Formally known as the "Convention on the Prohibition of the Development, Production, Stockpiling, and Use of Chemical Weapons and on Their Destruction," this treaty requires each state party to destroy all the chemical weapons (CW) and CW production facilities it possesses or that are located in any place under its jurisdiction or control, as well any CW it abandoned on the territory of another state. The CWC was opened for signature on January 13, 1993, and entered into force on April 29, 1997. As of August 2001, there were 143 parties to the CWC; in addition, 23 states have signed but not ratified the CWC.