A gas mask that consists of a half-mask facepiece or mouthpiece, a canister, and associated connections, and that is designed for use during escape-only from hazardous atmospheres
Tom May, CEM, Steve Davis, Larrie Wright, All Hands Community, Glossary of Terms and Definitions (in the fields of Emergency Management, Business Continuity and related service areas), 3rd Ed, USA 2005. http://www.macogonline.org/archive/homeland/emerge ncy_glossary.pdf, (Emr Mgt, Biz Cont and related srvc areas - Brit) {482}