The University of California at Berkeley campus was evacuated Monday night after an explosion injured at least one person and caused a power outage.

About 20 people were also trapped in dormitory elevators as a result of the outage, reported The Bakersfield Californian.

The power outage was reported about 4:30 p.m. and all classes were canceled.

Authorities reported an ammonia leak about a half hour later in a room at Latimer Hall, followed by an explosion just before 7 p.m. near California Hall.

At least one person was hospitalized with non-life-threatening injuries by the blast, although several other people suffered minor injuries but refused treatment at the scene, university officials said.

A university spokesman said the explosion may have been caused by an attempted underground copper wire theft last week on the campus.

Officials aren’t certain whether all the incidents were related or what caused them.

'Ambulance Parked At Hospital' [Shutterstock]