When Fresh-Cut Grass Means Toxic Gas

If the air suddenly smells like freshly cut hay or grass around hot metal or welding work, treat it as a chemical emergency and get away fast. The CDC says phosgene can smell like newly mown hay or green corn at low concentrations, and it warns that the gas may be produced when metals cleaned with chlorinated hydrocarbons are later welded. That is why welders are warned never to use chlorinated brake cleaners or similar solvents on parts that will be heated by an arc, torch, or intense heat. Phosgene can severely injure the lungs, and delayed symptoms can appear after exposure, so anyone who may have inhaled it needs urgent medical evaluation.

Previous Fact Next Fact