Signs-Explosive (Placards) : Signs, called placards, placed on vehicles transporting explosives denoting the character of the cargo, or sins placed near storage areas as a warning to unauthorized personnel
United States Mine Rescue Association USMRA (membership,mine rescue and safety training resources, and mine disasters and accidents), Mine Safety and Health Quizzes, Glossary of Blasting Terms, PA,USA 2016. http: //miningquiz.com/pdf/Glossaries/Glossary_of_Blasti ng_Terms.pdf, (Blasting - Amer) {997}