The Pueblo Chemical Agent-Destruction Pilot Plant safely destroyed the chemical weapons stockpile formerly stored at the U.S. Army Pueblo Chemical Depot, now known as the U.S. Army Chemical Materials Activity-West, near Pueblo, Colorado. The depot was responsible for safe and secure storage of the chemical weapons stockpile housed in earth-covered igloos.

Prior to destruction operations, the Pueblo chemical weapons stockpile comprised 2,613 U.S. tons of weaponized mustard agent in 105mm and 155mm projectiles and 4.2-inch mortar rounds. The Program Executive Office, Assembled Chemical Weapons Alternatives (PEO ACWA) completed stockpile destruction operations at the plant June 22, 2023, and overall July 7, 2023, in advance of the Chemical Weapons Convention treaty commitment of Sept. 30, 2023. PEO ACWA is now focused on the safe and environmentally compliant closure of the plant.

155MM PROJECTILE, M104 (HD) – M110 (HD)

Campaign Status: Complete | Campaign started: Sept. 7, 2016 / Campaign ended: Sept. 5, 2020

The M104 and M110 155mm projectiles were made of forged steel and filled with 11.7 pounds of blistering agent HD, also known as mustard. In September 2020, the PCAPP team completed the destruction of 299,554 155mm projectiles. A number of 155mm projectiles, unsuitable for processing in the main plant, were destroyed using Explosive Destruction Technology.

• The Explosive Destruction System destroyed 505 155mm projectiles.
• The main plant destroyed 298, 955 155mm projectiles, using neutralization followed by biotreatment. Metal parts were decontaminated and recycled in accordance with all environmental laws and regulations.
• The Static Detonation Chamber units destroyed 94 155mm projectiles.

105MM PROJECTILE, M60 (HD)

Campaign Status: Complete | Campaign started: Dec. 11, 2020 / Campaign ended: July 20, 2022

The M60 105mm projectiles were made of forged steel and filled with 3 pounds of mustard agent. In July 2022, the PCAPP team completed the destruction of 383,418 105mm projectiles. A number of 105mm projectiles, unsuitable for processing in the main plant, were destroyed using Explosive Destruction Technology.

• The Explosive Destruction System destroyed 304 105mm projectiles.
• The main plant destroyed 382, 944 105mm projectiles, using neutralization followed by biotreatment.
• The Static Detonation Chamber units destroyed 170 105mm projectiles.

4.2-INCH MORTAR ROUNDS, M2 (HT) – M2A1 (HD)

Campaign Status: Complete | SDC Campaign started: Feb. 19, 2022, and Main Plant Campaign started: Dec. 1, 2022 / Campaign ended: June 16, 2023

The M2 (HT) and M2A1 (HD) 4.2-inch mortar rounds were made of forged steel. The M2 round was filled with 5.2 pounds of mustard agent and the M2A1 round contained 6 pounds of mustard agent. In June 2023, the PCAPP team completed destruction of 97,106 4.2-inch mortar rounds. Explosive Destruction Technology was chosen to augment the destruction of the 4.2-inch mortar rounds. Modifications to process a portion of these rounds in the main plant were approved and that destruction began Dec. 1, 2022.

• The Explosive Destruction System destroyed 105 4.2-inch mortar rounds.

• The main plant destroyed 46,551 4.2-inch mortar rounds using neutralization followed by biotreatment.
• The Static Detonation Chamber complex destroyed 50,450 4.2-inch mortar rounds.