What is Phosgene gas and how to protect yourself from it

Phosgene gas/COCl2 is an incredibly toxic gas first used as a chemical weapon in World War One, Phosgene is used primarily as an industrial chemical however it was realised that due to it’s high toxicity it would be useful as a chemical weapon. Phosgene is mostly colourless and has a faint odour of freshly mown grass or hay, however if you can detect the smell you have already inhaled a lethal dose of phosgene, phosgene destroys the lining of the lungs but death can take 24-48 hours after exposure. Around 8