Abstract: Three employees for Sahuaro Surfacing Division were in the process of repairing the float gauge on the side tank of a company dump truck called a Flowboy. They were accessing the gauge through an approximately 2-ft-diameter hatch. Employee #1 was using brake cleaner, a flammable liquid, to remove asphalt emulsion from a bolt inside the tank. He emptied two spray cans onto the bolt he was trying to remove. He decided that this process was not working, and proceeded to use a blowtorch on the bolt. The torch caused the flammable vapors from the brake cleaner to ignite, resulting in an explosion inside the tank. Employees #1, #2, and #3 were injured in the explosion. Employee #1 was admitted to the hospital for burns and Employees #2 and #3 were treated and released from the hospital. The MSDS information indicates a reasonable probability of a flammable atmosphere existing within the tank. The employee responsible for purchasing the brake cleaner had never been trained by the employer in hazard communication or to examine what he was purchasing to evaluate the hazards of what he was using.