munitions destruction campaign with the 105mm projectiles.

On Jan. 10, 2021, BGCAPP began the second main plant munitions destruction campaign with the 155mm projectiles containing VX nerve agent. This marked the first time in 12 years VX nerve agent was destroyed in the U.S. On Feb. 9, 2021, the ACWA program executive officer recommended nerve-agent hydrolysate generated at BGCAPP be treated off-site using incineration. Bechtel Parsons Blue Grass announced Veolia Environmental Services near Port Arthur, Texas, would receive and destroy the hydrolysate. On April 25, 2021, BGCAPP marked the destruction of 25% of total agent stored at the Blue Grass Army Depot. On April 26, 2021, PCAPP workers reached a milestone with the elimination of more than 50% of total munitions stored at the U.S. Army Pueblo Chemical Depot. On May 28, 2021, the BGCAPP main plant destroyed all 155mm projectiles containing VX nerve agent. This marked the completion of the second munitions campaign for BGCAPP. On July 9, 2021, the BGCAPP main plant began destroying VX nerve agent M55 rockets, the third of five campaigns to be conducted at the plant and the first time rockets have been destroyed at the facility. On Sept. 4, 2021, the Blue Grass SDC completed destruction of the mustard-agent projectiles. The SDC unit then began adaptation to destroy nerve-agent-contaminated secondary waste and was renamed the SDC 1200. A second unit, the SDC 2000, was installed to destroy nerve agent rocket components and overpacked rockets.

On Jan. 14, 2022, PEO ACWA marked 75% destruction of the original chemical agent located in Colorado and Kentucky, with the safe elimination of 2,352 U.S. tons of chemical agent. On Feb. 19, 2022, the PCAPP SDC complex began operations with the destruction of the first 4.2-inch mortar rounds in these facilities. On April 19, the BGCAPP main plant safely completed destruction of the VX nerve agent M55 rockets. This marked the total elimination of VX nerve agent in the U.S. stockpile. On July 6, 2022, the Blue Grass team destroyed the first M55 rocket containing GB nerve agent in the start of the fifth and final munitions destruction campaign in Kentucky. The GB M55 rockets represented more than 50% of the original chemical weapons stockpile safely stored at the Blue Grass Army Depot. On July 20, 2022, the Pueblo Chemical Agent-Destruction Pilot Plant team completed the destruction of more than 383,000 mustard agent-filled 105mm projectiles, the second of three campaigns undertaken since chemical weapons elimination began at PCAPP. By Sept. 9, 2022, the Blue Grass team destroyed 50% of the chemical agent originally stored at the Blue Grass Army Depot during its fifth and final destruction campaign. While destruction of the total number of munitions at the depot passed the 50% mark Aug. 1, 2022, the 50% destruction of the chemical agent contained in the weapons took a little longer (the discrepancy in those amounts is due to agent weight variances among the different munitions). On Dec. 1, Pueblo crews began using improved technology to destroy 4.2-inch mortar rounds in the main plant.

On Jan. 27, 2023, operators at the Blue Grass Chemical Agent-Destruction Pilot Plant began destroying containerized rocket warheads drained of GB nerve agent using the SDC 2000. On June 22, 2023, the last munition in the chemical weapons stockpile in Colorado was destroyed at the Pueblo Chemical Agent-Destruction Pilot Plant. On July 7, 2023, the last munition in the chemical weapons stockpile in Kentucky was destroyed at the Blue Grass Chemical Agent-Destruction Pilot Plant. This marked the completion of destruction of the United States’ declared chemical weapons stockpile. On July 14, 2023, the Kentucky Department for Environmental Protection (KDEP) granted BGCAPP a Temporary Authorization Request to begin closure activities in the main plant. The permit modification request for closure was approved by KDEP Sept. 27, 2023. On Oct. 25, 2023, the BGCAPP SDC 1200 destroyed the first containerized rocket warheads that had been previously drained of VX nerve agent in the BGCAPP main plant.

For additional program achievements and milestones visit our Program Timeline page.

For questions, visit the PEO ACWA Contact Us page to email or call the Public Affairs Office.