Fatal chemical pneumonia from 1,1,2,3,3-pentafluoro-3-chloropropene in an unmarked gas tank.

Fatal chemical pneumonia occurred in a worker following exposure to an unidentified gas in a salvaged cylinder. Inspection of the tank revealed a scrawled chemical formula for 1,1,2,3,3-pentafluoro-3-chloropropene, a suspected pulmonary irritant. The report underscores the potential hazards which salvaged cylinders pose to individuals who use or refill them. The population at risk includes scuba divers, emergency rescue personnel, and workers in the compressed gas industry.