(Reuters) - Six workers were injured in an explosion at a Washington state dam on Thursday, officials said, though the structural integrity of the dam was not threatened.
The explosion occurred around 4:30 p.m. PT at the Priest Rapids Dam on the Columbia River, about 160 miles southeast of Seattle, said Kyle Foreman of the Grant County Sheriff's Office.
The blast stemmed from a malfunction of electrical equipment at the hydroelectric dam, said Thomas Stredwick, a spokesman for the Grant County Public Utility District.
The six injured workers were transported to area hospitals by ground and air ambulance and their families have been notified, Stredwick said. The extent of their injuries was not yet known.
Two of the patients were being sent to Harborview Medical Center in Seattle, the medical facility said.
The cause of the explosion was being investigated and there was no serious structural damage to the facility.
The Priest Rapids Dam is one of two large hydroelectric power plants on the Columbia River, with the other, the Wanapum Dam, located just a short distance upstream, the Grant County Public Utility District said on its website.
(Reporting by Curtis Skinner in San Francisco and Victoria Cavaliere in Los Angeles; Editing by Eric Beech and Himani Sarkar)