In arc and gas welding, metal particles expelled during welding which do not form part of the weld are called spatter. Excessive spatter adjacent to the weld is considered to be a defect and therefore is unacceptable. Antispatter compounds used to prevent spatter build-up (on parent metals, fixtures, welding gun nozzles, contact tips, or electrode holders) may decompose during the welding process to form hazardous gaseous compounds. This study explores the theory that antispatter compounds which contain chlorinated hydrocarbons may decompose to form phosgene (carbonyl chloride). The phosgene concentration created by specific chlorinated hydrocarbons present in various antispatter compounds is investigated. The cause of one welder's illness following the use of an antispatter compound may be implied from the results of the study.