A fire that damaged a Richland home Thursday is believed to have been started by puppies that knocked over a heat lamp in the backyard.

Firefighters found the remains of one puppy, and believe a second puppy also died in the blaze. Some adult dogs were rescued from the house, said Richland fire Capt. Tom Huntington.

He did not know the dogs' breed.

The fire was spotted by Richland police Officer Rod Matheny while out on patrol in the neighborhood.

Matheny reported the fire at 10:51 a.m., and tried to call out to anyone inside after seeing a car parked in front of the house at 1210 Sanford Ave., said Richland police Sgt. Darryl Judge.

He did not enter the home to avoid the risk of feeding the fire with oxygen from outside, which can result in an explosion of flames known as a backdraft, Judge said.

Matheny then went door to door to alert neighbors and evacuate the area surrounding the home, Judge said.

Huntington said when Richland fire crews arrived, flames and smoke were coming from the back of the house.

Firefighters started attacking the blaze from outside, while also searching the home to make sure it was empty. Officials were then able to contact the home's occupant at work, who confirmed nobody was home.

Smoke was seen billowing out of holes firefighters cut in the roof. It took about 25 minutes to put the fire out.

The cause of the fire is under investigation, but it appears it started outside and worked its way inside to the attic, Huntington said. The tenant later offered the heat lamp explanation after seeing the damage.

"That seems to be what (investigators) are looking towards," he said.

Huntington did not have the tenant's name. Benton County property records show the house is owned by Gregory C. Parker of Richland, and is valued at $75,970.

Firefighters reportedly were told the lamp was in the yard to help keep the dogs warm outside.

The fire caused extensive damage to the back of the home outside and along an inside wall, and left heavy smoke damage throughout the house.

A doghouse was destroyed, Huntington said.

"The fire burned pretty hot," he said.

The tenant planned to stay with friends and did not ask for help from the Red Cross, he said.

Huntington did not know if the home is insured.

Crews from the Kennewick, Hanford and Pasco fire departments and Benton Fire District 4 also were on scene.