BRENTWOOD -- A boat storage area and the roofs of two nearby homes were damaged Thursday evening in a fire on Sandmound Boulevard.

Officials are investigating the cause of the blaze, but neighbors reported hearing fireworks before the fire was reported at 7:30 p.m., said East Contra Costa County Fire Chief Hugh Henderson.

The fire started in some grass on the 5500 block of Sandmound Boulevard, then spread to a nearby boat storage area. Embers from the fire blew high up into the air and lit the roofs of two nearby homes -- one adjacent to the storage area and a second across the street, Henderson said.

Firefighters quickly called in reinforcements from neighboring fire departments and extinguished the blaze in about 20 minutes. Seven engines from East County Fire, Pittsburg and Antioch responded to help control the fire. No injuries were reported.