Abstract: On January 18, 1990, Employees #1 through #6 were exposed to toxic fumes. Some of the employees were wearing personal protective equipment. Employee #1 was fitting pipe at the bottom of a one million cubic foot sludge tank. He was not wearing respiratory equipment. Employee #2 was removing cement forms from a scaffold's second level, underneath workers applying cement cure. He was not wearing personal protective equipment. Employees #3 and #4 were on the scaffold's third level applying cement cure (TK 25-19). They were wearing respiratory protection. Employee #5 was stripping forms on the scaffold's second level. He was not wearing respiratory protection. Employee #6 was removing decking from a ballast ring on the scaffold's third level. He was not wearing respiratory protection. None of the employees were hospitalized.