On June 14, 2002, at approximately 1243 hours, a 37-year-old male career fire fighter (the victim) drowned during the final dive of a diver training course. The victim and his partner were attempting to locate and bring an object to the surface. They were using a lifting device in zero visibility at a depth of approximately 50 feet. The victim's partner was in a kneeling position on the bottom of the lake attaching his line to the object when the victim knocked him over on his side and attempted to remove his mask. The victim's weight belt landed on top of his partner. The partner surfaced and informed the personnel in the safety boat that the victim was in trouble. The safety diver immediately entered the water and began searching for the victim. Additional divers were shuttled to the site by the safety boat to continue searching for the victim. The victim was recovered over 2 hours later using a sonar device. Advanced life support was initiated en route to a local hospital where he was pronounced dead. NIOSH investigators concluded that, to minimize the risk of similar occurrences, fire departments should: 1. ensure that equipment checks are performed before each dive and any defective equipment is repaired or replaced before the dive takes place; 2. ensure that all participants in diver training have practiced the specific evolution in a controlled environment such as a swimming pool before attempting the evolution in open water; and, 3. ensure that search-and-rescue operations establish and use reference points to conduct searches.