Abstract: At 9:30 a.m. on June 10, 2003, Employee #2 requested help to unclog the strainer on Tank Number 1 on the pickling line. Employee #1 met Employee #2 at the tank. Employee #1 said he turned off the pump to stop liquid from being pumped through the system. Employee #1 said that he asked Employee #2 if all of the valves were closed, which meant that Employee #2 had drained, flushed, and blocked the system. Employee #1 thought Employee #2 answered yes. Employee #1 said that they were having trouble removing the sight glass to access the strainer. Employee #1 requested assistance from another worker, Employee #3. Employee #3 assisted and they removed the sight glass. Employee #3 discovered that the pump was not off as it should have been. Energy control procedures were not performed. A negative pressure had built up in the system. That is why it was so difficult to remove the sight glass. At that time Employee #2 proceeded to turn the pump off. The solution inside of the system reversed, due to loss of pressure when the pump was turned off, and sprayed out onto Employee #1 and Employee #2. Employee #2 immediately began to hose himself off and proceeded to the shower. Employee #1 did not shower immediately. Instead, he began to try and contain the spill. Employee #1 closed off valves and pumps. Employee #1 said that he did not realize how badly he was burned until about 30 minutes after the acid solution sprayed out of the tank onto his body. Employee #1 was hospitalized with acid burns.