GRAND FORKS (AP) - A Grand Forks couple apparently died from inhaling toxic smoke from a kitchen fire they thought had been put out, fire officials say.

The bodies of Bridget Ann Hayes, 50, and Harry Tetrault, 65, were found in their home late Wednesday afternoon by a relative who went to check on them, fire officials said.

Fire Marshal Bruce Hoeger said the two apparently died of toxic fumes from a fire that started from a portable plastic radio placed on a hot plate the day before.

"We haven't gotten results of the autopsy yet, but there appears to be no other cause (of death)," Hoeger said Friday.

Damage to the house was estimated at about $2,000, he said. A burning radio had been dumped in the sink, and fire burned some of the countertop, he said.

"They thought it was out, didn't get the smoke ventilated out of the house well enough," Hoeger said. "When plastics burn, they put out a very toxic smoke with hydrogen cyanide, hydrogen sulfide - there's a whole list. It doesn't really take that much. Some of those gases, you think you have the place cleaned out, and they're still there."

The house had a smoke detector but the battery was dead when firefighters tested it, Hoeger said.

The man's body was found in the bed and the woman's body was near the front door, he said.

"Fire itself kills very few people," Hoeger said. "It's the smoke that kills most of the people killed in fires."