GRAND ISLAND, Neb. (AP) — A man has died and eight other people — including firefighters and a police officer — have been treated for carbon monoxide poisoning in Grand Island.

Firefighters were sent to a home Tuesday on a medical call. They found the man and a woman in the basement. Authorities say the two were taken to a local hospital, where the man was pronounced dead. An autopsy has been ordered. The woman’s condition hasn’t been released.

The two people’s names haven’t been released.

Carbon monoxide monitors warned firefighters and the police officer of their exposure, so they were treated at the hospital as well. They were discharged after three hours of treatment.

Fire officials blamed the carbon monoxide buildup on unvented gas-powered space heaters.