Reported explosion at Hoover Dam was fire that has been extinguished, officials

The reported explosion at the Hoover Dam was in fact a fire that has been extinguished, officials said Tuesday afternoon.

Images and videos of dark smoke filling the sky over the dam filled social media. 

Officials said the fire was extinguished at about 10:30 a.m. local time, according to local TV station KRON-4. 

Tourist Kristy Hairston posted a video of what appears to be black smoke billowing out of the dam, with the caption, "touring the #hooverdam and heard an explosion #fire."

"Folks get your video on that, there's just been an incident here at the dam," a male authoritative voice states. "We're going to be leaving now so we don't get trapped in here." 

Another person says, "Something has just blown up."

The U.S. Bureau of Reclamation stated that around 10 a.m. local time, a transformer at the dam caught fire and was extinguished a half hour later.

"There are no injuries to visitors/employees. There is no risk to the power grid. Power is still being generated from the powerhouse," the agency wrote on Twitter.

The Hoover Dam opened in 1936 at the border of Nevada and Arizona.

Officials are still investigating the cause of the fire.