In December 2006, a journeyman pipefitter (P1) was struck in the chest by a pipe cap that he was removing from a pressurized pipe. Some leaks in an 8-inch waterline needed repair. To help find the leak locations, valves were closed off in the lines, creating sectionalized portions of the air-charged waterline. The waterline was pressurized to 80 psig. After pipe repair was completed, the air was released from the lines, except for a portion “downstream” of a closed valve, which left a section of line still pressurized to 80 psig.