Abstract: On August 25, 2005, an employee and a crew consisting of a supervisor, an operator, an operator's assistant, an emergency hoseman, was tasked to clean out a blocked pipeline system carrying 93Sulfuric Acid. All crew members donned the following chemical resistant personal protective equipment: two piece body protection, gloves, boots, face-shield, and hard hat. Lock out-Tag, line isolation, pump shut down and pressure relief procedures were followed and approved with CalPine's oversight. Line blockage was found to be in a vertical section, where the high carbon steel line was connected to stainless steel line by a threaded union. As employee applied pressure with two pipe wrenches to loosen the coupling, the pipe cracked, releasing acid under head pressure. The acid was deflected under the employee's face shield contacting him on the lower left side of his face and neck. The employee was drenched by emergency hoseman and subsequently removed to an emergency shower. The employee was taken to Kern Medical Center, where he was treated and released for second degree chemical burns. The following day examination revealed excessive swelling, and the employee was referred to Grossman Burn Center, Sherman Oaks, CA, for inpatient hospitalization. A line blockage and structural deterioration was found to be due to corrosion of piping as a result of water contamination in the acid system. Previously, this operation was performed without incident on two other acid systems. There was no visible condition identified to suspect the pipe was subject to failure. Preoperation planning and procedures were determined to be adequate. There was no evidence which suggests injuries sustained by the employee were the result of violations of Title 8 Safety Orders.