Abstract: At approximately 12:10 p.m. on December 1, 1993, an employer was using a large floor buffer and acetone to strip and scrub the shellac of the Mexican floor tile inside a small men's public restroom when a blast occurred and burned both his hands. The employer stated that the door was closed and the vapor was pulled up by the vent fan, which had a disconnected exhaust tube, into the water heater above the restroom. He then saw a orange and yellow flame shoot straight down from the fan, like a burst from a flame thrower, and explode as it hit the floor. The thermostat switch on the electric water heater had sparked the flame. The owner of the Hand Building Maintenance Company was injured. Neither of his 2 employees at the site was injured. The company was contracted by the complex property manager to refinish the lavatory floor, and the employer was doing the job by himself on the first day when the blast occurred. There was no employee accident-related violation; however, the employer was found in violation of 8CCR 3203(a) and 5194(e) (1) and citations were issued as general penalties.