It happened at 4 p.m. at a three-story science building on 923 Bloom Walk. Los Angeles firefighters said one person - who was not identified - was sent to the hospital in an unknown condition.
Firefighters evacuated everyone out of both the Neely Petroleum Engineering building and Hedco Chemical Engineering building. Investigators said crews checked every floor of the building and found no hazards or leaks. They said all air readings (conducted via a handheld gas meter) came out normal.
No other injuries reported. Both buildings have since been reopened.
Investigators are still working to figure out what exactly caused the explosion.