Building Evacuated For Carbon Monoxide Leak; Everybody Okay

Approximately 25 people and their pets were evacuated from their apartments at 427 W. Main Street due to a carbon monoxide (CO) leak.
 
Ladder Company 1 was dispatched to the three-story complex after CO alarms throughout the building activated. Firefighters detected CO levels around 40 parts per million (ppm) upon entering the building, and those levels remained constant as the crew traveled from ground level to the third floor.
 
Firefighters asked MGE to join them at the scene as they began knocking on doors trying to determine the CO source.
 
Ladder 1 went to the basement laundry room where they found another door which they forced open. As soon as that door was opened, their air monitors detected CO levels at about 700 ppm. Firefighters immediately retreated and began asking residents to evacuate the building. They also retrieved their fan from the Ladder truck and started to ventilate.
 
Upon their arrival, MGE turned off the water heaters inside the room that appeared to be at the center of the CO leak. A Madison Metro bus was called in to provide shelter from the freezing rain for the temporarily-displaced residents and their pets.
 
CO levels returned to 0 ppm after thorough ventilation took place. Residents were welcomed back inside shortly thereafter, but they were advised there would be no hot water in the building until further notice.