The U.S. has destroyed the last of its declared chemical weapons stockpile, President Joe Biden said on Friday, ending a decades-long effort to eliminate the deadly weapons first used on a large scale in World War I. As part of the Chemical Weapons Convention, which was ratified by the U.S. Senate in 1997, the U.S. and other signatories are required to destroy their chemical weapons stockpile by September 30, 2023. The U.S. has been destroying its remaining stockpiles at U.S. Army Pueblo Chemica