Abstract: At approximately 10:30 p.m. on January 14, 2002, Employee #1 of Catalyst Process Specialists Inc., working at the Marathon-Ashland Refinery, was inside reactor vessel #2503 to knock down mounds of catalyst that had clumped together. As the employee began chipping away at the mound, the mound collapsed on the employee, engulfing him in the catalyst. Employee #1was engulfed by the catalyst. During his struggle to get free of the collapsing catalyst, more and more engulfed him, and eventually, the face seal of the helmet used by the employee broke allowing for the fresh air to be released into the catalyst and for catalyst to enter the mask. Supplied air was released from the helmet into the catalyst, causing it to ignite. Employee #1 was killed as a result of chemical burns.