Witnesses say a large portion of the roof collapsed on a class on medical assistance at the North Orange County Regional Occupational Program Education Center at about 9 a.m. Students at the center range in age from 17 to 50.
The rain was very heavy when the roof gave way.
"All of a sudden, the front of the classroom, the ceiling just kind of collapsed," said Adriana Ferrari, who was inside the building at the time. "And then all of a sudden, the rest of it collapsed, and all the whole ceiling came down, and then everybody just started running."
Ferrari said the desks got pushed together in the chaos, and she got stuck underneath the mess while her friend was trampled.
"We didn't know if we were going to get electrocuted because of the lights falling. Literally the whole ceiling came down," she said.
Rescuers went inside the building three times to do searches and believe everybody who was inside are now out.
Authorities said there were four drains on top of the roof, and one of those drains failed, causing the water to build up.
About 100 to 150 students attend the school, but officials were unsure how many were inside the building at the time of the collapse.
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