Clay Township, PA – A scary situation at a house in the township Monday night serves as a reminder for homeowners to have working carbon monoxide detectors, the West Sunbury fire chief said.

Butler Ambulance Service was dispatched Monday to a one-story house where a man and woman were reportedly ill, said Matt Wilson of the West Sunbury department.

Paramedics requested the fire department respond to check the house for carbon monoxide levels. Firefighters, wearing breathing apparatuses, entered the house and used hand-held meters to test the air. They recorded a reading of 647 parts per million.

“That’s the highest amount we’ve ever seen,” Wilson said.

In firefighter training, they learn that as little as 9 ppm in a home can cause symptoms, he said.

The typical CO level in a home with a properly adjusted gas stove ranges from 5 to 15 ppm, according to the U.S. Environmental Protection Agency.

The EPA describes CO as odorless, colorless and toxic gas on its website.

“Because it is impossible to see, taste or smell the toxic fumes, CO can kill you before you are aware it is in your home,” it says.

Symptoms of CO poisoning can include fatigue, chest pain, headaches, dizziness, confusion and nausea.