California's Berkeley campus evacuated after electrical blast, outage

One of the injured was taken to a hospital, Mogulof said. The other two to three people declined medical aid, according to a statement on the school's website.

At around 6:30 p.m., about two hours after a power outage at the campus, engineers were beginning to bring power back online when the explosion in the vault occurred, Mogulof said.

The power outage and explosion appear to stem from damage to the university's electrical system caused by vandals stealing copper wiring, he said.

The vandalism was first discovered late last week, Mogulof said. "It now appears the damage the vandals caused was far more extensive than we could see or assess at the time," he said.

The school said in an online statement shortly after 8 pm local time that email had been restored on campus and other systems were being restored.

Officials have not determined when they will be able to re-open the campus to students, he said.