Poughkeepsie, NY – Tom Costa checked out his Harrison Street rental property Thursday morning, only hours after the home is tagged inhabitable.

Five people were transported to area hospitals with carbon monoxide poisoning.

Poughkeepsie Fire Department Chief Mark Johnson said, “There was something going on there terribly wrong for a period of time to generate that amount of carbon monoxide.”

When crews arrived Wednesday night they found a disoriented man and a woman with a two-year-old daughter on the first floor. Upstairs they found two women unconscious. All were transported to area hospitals and one of unconscious women was later medivacced to Westchester Medical Center in critical condition.

The homeowner was too distraught to speak on camera but says in his 30 years of renting homes he’s never experienced anything like this. He added that when the tenants moved in back in October there was a working carbon monoxide detector inside the home.

But according to the chief, there were no detectors onsite. The chief says the problem was going untreated and only getting worse.

Lowe’s Plumbing and Heating mechanic Kevin Leahy said, “800 parts per million in a house is deadly. You’re looking for zero parts per million in a home. How they survived that is amazing.”

Officials say one of the women found unconscious had gone to the doctor complaining of a headache, which is one of the first signs of carbon monoxide poisoning.

Chief Johnson said, “It starts with nausea, headache, tired feeling as the concentrations rises you become disoriented, fall asleep and death eventually if it continues.”

And as the winter season nears and this type of situation becomes more common, mechanics stress the importance of annual heating system inspections.

Leahy said, “Make sure they are a certified heating mechanic have carbon monoxide detectors in your home and change your batteries.”

The homeowner is now working with the City Building Department and Central Hudson to get the grounds up to code.