BERKELEY -- Officials on Tuesday were investigating a power outage followed by an explosion and three-story fireball on Monday at UC Berkeley that sent one student to the hospital with minor burns -- the second explosion and power outage on campus in a little over two weeks and the third this year.
A previous explosion Sept. 12 in a high-voltage underground vault caused a three-hour power outage to six buildings. On Feb. 14 there was an explosion at a substation followed by a power outage, said Christine Shaff, spokeswoman for the campus facilities department. No injuries were reported in those two explosions, Shaff said.
On Tuesday, 11 buildings remained without power and 113 classes were canceled, according to campus spokesman Dan Mogulof. He said "it is not clear" whether the canceled classes will resume Wednesday. About 20 people were stuck in elevators on campus Monday and were rescued by Berkeley fire crews.
Mogulof said the university hoped to have power restored to California Hall, Dwinelle Hall, the Bancroft and Doe libraries and one or two other buildings by Wednesday.
Mogulof said the power outage was caused by the theft of copper grounding wire stolen from an underground area accessible by a manhole cover at the university last week. Workers thought they had the damage repaired on Sunday, but the damage was more extensive than thought and caused Monday's power outage, Mogulof said. He did not know if all three explosions this year were due to copper wire thefts.
"The fact that they were able to locate the manhole cover and apply the sort of pressure they did to the wires leads us to believe this was a sophisticated operation and not a bunch of teenagers doing some sort of vandalism," Mogulof said.
Officials are not sure if the explosion and fireball were related to the power outage and it's not known exactly how much copper wire was taken, Mogulof said.
"We're in a new world where people are stealing copper out of the university power system, so we have to adapt," Mogulof said.
Shaff said she was walking near California Hall on campus on Monday when she heard the explosion and saw the fireball, which was right next to the chancellor's office.
"It looked like something right out of a movie," Shaff said. "Then the fire continued underground. There was a fire truck right next to it that was on campus to monitor the power outage."
Asked why the campus has experienced two explosions and power outages in a little over two weeks, Shaff said the power system on campus is old and the university is doing its best to upgrade it as fast as it can.
The 11 buildings that remained without power on Tuesday included Haas Pavilion, the Bancroft and Doe libraries, Alumni House, California Hall, the Central Heating Plant, Durant Hall, Dwinelle Hall, Dwinelle Annex, Edwards Track and the Environmental Health and Safety Building.
The outage was first reported Monday around 4:45 p.m. and the explosion, in an electrical vault outside California Hall in the heart of campus, occurred around 6:30 p.m.
Campus officials worked through the night and early morning to restore power to all but the 11 buildings. Generators provided power to off-campus residential halls.
Four people suffered minor burns. Three were treated and released without visiting a hospital. The one person hospitalized for burns was released, Mogulof said.
Those stuck in the elevators were freed by 8:30 p.m., officials said.
Students were advised to check with their academic departments for more information about rescheduling of classes or events, and employees working in the affected buildings still without power were asked to check with their supervisor about reporting to work.
Staff writers Erin Ivie and David DeBolt contributed to this story.