An explosion reported at Hoover Dam was caused by an electrical transformer that caught fire on Tuesday morning, the U.S. Bureau of Reclamation said.
Firefighters have extinguished the blaze and there were no injuries to visitors or employees, according to a bureau statement. The dam continues to produce electricity with no risk to the power grid. The cause of the fire is under investigation.
A video of what appeared to be black smoke billowing from a section of the dam was being shared on social media. Hoover Dam, which spans the Arizona-Nevada state border on the Colorado River, produces enough power for 1.3 million people in the region.