Wilmette, IL- Wilmette fire department officials rescued two senior citizens from their carbon monoxide-filled home late last week.

Firefighters responding to the Friday incident measured carbon monoxide levels of 300 to 400 parts per million inside the Oak Circle house, Fire Chief Ben Wozney said. Carbon monoxide detectors normally sound when they register levels of roughly 35 parts per million, he said.

The house had no carbon monoxide detectors, Wozney said.

The incident began around 11 a.m., after dispatchers received a call from someone feeling ill.

As soon as firefighters entered the home on the 300 block of Oak Circle, “we felt a heavy quality to the air,” firefighter-paramedic Mike Lettieri said.

“The gas itself is odorless and tasteless, but levels were so high that we were able to come in from the outside and immediately feel that something was off,” firefighter-paramedic Bill Durband said.

Durband said two residents in the house, a man and woman in their 80s, were feeling effects of the gas. The man was experiencing mild confusion while the woman was nauseated and vomiting, he said.

Both improved soon after paramedics helped them out of the house and treated them with oxygen, Lettieri said. They were taken to Skokie Hospital for evaluation and observation, he said.

Wozney said Monday he didn’t know whether either of the two remained in the hospital.

Members of the fire crew traced the monoxide leak to the boiler, where the levels of carbon monoxide were close to 400 parts per million, Durband said.

Firefighters shut off gas to the boiler, and crews left the scene after about an hour and a half, Durband said.

Wozney said all residences should have carbon monoxide detectors outside every bedroom, and in general areas on non-sleeping floors. The detectors cost between $30 and $100 and can be wall or ceiling mounted, he said, and should have the Underwriters Laboratory seal.

“The batteries need to be changed every six months, just like a smoke detector,” he said. “The detectors themselves should be changed out every five to seven years, depending on the brand.”

Residents should also make sure their furnaces, boilers and water heaters are inspected annually, Wozney said. Fireplaces should also be checked; residents who regularly use their wood-burning fireplace should have the fireplace chimney checked annually, he said.

“The number one thing that we want to get across to everybody is that every home should have working carbon monoxide detectors,” Wozney said.

The Nov. 24 incident was the first incident this year in which the fire department had to transport someone to the hospital for carbon monoxide inhalation, he said, but not the first time this year that crews have responded to working monoxide alarms.

“Typically we respond to a few minor leaks that we detect early because of working alarms,” he said.

The last time the department dealt with a situation in which residents had to be treated in a hospital was several years ago, he said.