CLEAR LAKE SHORES — A gas leak at a home where work was being done on a gas-fueled furnace caused a small explosion that set a Clear Lake Shores home on fire about 10:20 a.m. Monday.

Workers from Bob’s Air Conditioning, a League City company, were in the attic at the time of the explosion. Kemah district fire marshal Larry Suniga said they escaped without injury. Firefighters also rescued a dog from the house.

The house is salvageable, but repairs to walls and floors are needed until it can be habitable again, Suniga said.

The small blast ignited part of the house and fire got under the pier and beam structure, Suniga said.

Firefighters extinguished the flames quickly, but the floors in the bathroom and hallway had to be torn out, Suniga said.

Fire investigators had not yet determined where the gas leak was that caused the fire, but Suniga said that, because workers were repairing the furnace, it was the first place they’d look.

The company was cited for violating a city ordinance because it didn’t have a permit to work on the house, City Administrator Paul Shelley said.

It’s the obligation of contractors to file for permits, he said.

One firefighter was treated at the scene for smoke inhalation, but she declined to be taken to the hospital, Suniga said.

League City, Seabrook, Bacliff and Kemah volunteer fire departments worked on the fire.