Abstract: At approximately 2:35 p.m. on October 30, 1988, Employees #1 through #4 were attempting to ignite the #3 oxidizer's incinerator using a makeshift torch when a violent internal explosion of the #3 oxidizer's tank occurred. The employees were standing on the ground at the east side of the incinerator, which is located in the northeast section of the refinery. An eyewitness stated the 176,000 gallon capacity tank, which was approximately 1/3 filled with 530 degree asphalt, violently broke loose from its concrete foundations. The tank rose approximately 30 ft and traveled 40 ft west and collapsed along the west side of its foundation. The most severe damage occurred along the southwest section of the tank's base. The employees were sprayed with hot asphalt as the tank separated from its foundation. Employees #1, #2, and #3 died as a result of severe 3rd-degree burns over 50 percent of their bodies. Employee #4 sustained 3rd-degree burns over approximately 40 percent of his body and was transported to a Chicago, IL, hospital in critical condition. A pocket of water confined under a solid layer of asphalt at the bottom of the tank, which rapidly converted to steam, was the probable cause of the explosion.