A hazardous waste leak at the Pueblo Chemical Depot in Colorado forced the shutdown of a plant built to destroy mustard gas shells.
The shutdown occurred after a November 20 storage tank leak released 450 gallons of “hydrosolate,” which is wastewater generated when robotic machines wash the mustard gas chemicals out of shells with a lye-based compound. Three days later, officials at the depot discovered that a containment liner under other tanks was leaking rainwater.
“While neither of these events posed any danger to the workforce or surrounding communities, the resulting situations have caused plant management to indefinitely pause the disassembly of 155mm munitions and agent processing until these issues are resolved,” said project manager Gregory B. Mohrman.
The depot, east of Pueblo off U.S. 50, is home to America’s largest stockpile of chemical weapons – 780,000 mustard gas shells manufactured in the 1950s. The government ordered the destruction of the shells to comply with a 1993 treaty signed by the U.S. and 64 other nations banning the weapons and mandating the destruction of chemical weapons stockpiles by 2007.
Ground was broken for the plant in 2004, but delays have added years to an often-troubled $4.5 billion program to build and operate a factory that cuts the shells open, strips out explosives and washes away the mustard agent. Most recently, the destruction program ended up delayed by problem plumbing, which blocked the start of operations there until September. In 2015, the depot began blowing up shells that were too damaged to be run through the factory.
“The spill was associated with a seal failure on one of the agitators located on the side of a 30-day storage tank,” Mohrman said.
Depot officials said an investigation is underway to determine what caused the spill and to clean up the chemicals. Because the mustard gas mixed with neutralizing agents, officials do not believe the spilled chemicals pose a risk to the public.
First used in combat during World War I, mustard gas is a mix of chlorine, sulfur and other compounds that blisters exposed skin. If inhaled, mustard gas burns the lungs and can cause a fluid buildup that drowns victims.
The shells in Pueblo, a mix of artillery and mortar rounds, have been stored for decades in huts called igloos and have remained in what depot officials call “pristine” condition, thanks to a dry climate.
Depot officials planned to have the stockpile destroyed by 2020.