GRANT CO., Wash. – A mechanic working on the Wanapum Dam slipped and hit his head officials said Tuesday morning.

The unidentified hydro mechanic was airlifted to a nearby hospital in stable and responsive condition.

“He was performing maintenance inside a dewatered draft tube, which is the exit for water that has passed through the turbine, when he slipped and hit his head,” Grant PUD officials wrote in a Facebook post.

“There wasn’t water in there because they were doing routine maintenance,” Chuck Allen, the Grant PUD public information officer said. “He slipped and hit the edge. He was upright and fell and hit his head.”

Allen said they would be conducting an investigation into what happened Tuesday morning. He said the area of the incident was not in service at the time due to the maintenance being done, and would not impact the daily function of the dam.