Demolition of Demilitarization Building Completed

The massive building that housed the equipment and furnaces that destroyed the Umatilla Chemical Depot’s chemical weapons stockpile has been demolished, and the last remnants of the plant’s pollution abatement systems came down last Friday morning.

Northwest Demolition out of Tigard, pulled down the two stacks that were connected to the pollution abatement systems of the plant. The stacks were the last plant structures standing since the remaining walls of the Munitions Demilitarization Building were knocked down Wednesday.

Northwest Demolition was able to demolish the building in three months, even though the thick walls were heavily reinforced with extra rebar. It started demolition on Aug. 15.

The contractor will now excavate the plant site several feet down, which will be followed by sampling to conclusively show the site is clean. Some piping and equipment related to the plant also still must come out. All the areas of the plant where chemical munitions, chemical agent or plant waste streams were handled or processed have to be demolished in accordance with the project’s operating permit with the state. The entire demolition process is expected to be completed by early next year.

The support buildings and offices at the plant site are being preserved for potential use by the Depot Reuse Authority, which is in charge of how the depot land will be used in the future.

The Umatilla Chemical Agent Disposal Facility processed 220,604 munitions and about 3,720 tons of agent between the fall of 2004 and fall of 2011. It destroyed the depot’s stockpile about six months before the international treaty deadline. The project has been in closure operations since, and the workforce has been gradually reduced from more than 800 workers to 149. Another 60 employees will be released in February after demolition is complete. Work on closing out the permit will continue through next year.