Abstract: On July 23, 2005, Employee #1 was a full-time, permanent employee at an automated car wash. One day earlier, Employee #1 and three other people replaced the flow electronics, all the brushes, and the soap system for the car wash. Those three people were his employer, who was also Employee #1's immediate supervisor; a friend of the employer, who would be present at the accident; and a vendor, who would also be present at the accident. Two operating air compressor systems, along with several containers of soaps, the soap system, and the controls, were in the storage room at the car wash. There were two air tanks, at least one of which, an 80-gallon tank, was in the car wash's equipment room. Both air tanks had current Cal/OSHA permits. After the work had been performed, the air tanks were operated while tests were made to the soap system. The two assistants who would be present at the accident stated that they did not notice anything out of the ordinary. Rather, they heard the air cycle on and off throughout the day. The air compressor was set to cycle on at 110 psi and off at 150 psi. On the date of the accident, the two assistants to the project and Employee #1 had plans to finish up the work they had started the previous day. Employee #1 was in the storage room cleaning up. The two assistants were walking away from the building, when they heard a tremendous explosion. The vertical 80-gallon air tank in the equipment room had exploded, killing Employee #1. He died of exsanguination (blood loss) caused by the injuries to his abdomen and pelvic region. The tank that exploded was rated for 200 psi. It was manufactured by Roy E. Hanson Jr. in 1982. It had Serial Number 42453 and Cal/OSHA Number A009641-85. The system's second air tank was manufactured by Falcon. It was of similar size to the Hanson tank. The Falcon tank was 24 inches in diameter and 44 inches tall. The serial number for this air tank was not available. The pressure relief valve from the Falcon air tank and the pressure relief valve from the compressor that had been attached to the air tank that exploded were tested by the National Board Testing Laboratory and found to be functioning properly. The regulator, safety relief valve and head of the exploded tank were not found. No corrosion was seen during a visual inspection of the remains of the air tank that exploded. The motor oil and air filter on the compressor appeared to have been changed recently.