Most students at the University of California at Berkeley campus were heading back to class on Tuesday morning following an explosion and power outage authorities believe was sparked by a copper theft.
Cal's News Center said early Tuesday morning that most buildings on campus had power back and classes would resume as normal except for thoses held in the 11 buildings that aren't operational. Click here for the full list. Students in those classes should check with their academic departments for updates.
A massive power outage was reported at 4:40 p.m. Monday on the Cal campus, causing a powerful explosion in a generator vault, between California and Durant halls, two hours later. The entire campus was evacuated after the incident, which sent one person to the hospital with minor injuries and left four others with minor burns, according to university spokesman Dan Mogulof.
The fire was put out about 8:15 p.m. YouTube video posted on the Daily Californian website showed smoke billowing out from campus, and students screaming and walking hurriedly as voices on megaphones ordered their evacuation.
Students on Tuesday immediately took to Cal's Facebook to question whether the campus was safe. "How can you cancel class for some yet allow others to walk around campus?" Tucker Kahn posted on the campus website.
Another person, identified as Lientra Lu, wrote that there was an amonia leak at Latimer Hall, and wondered how safe she was and if she endure the smell. Campus spokesman Bob Sanders on Tuesday told NBC Bay Area that some amonia fumes did escape under a fume hood on Monday, but firefighters have since checked it out and deemed it safe because nothing spilled.
Other students recalled what it looked and sounded like when the explosion ripped through campus.
"Essentially there was a massive fireball that erupted," Colin Ho said on Monday evening. "The fireball was two times the height of the building, and everyone just got the hell out of there."
One person on Twitter wondered if there would be no school because of "explosion day."
So can we get an explosion day tomorrow? #NoSchool
— Clare OBrien-Lambert (@clareolamb) October 1, 2013
The explosion happened at an underground electrical vault outside California Hall near the center of campus as crews were attempting to repair damage caused by a copper wire theft last week.
"The explosion occurred when university engineers were bringing power back online," Mogulof said at a news conference. "It now appears the damage caused by these unknown individuals was far more extensive and far more significant than seen and assessed."
Campus officials canceled classes Monday night and sent out an emergency message to students' cell phones and e-mail inboxes alerting them of the explosion and that they leave the main campus area immediately. It is still unknown if classes will resume on Tuesday.
About 20 people couldn't leave the campus, because they were stuck in elevators during the outage.
Video posted on YouTube by the Daily Californian:
NBC Bay Area's Kristofer Noceda and Shelby Hansen contributed to this report.