Electrical transformer explodes, startles visitors at Hoover Dam

An electrical transformer caught fire causing a large explosion at the Hoover Dam in Nevada. No one was injured.
Fire from a Tuesday morning transformer explosion at the Hoover Dam was quickly extinguished, caused no injuries and is not a threat to the power grid, according to the Bureau of Reclamation's regional director for the Lower Colorado Region.

Authorities are investigating what caused the fire, the federal Bureau of Reclamation said. In videos posted on social media, a huge plume of black smoke could be seen at the dam.