<unk>  (carbonyl chloride), chemical formula COCl2, is a colorless gas (at low temperatures, can also exist as a liquid)
Classically described as having odor of freshly cut hay
Used as a chemical weapon, and accounted for 80% of deaths from poison gas in WWI
Currently most frequently used in the industrial setting
Used in the manufacture of plastics, dyes, pharmaceuticals and pesticides
Heavier than air → stays close to ground
Used in the manufacture of plastics, dyes, pharmaceuticals and pesticides
Hydrolysis =<unk>  reacts with water in the lungs to form hydrochloric acid
Likely not clinically significant
Acylation = causes oxidative damage and depletes glutathione
Damages alveolar membrane, increases vascular permeability
Leads to noncardiogenic pulmonary edema
Likely not clinically significant
Damages alveolar membrane, increases vascular permeability
Leads to noncardiogenic pulmonary edema
Phosgene
Blister chemical agents 
Levoleucovorin
Lewisite 
Tdap
Sulfur mustard 
PALS 
Phosgene oxime 