PICO-UNION (CBSLA) — A vault explosion knocked out power to roughly 2,500 people Thursday evening.

The explosion happened at about 6:33 p.m. in the 1700 block of West Olympic Boulevard, but workers with the Los Angeles Department of Water and Power was unsure of the cause.

It was first reported as smoke coming from a manhole in the street, but when firefighters arrived on the scene, they found that an underground cable failed. There were no injuries reported.

LADWP said it expected power would be restored by 11 p.m.