Rushford, WI – The condition of a woman being treated in the burn unit at the University of Wisconsin Hospital and Clinics in Madison for injuries sustained in a home explosion improved on Friday.

Toni Schult, 34, and her husband Steve Schult, 37, were hurt when an apparent natural gas leak caused an explosion Wednesday evening that destroyed the home. Both were initially listed in serious condition. On Friday, Toni Schult was upgraded to fair condition, according to a hospital spokesman. Steve Schult remained in serious condition Friday.

Investigators from the Winnebago County Sheriff’s Office ruled out foul play Thursday and handed the case over to the Omro-Rushford Fire Department and the Schults’ insurance company, said Capt. Steve Verwiel of the sheriff’s department.

The explosion originated in the basement of the home near the furnace and water heater. The cause of the gas leak in the home has not been determined, according to Fire Chief Russ Kleinschmidt, who expected the investigation to last several days.