HERMISTON -- The emission stacks of the plant once used to incinerate chemical weapons at the Umatilla Chemical Depot were pulled to the ground Friday morning.
That wrapped up demolition of the main facility at the Umatilla Chemical Agent Disposal Facility, three months after Northwest Demolition of Tigard, Ore., began work.
Next the plant site will be excavated several feet down and samples collected to ensure the site is clean. In addition, some ancillary tanks for brine solution and piping adjacent to the Munitions Demilitarization Building must be removed.
That work should be completed in early 2014, leaving paperwork and additional sampling required to close out the facility's permit with the state of Oregon, said spokesman Hal McCune.
URS, which holds the contract to build, operate and decommission the plant, employed as many as 830 people, of whom commuted from the Tri-Cities, when the plant was operating.
That has dropped to 149 employees now and more workers will lose their jobs in February after demolition is complete, leaving about 80 people employed. Work to close out the permit is expected to continue through 2014.
The stacks that came down Friday were used for filtered emissions from the plant's furnaces and its ventilation system as the plant destroyed chemical weapons starting in fall 2004.
A torch was used to cut a section of the base of the stacks and then they were pulled to the ground with cables attached to excavators, McCune said.
A maintenance building and office and storage space that supported the incineration plant will not be demolished and will be made available to Umatilla County government, port districts and private businesses.
During the seven years the plant operated, it processed 260,604 munitions and about 3,720 tons of chemical agent, including nerve gas.
The last of the depot's stockpile was destroyed about six months before the deadline in the Chemical Weapons Convention international treaty.
-- Annette Cary: 582-1533; email@example.com; Twitter: @HanfordNews