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The Deseret Chemical Depot has reached another milestone, disposing of more than 2½ million pounds of contaminated waste created over 70 years as it stored and destroyed chemical weapons.

Called legacy waste, it included used chemical protective equipment, tools and munition-packing materials, the U.S. Army said in a statement Thursday.

The waste was generated by the depot and by the now-closed Chemical Agent Munitions Disposal System, which researched and developed chemical agents for the Army for nearly three decades.

The depot announced in January 2012 that it had destroyed the last of its chemical weapons. The United States had stored 44 percent of its stockpile of chemical weapons at the site since World War II.

The depot beat the April 29, 2012, deadline set by a treaty among 188 nations to rid the world of chemical weapons, but work on two other U.S. stockpiles, in Kentucky and Colorado, had not yet begun.

Disposing of the contaminated waste was a 3½ year project, the Army said, but it was completed nearly two years ahead of schedule, saving approximately $24 million.

After sorting, the waste was shipped off-site to treatment facilities or hazardous waste landfills; treated in the on-site autoclave before shipping; or destroyed in the Tooele Chemical Agent Disposal Facility's metal-parts furnace, the Army said.

Workers continue to close down the facility. The Tooele Army Depot will keep a few of the buildings, but those where chemicals were handled will be demolished. Completion is slated for late 2014.