Vehicle exhaust fills west Madison apartment with carbon monoxide

An occupant at 21 Sayner Court dialed 911 after a carbon monoxide detector inside their apartment building began to alarm. Ladder Co. 2 arrived to the eight-unit apartment building and immediately noted a strong odor of vehicle exhaust in the hallway just inside the front door. The crew used an air monitor to detect approximately 40 parts per million (ppm) of carbon monoxide* in the first floor hallway. Occupants were asked to evacuate to the outdoors for their safety.

Meanwhile, Ladder 2’s crew proceeded to the underground parking structure, where carbon monoxide levels increased to 104 ppm. There were only two vehicles in the garage and neither were running at the time. Firefighters also noticed that the garage’s exhaust system was not turned on. The overhead door was opened to attempt to get some fresh air into the garage.

Firefighters went door to door to obtain additional carbon monoxide readings. Some apartment units had 40 ppm and others had very little. Patio doors and window were opened.

Eventually, firefighters pinpointed a running vehicle parked outside emitting high levels of exhaust. The owner said the vehicle had been parked in the underground lot and found to have a dead battery. After a jump, he took the vehicle outside, where it had been running for the past hour. It is unknown how long the vehicle was parked indoors before being moved outside, but firefighters suspect this was the source of the carbon monoxide buildup indoors.

The incident led to the discovery of a malfunctioning garage exhaust system, which should have alarmed and self-activated upon detecting high levels of carbon monoxide. Firefighters alerted maintenance staff to the problem, and maintenance staff said they would have the system serviced Monday (3/6/23).

With a smile, the person who called 911 asked if they would get a medal for calling this in. The firefighters were lacking medals aboard Ladder Co. 2, but they were sincerely grateful that this person dialed 911 before anyone in the building became ill from the carbon monoxide. After a quick trip to the ladder truck, a firefighter returned to the 911 caller’s unit to say “thank you” and to award them a shiny silver badge sticker.

*Exposure to carbon monoxide can lead to illness and death depending on the level of carbon monoxide in the air and the amount of time exposed to it. Most people being experiencing symptoms after being exposed to at least 50 ppm of carbon monoxide for eight hours or more.