More than half a century old, the physical and chemical variability of some of the munitions being destroyed at the Pueblo Chemical Agent-Destruction Pilot Plant is causing operational challenges.

“We’re starting to see the effects of aging on the stockpile,” said Rick Holmes, Bechtel Pueblo Team project manager. “We’re having vapor leaks from munition lots that did not previously exhibit leaker tendencies. Data shows the munitions are safe in the igloo, but we’re finding they are susceptible to challenges when we take them apart.”

The variability can be classified into three categories: leakers, rejects and those with high solids content.

The plant experienced its first leaking munitions in July when at least two munitions, from a known pressurized lot, physically leaked. The leakers were identified in the Munitions Monitoring Enclosure, where agent alarms indicated the presence of mustard. No one was hurt and proper protocols were followed to safely clean up the leak and overpack the munitions, Holmes said.

“Reject munitions are those that cannot be processed with the plant’s automated system due to a variety of reasons, including corrosion, stuck bursters and inability to remove the lifting lug on 155mm rounds,” said Greg Mohrman, site project manager, PCAPP. “As of Oct. 20, 72 munitions, 46 155mm and 26 105mm projectiles, have been deemed rejects and await destruction by the project’s Explosive Destruction System.”

Higher than expected amounts of rust and other solids being washed from munitions are plugging up pipes, strainers and instruments. The presence of solids requires technicians to make frequent toxic area entries for maintenance.

“We’re learning new things about the stockpile; trying to understand it; determining the science behind it; and deciding the best way to manage it,” Holmes said.

The plant is destroying tens of thousands of munitions containing mustard agent, which have been safely stored and monitored at the U.S. Army Pueblo Chemical Depot since the early 1950s.