Abstract: Employees #1 and #2, both mechanics, were assigned to repair a bucket elevator bearing in an underground, 14 ft deep carbon pit. The pit had two access openings, but was otherwise enclosed. Employee #2 left the pit to get some tools. When he returned, he saw Employee #1 lying unconscious at the bottom of the pit near one of the openings. During the rescue effort, Employees #2 through #10 entered the pit, became dizzy, and experienced headaches. After a long period, they were able to retrieve Employee #1 from the pit using a rope and sling. Employee #1 died, and Employees #2 through #10 were hospitalized for carbon monoxide poisoning. Later, a smoldering fire in the carbon black spillage was discovered to be the source of the carbon monoxide. Causal factors contributing to this accident include: significant carbon black accumulation in the pit; lack of preparation for entering a confined space, including failure to conduct atmospheric testing, poor or no employee training, and lack of rescue equipment; and lack of ventilation in the pit.