Abstract: At approximately 4:25 p.m. on November 10, 2005, Employee #1 was filling a tank of helium at a party store. The tank was 19 inches high and 8 inches in diameter, was constructed of aluminum, and was manufactured by Kiddee. It had a CGA 580 fitting designed for helium. As he filled the tank, he heard a hissing sound so he stopped the filling process. Thinking that it was a faulty rupture disc, he removed the original disc, which was rated for 3500 psi, and replaced it with another disc rated at 3775 psi. He then used a wrench to tighten the transfill hose to the valve. When he be began fill the tank again, it exploded. He was struck by a piece of the tank approximately 10 inches long by 8 inches wide by 4 inches thick and suffered a compound fracture of his femur. He was hospitalized with his injury.