This document details equipment recommendations and considerations for responder organizations when preparing for an integrated law enforcement, fire, rescue, and emergency medical service (EMS) response to an active assailant incident. It provides a list of standardized personal protective equipment (PPE) and medical supplies to facilitate consistency across responder organizations to the extent possible given individual jurisdictional and departmental protocols and restrictions. The information was compiled from documentation provided by responder agencies and technical experts in an attempt to harmonize equipment and terminology for U.S. responders.