Abstract: On the morning of June 4, 1996, Employee #1 was performing a neutralization process on nitric, hydrochloric, and sulfuric waste acids. Approximately 2 1/2, 55 gallon drums of 50 percent sodium hydroxide were added to a 1,000 gallon polypropylene tank containing 700 to 750 gallons of waste acid water. Compressed air was used to agitate the solution inside the tank. This area was delivered from a compressor through PVC pipes to the outside of the tank and into the tank to the sparger through CPVC piping. On the day of the accident, the connector between the PVC and CPVC piping kept rupturing. The plant manager and Employee #1 tried several times to make repairs. Since the connector did not hold, air could not be introduced into the bottom of the tank to initiate the agitation process. Employee #1 had used a hoe to mix the solution inside the tank several times earlier. He took samples from an outside valve on the tank to check the pH and see if the process was complete, which occurred when the pH was between 9.0 and 10, with a temperature between 150 and 190 degrees Fahrenheit. At approximately 4:00 p.m., Employee #1 had still not gotten the air working. He took an air hose from near the nickel plating line and injected air into the CPVC pipe inside the tank. He was checking the pH of the tank when it ruptured and a hot alkaline solution poured onto Employee #1. He ran to a shower near the first tin plating line to wash it off, but the water supply had been disconnected during a previous roofing job. His coworkers saw him running and washed him down with a water hose. Employee #1 sustained chemical burns and was hospitalized; he died on July 17, 1996, of complications from his original injuries. The compressors generated air into the facility at 100 psi. The air pressure in the hoses near the plating lines were between 80 and 90 psi.