This webpage is maintained by the Centers for Disease Control and Prevention (CDC). The webpage provides information and resources on Phosgene. "Phosgene is a major industrial chemical used to make plastics and pesticides. [...] At room temperature (70°F), phosgene is a poisonous gas. [...] With cooling and pressure, phosgene gas can be converted into a liquid so that it can be shipped and stored. When liquid phosgene is released, it quickly turns into a gas that stays close to the ground and spreads rapidly. [...] Phosgene gas may appear colorless or as a white to pale yellow cloud. At low concentrations, it has a pleasant odor of newly mown hay or green corn, but its odor may not be noticed by all people exposed. At high concentrations, the odor may be strong and unpleasant. [...] Phosgene itself is nonflammable (not easily ignited and burned). [...] Phosgene is also known by its military designation, 'CG.'"
Centers for Disease Control and Prevention: http://www.cdc.gov/