BOULDER CITY, Nev. (AP) — A transformer exploded Tuesday at the Hoover Dam, one of the nation’s largest hydroelectric facilities, producing a thick cloud of black smoke and flames that were quickly extinguished.
No one was injured in the blast near the base of the dam, an engineering marvel on the Colorado River that straddles the border of Arizona and Nevada. Electricity continued to power 1.3 million people in Arizona, Nevada and Southern California.
The cause of the fire was under investigation and officials were working to determine the extent of damage to the transformer, one of 15 in the complex that controls supply voltages sent to customers.
“There is no risk to the power grid,” said Jacklynn Gould, regional director for the US Bureau of Reclamation.
The fire started around 10 a.m. and was extinguished within half an hour, Gould said in a statement. It caught the attention of tourists who quickly started recording and sharing videos on social media.
William Herro, 13, of San Francisco, was on an observation deck with his parents when he saw the explosion and then heard a “big boom”.
“A ton of black smoke just exploded in the air. It almost felt like a mushroom and then a fire followed,” Herro said. “I was really surprised and started filming.”
The explosion occurred on the apron of a building housing turbines that sits slightly downstream from the base of the dam, about 40 kilometers southeast of Las Vegas. The Hoover Dam is one of the tallest dams in the United States at 726 feet (221 meters). Each of its 17 generators can supply electricity to 100,000 homes.
Up to 20,000 vehicles per day cross the wide top of the dam, which is a National Historic Landmark and is seen in films such as “Transformers” and “Fools Rush In”.
The Bureau of Reclamation owns and operates the dam, power plants, and turbines. Electricity generated at the site is transferred to a substation where it is marketed through the Western Area Power Administration.
The Hoover Dam is considered a basic power source, which means it can respond quickly to the need for extra mains power or booster power.
The fire triggered an alert at the Western Area Power Administration control center in Phoenix. Spokeswoman Lisa Meiman said that while the loss of a transformer or other equipment on power plants can put a strain on a grid, “no single source is integral to the health of the power grid.” .
Hydropower from Hoover Dam and the upstream Glen Canyon Dam has recently been threatened by falling levels of Lake Mead and Lake Powell, the two largest man-made reservoirs in the United States that hold water from the Colorado River.
Federal authorities have taken steps in recent years to support the lakes to preserve the dams’ ability to generate electricity and keep water flowing to dependent western states and Mexico. Drought and climate change have plunged the lakes to their lowest levels in decades.
Fonseca reported from Flagstaff, Arizona. Associated Press writer Terry Tang in Phoenix contributed to this report.
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