Hazmat was called in to the scene of a fire in La Jolla Monday night due to possible hazardous materials inside the building.
According to the San Diego Fire-Rescue Department (SDFD), the fire began around 8:53 p.m. inside Ritter Hall on the 8600 block of Discovery Way.
A battery that powers a sonar sensor used to study whales short-circuited, popped and caused a small explosion, according to SDFD.
When crews arrived on the scene, there was light smoke coming from inside a laboratory.
As a precaution, Hazmat was called to the scene after crews saw old radioactive hazard signs around the building.
The scene was cleared as of approximately 10:30 p.m.
Only the battery was damaged, SDFD officials told NBC 7.
No other information was available.