Mustard gas incineration to start at Umatilla depot

By Annette Cary, Herald staff writer
Published: 06/04/09 1:43 am | Updated: 06/04/09 5:44 am

HERMISTON -- Work could begin this week to incinerate the last of the chemical weapons at the Umatilla Chemical Depot after the state of Oregon on Wednesday evening gave the final authorization needed for the project.

The Umatilla Chemical Agent Disposal Facility finished destroying the military nerve gas stored at the depot last November. That leaves just mustard blister agent left to be incinerated.

"This is it," said Bob Dikeman, the URS project general manager. "It is our last agent. It's our last operational campaign."

The work is expected to take one to two years, which should easily meet the April 2012 international treaty deadline.

The mustard agent is held as a liquid in 2,635 one-ton containers used for storage and shipment. Although there were far more containers of deadly VX and sarin nerve agent stored at the depot, the mustard agent made up more than half of the depot's stockpile by weight.

Since the last of the nerve agent was incinerated, work has been under way to prepare the processing plant for the mustard incineration. That included retrofitting the plant to process ton containers, bolstering systems to prevent the release into the air of mercury in some of the mustard agent and training plant workers to process the mustard agent.

Mustard agent incineration has been done in Tooele, Utah. That experience dealing with mercury in the mustard and with layers, or heels, of sludge that form at the bottom of the containers will be valuable as the Umatilla work starts, Dikeman said.

Sixty containers have been picked at random to have both their liquid and sludge heels sampled to verify that workers understand what is in the containers. In addition, 60 containers believed to have higher concentrations of metal, including mercury, will be sampled.

The first container could be moved from a storage bunker to the disposal facility as soon as today and processing could begin as soon as Friday, depending on whether any changes are required based on an earlier readiness review.

At the disposal facility, the containers will be drained and the mustard destroyed in an incinerator at 2,700 degrees. Those with sludge heels will have the solids broken up. The containers will be sent to a furnace to be decontaminated for up to 21/2 hours at 1,600 degrees.

The mustard blister agent at the depot dates to World War II. While toxic, it is less lethal than the nerve agents that were destroyed earlier. The mustard agent takes up to 24 hours to cause chemical burns or blisters to tissue it touches, including the eyes and lungs.