For over a decade the Army has been carrying out a program aimed at the destruction of accumulated chemical weapons stored at several sites. While destruction by incineration has been successful, several incidents -- called chemical events -- occurred during the disposal process or decontamination activities that raised some public concerns about the safety of operations of three third generation incineration facilities. As a result, the Congress asked the NRC to investigate whether the incidents provide information useful to help ensure safe operation of the future sites. This book presents an analysis of causes of and responses to past chemical events, implications of such events for ongoing and future demilitarization activities, and recommendations for preparing for future events.