An underground electrical transformer vault exploded Tuesday in Westwood near UCLA, sending smoke and a plume of flame shooting up from the street and propelling a manhole cover into the back of a Metro bus, Los Angeles city fire officials said.
None of the 25 passengers on board were injured, even though the back of the bus was passing over the manhole when the cover blew, shattering the vehicle's rear windows.
The blast, which occurred near Westwood Boulevard and Weyburn Avenue about 9:30 a.m., temporarily halted traffic. The bus was southbound on Westwood, Metro said.
Residents and workers in the densely packed area said they were startled as nearby windows either shattered or shook as lights flickered. The Department of Water and Power said that a junction box failure triggered the explosion and that an investigation is being conducted into what caused the failure.
Elaine Schmidt, a UCLA spokeswoman who works in a building on the block where the blast took place, said it "felt like a large truck had landed on top of the building."
"We heard this big boom," Schmidt said, noting that she looked out a window and saw a "big plume of fire and brown smoke coming from the street."
Schmidt said she could see the damaged bus and parts from it strewn about. She said she also saw the bus driver, who ran from his vehicle and put up traffic cones around the area to stop traffic.
"He looked pretty shook up," Schmidt said. "It was remarkable because he was probably deafened by the explosion."
Windows at the Bank of America branch on Westwood Boulevard were blown out, said Schmidt, whose office is in the building that houses the bank. She added that the explosion caused many workers in the building to quickly file from their offices, some of them concerned that a terrorist attack might have taken place.
Joyce Croker, a manager at the UCLA Extension offices a few blocks away, said the explosion sounded like a "really loud crack that we actually thought was a lightning strike."
UCLA officials said the blast also interrupted power at the campus for a short time, and that emergency generators took over until power was restored.