Kent, WA – Three people were hospitalized Wednesday after they were exposed to carbon monoxide fumes from a malfunctioning furnace, emergency officials said.

Firefighters initially responded to the home in a Kent neighborhood at about 8:20 a.m. after receiving reports of multiple residents there feeling sick and confused.

The first arriving crews got an alarm on their carbon monoxide meters and upgraded the call to include a hazardous materials team and medics.

Three people were treated at the scene then taken to a local hospital.

An investigation found that the source of the toxic monoxide fumes was a malfunctioning furnace in the home.