Inspectors from an international arms control organization have verified that the U.S. has destroyed all chemical weapons that were formerly stored at a military depot in Oregon. The Umatilla Chemical Depot, near Hermiston, underwent an inspection by the Organization for the Prohibition of Chemical Weapons in early December. The Netherlands-based group monitors compliance with the Chemical Weapons Convention, a treaty that prohibits the U.S. and 187 other member nations from producing or using chemical warfare materials. The accord also requires the elimination of all existing chemical weapons by April 2012. However, the U.S., Russia, and Libya have acknowledged that they will not meet the deadline (C&EN, Nov. 28, 2011, page 29). The Umatilla site held 220,604 containers and weapons filled with 3,717 tons of blister and nerve agents when destruction activities began in 2004. The U.S. will have eliminated 90% of its declared chemical weapons stockpile by the end of January, when it plans to complete disposal operations at the Deseret Chemical Depot in Utah. But it is expected to take until 2021 to destroy the final 10% of the arsenal.