The Pueblo Chemical Agent-Destruction Pilot Plant safely destroyed the chemical weapons stockpile stored at the U.S. Army Pueblo Chemical Depot (PCD), located near Pueblo, Colorado. The depot was responsible for safekeeping the chemical weapons stockpile, which was stored 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 was responsible for completing stockpile destruction operations by the Chemical Weapons Convention treaty commitment of Sept. 30, 2023. U.S. public law mandates stockpile destruction by Dec. 31, 2023.

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 2020, the PCAPP team completed the destruction of nearly 300,000 155mm projectiles, using neutralization followed by biotreatment. Metal parts were decontaminated and recycled in accordance with all environmental laws and regulations. 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 and Static Detonation Chamber units processed the remaining problematic munitions.

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 blistering agent HD, also known as mustard. On Dec. 11, 2020, the PCAPP team began destroying these weapons using neutralization followed by biotreatment. 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 and Static Detonation Chamber units processed the remaining problematic munitions.

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 and filled with 5.2 pounds of blistering agent HT, also known as mustard in the M2 round. The M2A1 round contains 6 pounds of blistering agent HD, also known as mustard. Explosive Destruction Technology was chosen to process the 4.2-inch mortar rounds. The Static Detonation Chamber units began destroying 4.2-inch mortar rounds on Feb. 19, 2022. Modifications to process a portion of these rounds in the main plant were approved. Processing began on Dec. 1, 2022. The Explosive Destruction System destroyed more than 100 4.2-inch mortar rounds and the Static Detonation Chamber destroyed more than 50,000 4.2-inch mortar rounds.