Radioactivity 21 : With respect to a hazardous materials incident and to the Emergency Response Guide (ERG, Looked it up elsewhere in the source), the property of some substances to emit invisible and potentially harmful radiation
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}