CHICAGO (CBS) — Nine people are in the hospital Friday morning, after a carbon monoxide leak at a home in the Humboldt Park neighborhood.

Fire Department officials said paramedics responded to call about someone who fell Friday morning at a home in the 600 block of North Sawyer Avenue, and while inside the home, sensors the paramedics routinely carry alerted them to high levels of carbon monoxide in the house.

The Fire Department initiated a hazardous materials response and brought in several ambulances.

Eight adults and one child from the home were taken to hospitals to be treated for carbon monoxide exposure, but they are expected to be okay. A Fire Department spokesperson said the paramedics saved those people’s lives by discovering the carbon monoxide leak.

A Chicago Fire Department paramedic shows off a wearable carbon monoxide sensor they routinely wear as part of their uniform. (Credit: CBS)

Chicago Fire Commissioner Richard Ford II said the people inside the home had no idea there was a leak.

“Carbon monoxide is odorless and tasteless, and you don’t know it’s an elevated level that could be dangerous to humans until a meter goes off, or someone with a meter comes in,” he said.

It was not immediately clear what caused the carbon monoxide leak.

Crews opened all the windows in the house to clear out the dangerous levels of carbon monoxide.