Las Vegas, NV – Las Vegas Fire & Rescue reports a woman was apparently killed Thursday night in a Northwest Las Vegas home by carbon monoxide poisoning produced from outdoor cooking devices used for heating.

The woman’s boyfriend flagged a passerby about 5 p.m. in the 6600 block of Crosstimber Court, near Gowan Road and Rainbow Boulevard, said Fire Department spokesman Tim Szymanski in a news release.

The boyfriend told the man he needed medical attention and that the woman inside the house couldn’t escape on her own, Szymanski said. Firefighters arrived to find “extreme amounts of carbon monoxide gas,” Szymanski said.

The woman was lying unresponsive in the stairs area on the second floor. Attempts to revive her were unsuccessful. The man was hospitalized.

After crews cleared the gas from the house, which took several hours, investigators found a power generator and two outdoor cooking devices believed to be used for heating, Szymanski said. Utilities in the house had been disconnected.

Outdoor cooking devices, like the ones found inside, produce “extreme” amounts of gases that can overcome humans with no warning, Szymanski said.

Szymanski reminded the public about the dangers of carbon monoxide, which is tasteless and odorless gas created by items such as stoves, furnaces water heaters, fireplaces, candles and anything else that produces a flame.

“Every home should have a carbon monoxide alarm along with smoke alarms,” he said.

Szymanski recommended one to be installed in a hallway and another in the kitchen.

“If your carbon monoxide alarm activates, you should evacuate your home immediately, go to a safe place outside and call 9-1-1 to have firefighters respond and check to see if the gas is in your home,” he said.

Thursday’s incident remains under investigation.