"We can honestly say that the destruction of chemical agents at Tooele Chemical Agent Disposal Facility has made the world a safer place," said Col. Mark Pomeroy.
"It's a credit to five generations of depot workers and the resolve of our nation to destroy these dangerous weapons," Pomeroy said at the depot, where the United States had stored 44 percent of its stockpile of chemical weapons since World War II.
Completion of its work means Deseret Chemical Depot beats the April 29 deadline set by a treaty among 188 nations to rid the world of chemical weapons. However, the United States will not meet the deadline because work on two other stockpiles, in Kentucky and Colorado, has not yet begun.
The chemicals were in all kinds of containers, from rockets to big metal drums, and were stored in the open air as well as in earth-covered igloos at the depot, which formerly was called and by mid-2013 will again be called Tooele Army Depot South.
For decades, before the environmental hazards were acknowledged, the Army burned thousands of chemical weapons in the open air. That stopped by the 1970s, and it took more than a decade of research to find a safe way to tackle weapons destruction.
Since the Utah plant burned its first GB nerve agent-filled rocket on Aug. 22, 1996, it has destroyed more than 1.1 million munitions containing 13,617 tons of chemical agent, said Ted Ryba, the Army's site project manager, who has worked at the depot throughout the incinerator's life.
"It gives me great joy and satisfaction to be done," said Ryba, who acknowledged mixed emotions. "We need to close it. It's bittersweet to see the fruits of your labor now have to be torn down."
He added: "This is a job that you can go home and truly say you've made the world a better place, a safer place."
Tooele Army Depot will keep a few of the buildings, but those where chemicals were handled will be demolished.
Though incineration ends this week, the 1,400 employees 1,150 for contractors and 250 for the U.S. Army will retire or lose their jobs in phases as they shut down the operation. By 2014, only a handful will remain.
Gary McCloskey, general manager of the plant for contractor URS Corp. (formerly EG&G), said that many of the workers have availed themselves of education benefits. His executive assistant, for instance, has become a registered nurse and now works one day a week in that field.
He estimated that 200 to 250 workers will take jobs at other chemical weapons destruction sites.
A large proportion of the Army employees are eligible for retirement, Pomeroy said.
While the stockpiled weapons are gone, Pomeroy acknowledged that the Army's cleanup task is not over.
Environmental work is to begin this spring to clean up the surface of two open-air "solid waste units" where the Army burned or dumped weapons and debris several decades ago.
No water contamination has been detected at those sites at the south end of the massive depot, and they pose no danger to the public, he said.
"What will happen below the surface will depend on further investigation," Pomeroy said.