The US used mustard gas in WWI. Chemical weapons are thought have been responsible for killing at least 100,000. Subsequent use was banned by the Geneva Convention. Nearly 800,000 munitions containing mustard gas were stored at the Pueblo, CO Army Chemical Depot. Workers there started to destroy the munitions in 2016 and completed neutralizing the entire stockpile in June. The location and disposal process was always a concern to civic leaders. In Kentucky, the local community succeeded in stopping the building of an incineration facility to dispose of 520 tons of chemical agent. The Army responded by burning the munitions at remote sites on Johnson Atoll in the Pacific, or in the desert of Utah. A Kentucky disposal facility using a dilution process was eventually built in 2015 that began operating in 2019. The Colorado and Kentucky sites were the last where chemical weapons were stockpiled and destroyed. Other sites included Arkansas, Alabama and Oregon.
Only three countries have not signed the chemical weapons treaty--Egypt, Sudan and North Korea. Israel has signed, but has not ratified the treaty. There is some concern among US officials that Russia and Syria still possess undeclared chemical weapons. Next on the disarmament agenda: nuclear weapons. The vice-chair of the Arms Control Association declared,“It shows that countries can really ban a weapon of mass destruction. If they want to do it, it just takes the political will, and it takes a good verification system.”