The Army has again reduced the estimated number of defective chemical weapons stored in Colorado that have to be destroyed with explosives.
Officials said Monday about 1,300 shells will be torn open with explosives inside a closed chamber at the Pueblo Chemical Depot. The mustard agent will be drained and chemically neutralized.
Officials once estimated as many as 40,000 shells would be destroyed that way. The number shrank as they refined their assessment.
About 780,000 shells containing 2,600 tons of mustard agent are stored at the depot. They're being destroyed under an international treaty.
Most will be dismantled by robotic technology, and water and bacteria will be used to neutralize the mustard agent.
Leaking shells and others deemed unsuitable for that process will go through the explosive technology.