Video shared by a tourist at the Hoover Dam showed a fire and black smoke after what the woman claimed to be an explosion at the hydroelectric plant.

A large explosion rocked the Hoover Dam during a tour of the facility early Tuesday, dramatic video shows.

A blown transformer was determined to be the cause of an explosion that led to a fire at the Hoover Dam on Tuesday morning. Above, the famous dam is pictured in 2009.

An investigation into the specifics of what caused the Hoover Dam explosion is ongoing with no specific timeline for its findings, said local authorities.

An explosion at the Hoover Dam has prompted an emergency response from a Nevada fire crew, authorities said Tuesday morning. “We have a crew on the way where we have a report of a fire,” said ...

A transformer exploded at Hoover Dam, producing a thick cloud of black smoke and flames that quickly were extinguished.

Visitors at the dam Tuesday morning reported hearing an explosion and seeing fire, along with a large plume of smoke, coming from the dam. Video of the smoke was posted on social media.

Equipment failure caused a transformer at the Hoover Dam to explode, causing a fire that lasted about a half-hour and sending plumes of black smoke swirling through the air. Doug Hendrix, public ...

A Tuesday morning fire at the Hoover Dam was quickly extinguished, caused no injuries and is not a threat to the power grid, officials say.

An explosion at the Hoover Dam prompted an emergency response from a Nevada fire crew, authorities said Tuesday morning.

A transformer exploded at Hoover Dam, producing a thick cloud of black smoke and flames that quickly were extinguished.

A transformer exploded at Hoover Dam, producing a thick cloud of black smoke and flames that quickly were extinguished.