chlorides, although thionyl chloride generally gives better yields than PCl3. Safety 600 ppm is lethal in just a few minutes. 25 ppm is the US NIOSH "Immediately Dangerous to Life and Health" level 0.5 ppm is the US OSHA "permissible exposure limit" over a time-weighted average of 8 hours. 0.2 ppm is the US NIOSH "recommended exposure limit" over a time-weighted average of 8 hours. Under EU Directive 67/548/EEC, PCl3 is classified as very toxic and corrosive , and the risk phrases R14, R26/28, R35 and R48/20 are obligatory. Industrial production of phosphorus trichloride is controlled under the Chemical Weapons Convention, where it is listed in schedule 3, as it can be used to produce mustard agents. See also Phosphorus pentachloride Phosphoryl chloride Phosphorus trifluorodichloride References Inorganic phosphorus compounds Phosphorus chlorides Phosphorus(III) compounds Pulmonary agents