Abstract: Employee #1 was working in the paper machine low density area at International Paper Company. He had been assigned to change out a pig-tail on an empty one ton sulfur dioxide cylinder and to reconnect it to a full one. Employee #1 was found collapsed and not breathing at the base of a cement column approximately 117 ft from the sulfur dioxide cylinder. He was not wearing any respiratory protection. Employee #1 had a history of asthma and the company doctor had him on restricted respirator use, although the employee's immediate foreman had no knowledge of this. The autopsy report concluded that Employee #1 died naturally as a result of asthma. It also indicated that the employee may have been exposed to toxic gases or chemicals. No JSA or safe work practices were in place for this task. Samples analyzed by CSHO identified overexposure to sulfur dioxide (8.4 ppm STEL). The header valves on the sulfur dioxide system were extremely worn and the pig-tails showed crimping. Back pressure from the system allowed the pig-tails to leak sulfur dioxide each time they were removed. Although there was no evidence of sulfur dioxide in Employee #1's tissue, it is a very effervescent gas and, in low concentrations, is known to induce asthma attacks in susceptible individuals.