Abstract: On December 13, 1991, Employees #1 and #2, two maintenance employees, entered the plating tank pit of the etch line in department 65. The purpose of the entry was to change out a broken sump pump in the pit. Sulfuric acid had built up inside the pit because of a tank that had been leaking above the pit for several months. Employee #2 entered the pit first and removed the broken sump pump. Employee #1 left the area to retrieve a new pump. When Employee #1 returned, he entered the pit to give the pump to Employee #2. At this point, Employee #2 lowered the sump pump into place and plugged it in. Immediately he noticed a strong smell of acid and Employee #1 yelled that something was wrong. It was later discovered that the discharge hose from the sump pump had been leaking onto an uninsulated steam line where the acid was vaporizing. Employee #1 entered the hospital on December 18, 1991, with chemical pneumonia. He died on January 21, 1992. Employee #2 was hospitalized for 2 weeks for acid fume inhalation.