Mystic — Firefighters quickly extinguished a blaze this morning that gutted a garage at 54 Denison Avenue.

The quick action by firefighters prevented serious damage to a house that is just 30 feet away. The heat from the fire, melted siding and blew out two windows on the side closest to the garage.

Mystic Fire Chief Fritz Hilbert said the first firefighter on the scene of the 10:30 a.m. fire found it fully involved in flames. Several bystanders helped him get a hose to the garage.

Firefighters from Old Mystic, Noank and the Naval Submarine Base also responded.

Hilbert said the fire was under control in about 10 minutes. There were no injuries, and the family dog, which was in the home at the time was not hurt. The heat caused no problems for firefighters.

Homeowner Lon Ackley, who was surveying the damage with fire officials early this afternoon, was sharpening a lawn mower blade in the garage about 30 minutes before the fire was reported, Hilbert said. Ackley had left the house and was not there when the fire was reported.

Hilbert said the cause has not yet been determined but it appears to be accidental. The state fire marshal was on the scene this afternoon helping with the investigation.

The house is located at the northeast corner of the intersection of Denison Avenue (Route 27) and Church Street.