Abstract: On April 18, 1995, Employee #1, of Image Labs, was working on a filling operation when the electronic liquid filling machine that she was tending developed a fault. The lid of a tank approximately 3 ft above her head was ejected and struck her head. The tank was full of liquid under 10 psi pressure and was fitted with a pressure relief value set at 25 psi. A clamp that was clamped by a nut and bolt secured the lid on the tank. The brass nut failed, causing the lid to fly off. Employee #1 was taken to St. John's Hospital, Oxnard, CA, where she was treated and released. No citation was issued. The electronic liquid filling machine was maintained to manufacturer's specifications without modifications. Modification to the tank has been made, a safety chain now secures the lid and the nut is now stainless steel.