LANSING, Mich. (AP) — A man and woman who were found dead last weekend in a Lansing apartment where a gasoline-powered generator was operating most likely died from carbon monoxide poisoning, officials said Tuesday.

Lansing police spokeswoman Jordan Gulkis said officers went to the residence on Saturday afternoon and found a 51-year-old man and a 42-year-old woman dead inside, the Lansing State Journal reported.

Toxicology tests on the man and woman are pending with the local medical examiner’s office, but based on the circumstances found at the scene, with the generator operating inside the apartment, it appears they died from carbon monoxide poisoning, said Lansing Assistant Fire Chief Mike Tobin.

Carbon monoxide is a toxic, odorless gas that is produced by combustion. It can be found in fumes produced by automobiles, generators, gas ranges and heating systems.

“When my fire crews got to the scene, the generator was still in the apartment and operating so we’re suspecting carbon monoxide,” Tobin said Tuesday.

Tobin said the apartment, located in a townhouse, is in a south Lansing neighborhood where all of the buildings were without power following last week’s severe storms and tornadoes blamed for five deaths across Michigan.

Fire crews didn’t investigate the source of the outages in that neighborhood, but Tobin said they were most likely caused by last Thursday night’s severe weather.

As of 3 p.m. Tuesday, more than 14,000 homes and businesses remained without power in Michigan, according to the Poweroutage.us website. That’s a fraction of more than 460,000 homes and business that were in the dark in the state shortly after last week’s storms.