A power outage and explosion at the University of California at Berkeley Monday afternoon was connected to a theft of copper wiring, a university spokesman said.
The campus-wide power outage began at about 4:40 p.m. on Monday, according to university officials.
Power had been restored to all but 11 buildings by 8 a.m. Tuesday.
Monday evening classes were canceled and all labs were shut down because of the outage. As part of ongoing power issues 113 classes were canceled Tuesday.
The power system failure was followed by an explosion and fire in an underground steam tunnel between California and Durant halls at about 6:40 p.m. that shrouded the campus in smoke, university officials said.
The explosion led to a call for an evacuation of campus. The fire was extinguished by 8:15 p.m.
One student suffered minor injuries and was transported to a medical facility and later released, according to university officials.
During the outage, about 20 people were stuck in elevators in affected buildings, but all were freed by 8:30 p.m., according to university officials.
University officials have confirmed the outage stemmed from a theft of copper wiring sometime last week from an area about a half-mile east of campus, university spokesman Dan Mogulof said.
Eleven buildings remained without power throughout Tuesday and crews are installing generators to power the buildings, including Dwinelle Hall, which hosts numerous academic courses.
The group of buildings will not be reconnected to the campus electrical grid until officials complete an assessment of the outage and fully understand the cause of the explosion, Mogulof said.
Mogulof said it is uncertain how long that assessment will take, but the buildings will run on generators in the meantime to avoid the chance of another incident.
Despite many canceled classes Tuesday, officials expect classes to resume Wednesday morning.
"We have a high degree of confidence that we'll have full array of classes by Wednesday," Mogulof said.
Classes and events that were scheduled to meet in Alumni House, Bancroft Library, California Hall, Central Heating Plant, Doe Library, Durant Hall, Dwinelle Hall, Dwinelle Annex, Edwards Track, Haas Pavilion and the Environment, Health & Safety Facility were not held Tuesday.
"It was a significant disruption for students in those classes," Mogulof said.
University officials asked faculty and staff to be understanding and accommodating for students who may have come unprepared to classes Tuesday.
Many students at residence halls did not have power restored until late Monday night or early Tuesday morning, and may not have been able to use computers or have adequate lighting for reading and writing assignments.