"Carbonyl dichloride"@en . . . "Phosgene"@en . "Phosgene is the chemical compound with the formula COCl2. This colorless gas gained infamy as a chemical weapon during World War I where it was responsible for about 85% of the 100,000 deaths caused by chemical weapons. It is also a valued industrial reagent and building block in synthesis of pharmaceuticals and other organic compounds. In low concentrations, its odor resembles freshly cut hay or grass."@en . . . . .