Possibly four - I posted this on a different tread:
My wife is a graduate student at UCLA and has an apartment at Weyburn Terrace, about two blocks south of Midvale Plaza. Her apartment is across an alley from Warren Hall, which I understand is a biochemistry building. She called me about 1AM Monday morning, 10/03/05, in a panic. She was awakened by a load explosion that shook her bed and rattled the walls. She went outside to find a cloud of smoke and fumes drifting towards Weyburn Terrace. She found an eyewitness among the students from all the surrounding apartment buildings who had also come outside. The eyewitness said that he had been on his balcony, smoking, when he saw a bright flash that appeared to come either from the second story or the roof of Warren Hall. Upon the arrival of the fire department and the police department, my wife went back to her apartment because she didn't know what was in the fumes. According to my wife, after looking around a bit, the firemen and police ascertained that all was o.k. and they left. At 4AM a second explosion occurred. This time my wife just looked outside, saw the comotion and went back to sleep.
My wife checked the Daily Bruin the next day and found nothing concerning the explosions. We have since checked the internet several times and have found no information concerning the explosions. One would think that this would be newsworthy event, even if it were accidental.
Daily Bruin article about the explosion is here:
http://www.freerepublic.com/focus/f-news/1500285/posts