Abstract: Employee #1 was using 1,1,1-trichloroethane to clean oil sludge in a 46 in. by 46 in. by 46 in. lubricating oil sump of a powerhouse turbine generator. He was found collapsed in the sump, but was conscious 10 minutes later and refused assistance. Employee #1 and his coworkers were unaware of the hazards associated with toxic vapors of high density and high pressure in an open low area such as an oil sump. There was no confined space entry procedure or program. Lack of hazard communication training and unsafe work practices such as cleaning the bottom of the sump on hands and knees, wringing solvent soaked rags into the sump drain, and placing open cans of solvent in the bottom of the sump, contributed to the accident.