PORTSMOUTH -- Investigators say two people died from apparent carbon monoxide poisoning Wednesday morning.
Capt. Paul Hoyle says investigators discovered a gas-powered generator operating inside the Spruce Street home.
The victims have been identified as Isaac Bowser, 47, and William Lashley, 86.
A third person, Lashley's wife Brenda, was taken to the hospital in critical condition from the home at 2516 Spruce Street.
She was found in a back bedroom with the door closed.
Investigators discovered a gas-powered generator operating inside the single-family home, Hoyle added.
Crews were called to the home after receiving a call from a contractor doing work at the house.
According to the homeowner, a couple has rented the home for that last nine years. He also said he didn't know there was no electricity in the home.
Reggie Bell says the third person in the home was a co-worker who needed a place to stay for while.
Bell says there was power when he visted just two days ago.
"So, I don't know what happened. My cousin was looking for somewhere else to move. It's hard that things are getting like this people have to resort to this," he said.
There are many sources of carbon monoxide around the house that can potentially cause problems.
An air quality expert told 13NEWS that portable gas powered appliances should never be inside, or any place where the fumes cannot be easily dispersed.
Other potential carbon monoxide hazards are charcoal and gas grills.
They need to be in an open area, but you want to make sure they are not close to ventilation systems which could pull the smoke into your home.
Fireplaces, wood burning stoves, and running lawnmowers are also possible problem areas.
One of the best protections is to make sure you have carbon monoxide detectors to warn you of a leak.
Otherwise the colorless, odorless, gas can be mistaken for something else.
"Headache, even flu like symptoms, nausea, that's talked about a lot, getting severely sick," said Stanley Yeskolski, from Investigative Inspection SVCS.
Even low levels of exposure can cause problems, especially for pregnant women.
Having a carbon monoxide detector in your house is the best way to protect yourself.
They are available for as little as 20 dollars.
Hoyle says the Portsmouth Fire Department will assist residents with information and installation of carbon monoxide detectors they have.
Associated Press contributed to this report.