Course of events During routine inspection of the chain locker with chain, one member of an inspection team fainted during the inspection and died shortly after. A second member fainted during the rescue operation, but recovered. One member had entered the chain locker through a manhole on deck and had started the inspection approximately 2 metres below the deck. The chain locker is of the rectangular type and the chain rests on a perforated bottom above the bottom of the locker, see enclosed figure. The other two members of the team remained on deck. After a few minutes the person in the chain locker was observed lying apparently unconscious in a corner. A second member of the team then immediately went down to rescue and sent the third member of the team to call for assistance. During this first attempt of rescue also the second member of the team fainted. First aid was given as soon as the two men were brought out of the chain locker and on the way to hospital. The life of the member who first entered the chain locker could, however, not be saved. Extent of damage One person killed. Probable cause The immediate cause of this tragic accident was lack of oxygen in the chain locker, probably caused by the on-going corrosion process over time and the stagnant atmosphere in the chain locker. The manhole for the chain locker had been opened some hours prior to the inspection but the cover had been put loosely on again in order to prevent anyone to stumble into the locker. The chain pipes leading to the locker had been made temporarily tight by cement in order to keep seawater out. The anchor had apparently not been used the last 4-5 years. The locker appeared to be clean and painted and the chain was found without extensive corrosion. However, some corrosion was found at the bottom of the chain locker, including some remaining water. The oxygen content of the atmosphere in the chain locker was measured shortly