Abstract: At approximately 1:26 p.m., Employees #1 and #2 were working on top of a white liquor tank installing a blank into a line that had been drained for a shutdown. At the same time, Employees #3, #4, and #5 were working in the same vicinity. The liquor tank had been drained but as yet had not been opened or tested for air contaminates. As Employees #1 and #2 were installing the blank, Employee #4, a subcontractor, laid out a hole to install a ventilation fan at the top of the tank and then struck up his torch to cut into the top of the tank. At this point, a rumbling noise within the tank could be heard, followed by an explosion. Employees #1 and #2, who had been installing the blank, were blown off the tank, fell to the concrete surface 50 feet below, and died. Employee #3, a helper, was blown against a guardrail, sustaining a back injury. The two subcontractor employees, Employees #4 and #5, were caught in the blast. One went over the edge of the tank and was left hanging by the safety belt and the lanyard that he was using; he sustained a sprain and strained back. The other subcontractor employee was treated for bruising and shock. Employee #6, who was working on the ground in the vicinity of the tank, was caught in the blast as a manhole door flew open, blowing him some 40 feet across an open area.