By Neale Gulley

BUFFALO, New York (Reuters) - A house exploded into flames on Tuesday in western New York, killing a teenager and injuring four members of her family who were blown into the home's yard, authorities said.

The blast leveled the Wilson, New York, house on Lake Ontario, about 30 miles north of Buffalo, Niagara County Undersheriff Michael Filicetti said.

"There was fire and explosion. There is nothing left. It's leveled," Filicetti said.

The cause was unknown, he said, although someone in the home complained on Monday of smelling the odor of the additive in natural gas. He said it was unclear who made the report and to whom.

The body of Sarah Johnson, 14, was found amid the debris of the 2 1/2 story home, Filicetti said, about two hours after the morning blast.

The girl's parents, Jody and Judith Johnson, her sister Katie, 18, and her brother Nathan, 16, were blown out of the house by the force of the explosion and survived.

"It's believed that the force of the blast actually forced them out of the residence," Filicetti said.

The family was being treated at a local hospital, where the 18-year-old's condition was listed as critical due to severe burns.

Two other family members, Hannah, 16, and Sam, 10, were not home at the time.

(Editing by Ellen Wulfhorst and Stacey Joyce)