A spokesman for a Washington nuclear power plant has said that a small amount of hydrogen gas trapped in a pipe ignited in a brief, six-inch flame Thursday when workers cut into the pipe, the Associated Press reported on Friday.

Columbia Generating Station declared an unusual event, evacuated plant areas near the pipe for about 90 minutes, and notified the Nuclear Regulatory Commission.

No one was injured and no equipment was damaged in the puff, which Energy Northwest spokesman Mike Paoli said lasted less than a second. Still, the Columbia Generating Station declared an unusual event and temporarily evacuated the immediate area.

Officials notified the Nuclear Regulatory Commission.

The pipe is located in the plant's main turbine building, which is a non-nuclear area, Paoli told Associated Press.

There's no association whatsoever with the reactor building or radiation, he is quoted as adding.

Energy Northwest is a joint operating agency including 28 public power member utilities. It operates a mix of hydroelectric, solar and wind energy projects as well as the nuclear plant.