No one was injured and a preliminary investigation indicated a burst pipe caused the explosion, the university said in a statement. Foul play was not suspected.
There was no fire but a pool of what was believed to be liquid freon was seen on the floor at the California NanoSystems Institute, the school and Fire Department spokesman Brian Humphrey said. Hazardous materials teams were on scene.
"The building does not appear to be damaged externally, the damage appears to be within this area in the equipment room," he said.
According to its Web site, the NanoSystems Institute develops and promotes nanotechnology, which is extremely small technology on the scale of atoms and molecules.
Brenton Tarrant, the shooter from New Zealand's Christchurch, was not a lone wolf. The West has missed out an important point - the formation of organised Christian extremism
Those who convientenly blame Muslims and Islam for "extremism" and "terrorism" should rethink and read the living history for truth, honesty and justice
The Moroccan occupation remains the last case of decolonization in Africa. The Moroccan military invaded in 1975 despite a clear ruling issued by the ICJ.