The Pueblo plant received approval from state regulators in April to destroy 4.2-inch mortar rounds filled with HD mustard agent in the main plant.

“We received approval for Colorado Department of Public Health and Environment washout demonstration reports on April 7,” said Walton Levi, site project manager, Pueblo Chemical Agent-Destruction Pilot Plant, or PCAPP. “On April 8, the main plant began routine processing of the rounds.”

The news to move forward with the HD campaign comes shortly after the main plant completed the destruction of 4.2-inch mortar rounds filled with HT mustard agent March 31. The state approved the washout test plan for HD mortars to resolve the issue of residue lingering in the base of the mortars.

“This approval allows us to destroy as many munitions in the main plant as possible and process the last of more than 30,000 rounds in both the main plant and Static Detonation Chamber,” said Kim Jackson, plant manager, PCAPP.

Jackson said approval to destroy approximately 400 overpack munitions, which were found to be unsuitable for destruction in the main plant, is expected within the month. Once approval is received, the SDC complex will be dedicated to destroying the overpacks. In the meantime, the SDCs will continue with the destruction of HD-filled mortar rounds.

Pueblo crews first began destroying 4.2-inch mortar rounds in the main plant  Dec. 1 using an improved technology for removing mustard agent for destruction. This campaign is expected to conclude this summer, with the complete destruction of the chemical weapons stockpile in Colorado. The U.S. commitment to the Chemical Weapons Convention treaty targets stockpile destruction by Sept. 30, 2023. U.S. Public Law mandates stockpile destruction by Dec. 31, 2023.