Abstract: At approximately 3:15 p.m. on August 19, 2009, Employee #1 was repairing the cross-bracing under a semi-trailer. Employee #1 was working with a coworker, cutting iron cross-braces with a Milwaukee Table-Top Chop Saw. Approximately three feet to the north of the chop saw was a fuel oil storage tank used to fuel a "Clean Burn" heater unit attached at the ceiling. At the time of the accident, the coworker left the work area, and heard a loud explosion. He immediately returned to the area to find Employee #1's clothing smoldering, the South side of the fuel oil storage tank blown out, and oil all over the floor and surrounding equipment. The coworker removed Employee #1's smoldering clothes and instructed other employees in the area to call 911. The Pittsville Fire Department responded to the scene and began treating Employee #1 for first, second and third degree burns over his arms, legs and head. Employee #1 was transported via helicopter to the Marshfield Hospital, and later transported via ambulance to the University of Wisconsin Hospital Burn Unit. The coworker indicated that during the cutting of the cross bracing the Milwaukee Chop Saw sparks were produced which flew in all directions. At the time of the incident, the fuel oil tank had an opening port on top, with a funnel in it.