Abstract: Employee #1, a commercial diver, was inspecting and filming the inside of a large commercial drinking water storage tank. After making one dive with a hand-held video camera, he returned to the surface and asked the attendant at the manway to get him a 35mm still camera. While he was waiting, he unhooked his tether line; after receiving the camera, he went underwater without reattaching it. Approximately 5 minutes later, the attendant heard a splash and saw Employee #1 floating face up on the surface. He called for help, and the tender attempted to throw him a line, but he couldn't grasp it. Emergency services was alerted, and ultimately the tank was drained to remove Employee #1. He was pronounced dead at the scene. At the time this report was written, the cause of death had not yet been determined.