Two firefighters and two civilians were exposed to an unknown chemical while the department was investigating an automatic fire alarm Wednesday evening in Irvine.
The exposure took place in a room at a house in the 17000 block of Cowan about 6:45 p.m., the Orange County Fire Authority reported.
The four people exposed all suffered minor symptoms, according to the OCFA. It was not known if any of the four were hospitalized.
An OCFA Hazmat team was called to the scene to investigate the chemical, the department reported.