DENVER—Cleanup work at the Rocky Mountain Arsenal interrupted by detection of a chemical weapon will resume Monday.
Federal, state and local health and environment officials approved a plan Tuesday to complete the cleanup at the Lime Basins project on the 17,000-acre arsenal 10 miles northeast of Denver.
Work was halted Oct. 31 when air monitoring detected lewisite, a chemical warfare agent developed for use in World War I and produced at the site in 1943. Officials said followup inspections and monitoring didn’t detect any more lewisite and no containers of the chemical.
Detection of the chemical led to the closure of the Rocky Mountain Arsenal National Wildlife Refuge, created on parts of the site, once a classified chemical munitions. The refuge will stay closed until cleanup at Lime Basins is completed, expected by mid-January.
The work is taking place in a restricted area of the arsenal known as a disposal area for chemical agents. A 45-foot underground vertical barrier will be installed around the perimeter of the area and a cover will be added to prevent groundwater contamination.
The Army manufactured chemical weapons at the 27-square-mile site during World War II and the 1950s. Shell Oil produced pesticides and other chemicals there until 1982. The arsenal became a Superfund site in 1987, and Congress decided to turn it into a national wildlife refuge in the 1990s.
More than 12,000 acres of the site have been removed from the Superfund site and turned into a wildlife refuge. Cleanup is expected to be finished in 2011.
The site is home to about 330 wildlife species, including deer and bald eagles.
