SUNSET BEACH, Calif. (KTLA) -- Hot briquettes from barbecue are being blamed for a five-alarm fire that destroyed one beachfront home and badly damaged at least two others along Pacific Coast Highway.

The initial fire was reported in the 16500 block of South Pacific Coast Highway at 4:50 p.m.

The flames quickly spread from one house to another in the row of tightly-packed homes.

Quick action by firefighters using water cannons kept the fire from reaching a third house, but it did sustain water and smoke damage.

At one point, one of the burned homes collapsed as firefighters worked nearby.

Fire investigators believe a spark from a flaming briquette blew from a deck barbecue and caught the underbelly of the wooden deck on fire.

Two people were treated for minor smoke inhalation, but neither had to be hospitalized.

Flames were still visible late Thursday, as firefighters continued to try to contain the fire.

About 100 firefighters from Newport Beach, Huntington Beach, Fountain Valley and the county fire authority were called in to fight the blaze.

The cause of the fire is now under investigation.

PCH was closed between 22nd Street and 19th Street.