This analysis describes the frequency and type of injuries among responders to hazardous materials releases. Data were analyzed from states that participated in the Hazardous Substances Emergency Events Surveillance system maintained by the Agency for Toxic Substances and Disease Registry from 1996 through 1998. A total of 348 responders were injured in 126 (0.7%) of 16,986 reported events. Firefighters and police officers were most often injured. Respiratory irritation and nausea were the most commonly reported injuries, and no injuries resulted in death. Almost half of the responder victims wore firefighter turn-out gear, and about a third had received hazardous materials training. Chemicals frequently released during these events were in the category "other substances not otherwise specified" and "acids." Training, education, planning, and coordination are needed to effectively respond to hazardous substances emergency events.