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.
Malaysia needs Russia's assistance in maintaining and repairing Su-30MKM fighter jets
Japanese Prime Minister Shinzo Abe said that US army bases will not appear on the southern Kuril Islands in the even Russia delivers them to Japan
Posters for the play "Adam and Eve. Life after Paradise" with pictures of dancers Arsen Aghamalyan and Oksana Vasilyeva were banned in the city of Tver, Central Russia