Abstract: A diving team began diving at 10:48 a.m. at a nuclear electric-power generation station. One of the divers, who had not eaten that morning and had not slept for more than 24 hours, entered the water and descended 19.2 meters through an access pipe. The diver was using house air with a Cuno filter, block box (filter and separator), a second Cuno filter, volume tank, air line, and Desco 61000 dive helmet. The air pressure at the volume tank was 33.2 pascals. The diver proceeded laterally 10.7 meters through a 4.9-meter-diameter pipe and ascended 6.7 meters through a 3.7-meter-diameter pipe to a butterfly valve. He then packed the valve with oakum to seal it off. About 15 minutes into the dive, the back-up diver asked the diver how he was feeling. The diver replied that he was not sure, and he terminated the dive. As he was being brought to the surface, he stated that he was in trouble, started to develop labored breathing, and lost consciousness. The back-up diver entered the access pipe to bring him up. At the surface, the employee was cut from his diving suit and cardio-pulmonary resuscitation was administered. He was transported to a hospital, where he died of asphyxia 2 days later.