Abstract: At approximately 6 p.m. on September 17, 1998, an employee received chemical burns to various parts of his body. The employee is a waste water treatment technician on the 6 p.m. to 6 a.m. shift. At the beginning of his shift, the employee began his daily waste treatment systems inspection. At the waste treatment area for building 1220 (outdoors), the employee observed overflowing and flooding from the clearwell (a 500-gallon reservoir). A drain pipe leading from the clearwell to the acid neutralization system was determined to be clogged. To clear the obstruction, the employee added approximately 200 ml of concentrated (95-98) percent sulfuric acid, from a 2.5-liter glass bottle, to a vertical 2-in. pipe extending up from the clogged (horizontal) drain pipe to a height of approximately 15 inches above the top lip of the flooding clearwell. The employee obtained the acid bottle from the chemical stock room in building 1055. Upon addition, a mixing reaction immediately occurred in the interior of the vertical pipe, and liquid was ejected out of the pipe onto the employee's face, arms and legs. The employee was wearing safety eyewear with side splash protection, latex gloves, a cotton short-sleeved shirt and cotton trousers. The employee immediately flushed his eyes and then showered his body with the eyewash and shower station located approximately 25 yards from the clearwell. The employee received first-and-second-degree burns to his face, left ear, right arm and leg, and skin discoloration (temporary) to 25 percent of his face. The employee was not adequately protected for the exposure with engineering controls or suitable face and body protection.