Abstract: At approximately 11:25 p.m. on February 19, 1991, degreaser bath #150 (Department 402, Building 6) released trichloroethane vapors and the building was evacuated. Employee #1, a sheet metal worker, was overcome by the fumes and was transported to General Harbor Medical Center complaining of shortness of breath and dizziness. Upon investigation, it was determined that one of the magnetic safety valves that controlled the level of steam heat had failed to close. In addition, the force draft blower and chill water circulating the trichloroethane was inoperative. It was concluded that the lack of cooling capacity coupled with failure of the magnetic safety valve allowed the release of trichloroethane vapors.