A tourist at the Hoover Dam shared video Tuesday showing a small explosion and black smoke.
"My goodness, something's just blown up," a woman is heard saying in the video first shared by Kristy Hairston, who said she was touring the dam Tuesday and heard an explosion.
A male's voice, perhaps the security guard or tour guide, is also heard noting the explosion and fire at the dam below.
An account for Boulder City, Nevada, later tweeted that the fire was extinguished before the Boulder City Fire Department arrived at the scene.
The Bureau of Reclamation, the federal agency under the U.S. Department of Interior, which runs the Hoover Dam, said a transformer caught fire and was extinguished by the Reclamation/Hoover fire brigade around 30 minutes later.
"There are no injuries to visitors or employees," Michelle Helms, spokesperson for the Bureau of Reclamation, told Fox News Digital. "There is no risk to the power grid and power is still being generated from the powerhouse. We are investigating the cause of the fire and will provide additional updates as they are available."
Additional details regarding the circumstances of the incident captured on cell phone camera at the hydroelectric power plant located in Clark County, Nevada, were not immediately clear.
The Hoover Dam, constructed between 1930 and 1936, sits in the Black Canyon of the Colorado River on the border between the Nevada and Arizona and is the highest concrete arch dam in the United States.
The dam forms Lake Mead, the country's largest man-made water reservoir, which serves water to the states of Arizona, California, Utah, Colorado and Nevada, as well as parts of Mexico.
It provides fresh water to nearly 20 million people and farmland.