College Lab Evacuated in Chemical Scare : Explosives: Bomb squad removes dangerous chemicals and detonates one in a ravine when hazards are found at Irvine Valley campus.

The physical sciences building at Irvine Valley College was evacuated and some classes were canceled Thursday after a laboratory technician discovered a bottle of highly explosive and carcinogenic chemical leaking in a laboratory storage closet.

Fire officials found the explosive methyltrichlorosilane, plus a container of liquid sodium peroxide that had crystallized around the lid. Sodium peroxide is safe as a liquid, but once crystallized it can also explode if dropped, Fire Capt. Dan Young said.

The Sheriff’s Department bomb squad was called, safely removed the methyltrichlorosilane and detonated the sodium peroxide in a ravine at 8:30 p.m. Though the explosion “rattled a few windows,” it caused no damage, Young said.

The incident started about 2:30 p.m., when a lab technician entered the chemistry storage room and immediately “noticed something was wrong,” said George McCrory, a spokesman for the college at 5500 Irvine Center Drive.

The liter bottle of methyltrichlorosilane had leaked, and when the technician lifted the bottle, the bottom fell out, Young said. The container was half full.

Methyltrichlorosilane is highly flammable when exposed to air and water and is also carcinogenic, Young added.

Firefighters also found a less potent but still flammable chemical, acetyl chloride, in the storage room, Young said. Organic chemicals were also stored in the room, but they pose no serious threat, he added.

No injuries were reported, but one lab technician was taken to Irvine Medical Center for testing when she complained of a stiffness in the neck and spine, symptoms of exposure to a carcinogenic substance. Hoa Pham, 33, of Orange was released when the test results were negative, a hospital official said.

Three classes in the physical sciences building, which is mostly isolated from the rest of the campus, were canceled, McCrory said. About 20 classes were moved to other locations.

“It’s a waiting game,” McCrory said as he, faculty members and other curious onlookers watched firefighters in protective suits removing boxes of chemicals from the lab.

“We’re concerned with what’s going on. . . . We haven’t received any word” as to whether classes will be held in the building Friday, he said.

The bomb squad took the sodium peroxide to a ravine at the end of a parking lot, where a bucket of water had been set up, Young said. The chemical exploded shortly afterward.