The explosion was reported about 7:30 a.m. at the Biscailuz Training Facility, Los Angeles County Sheriff’s Department spokesperson Nicole Nishida said. It was not immediately known what caused the explosion or what the deputies were doing at the time.

Senior law enforcement officials said the LASD bomb squad responded to a garage in Santa Monica yesterday, where at least one grenade was found. It was transported to the training facility, where the deputies were working to render it safe,