Five days after beginning destruction of mustard-filled mortars as part of ongoing chemical agent operations at Deseret Chemical Depot, officials called off the campaign Monday as a result of elevated levels of mercury detected in the cartridges.

“We didn’t anticipate the levels of mercury would be an issue,” said DCD spokeswoman Alaine Grieser. “When we got started, we discovered that our assumptions were wrong.”

Mercury emissions, while permitted at certain levels, pose a threat to the environment. As a result, workers transported the mortars back to storage until they can be processed using a new filtration system, which is currently under construction and expected to be finished this fall, according to Grieser. The sulfur-impregnated filter will serve to capture mercury compounds before the exhaust from the incineration process is released into the atmosphere.

The mortars will join nearly 1,000 other mustard-filled bulk containers sampled last year that also possess elevated mercury levels.

“We are just going to treat them all the same,” Grieser said, adding that change will not hamper the depot’s efforts to meet treaty-designated deadlines.

“Doing those mortars now would have helped us with early closure with parts and pieces in the plant,” she said. “From what I have been told, this is not going to affect our agent destruction schedule.”

Mustard agent was first used during World War I. If exposed, a person can suffer from blisters of the skin, inflammation of the eyes, nose, throat, trachea, bronchi, and lung tissue. Doses approaching the lethal level can result in injury to the bone marrow, lymph nodes, and spleen. The agent has also been deemed a carcinogen.

Beyond mustard destruction operations, the depot is also devising a plan to destroy small amounts of GA nerve agent and Lewisite blister agent. Last September, officials initiated an environmental assessment process on a proposal to build a new small-scale liquid incinerator, which features a special exhaust system designed to handle the arsenic associated with Lewisite. In early March, the final finding of “no significant impact” gave officials the green light to delve deeper into the process.

“Now we can go further into the design phase and applying for permits,” Grieser said, adding that construction is anticipated to begin in early 2010.

Jamie Belnap: jamieb@tooeletranscript.com