A structure fire at 4191 George Ave. in San Mateo displaced an apartment’s occupants and caused around $20,000 in damage Monday evening, according to San Mateo fire officials.

At approximately 5:08 p.m., firefighters were dispatched to the blaze in the upper unit family room of a two-story apartment complex. The fire was quickly extinguished and contained to the room of origin, according to fire officials.

The occupants were not injured but could not stay in the unit. The fire’s cause is under investigation, according to fire officials.