Car Left Running Inside Garage Triggers Carbon Monoxide Alarm

A carbon monoxide detector began to sound in the second-floor bathroom of a west side home in the middle of the night, prompting a 911 call and response from the Madison Fire Department.
 
The occupant waited outside with her dogs until Ladder Company 7 arrived at her door. The alarm was no longer sounding when they approached, but their Sensit air monitor picked up carbon monoxide levels at around 60 parts per million.
 
The crew searched the house for the source, and upon opening the garage door they found the resident’s car still running. Carbon monoxide levels jumped to more than 200 parts per million at the entrance of the garage.
 
Firefighters ventilated the home until CO levels returned to the normal range, fewer than 3 parts per million.