Abstract: Employee #1, employed by a hazardous waste company at an off-site rail car cleaning operation, was cleaning a railroad tank car containing sludge with volatile organics and heavy metals (hazardous waste). A coworker, a confined space attendant/superintendent, was on the platform. Another coworker was on the ground monitoring the equipment. Employee #1 was using a Willson PD full face respirator with a five minute bottle. He lost air supply and was pulled out by the superintendent. Employee #1 suffered injury to the central nervous system due to hypoxia. The respirator's air supply was improperly operated and the coupling, which failed, had been taped.