Emergency repairs were needed at the Sarnia Police Service facility on Christina Street.
Earlier this month, the boiler system failed and the service said both boiler units were taken out of service for safety violations and replacement.
An inspection by an HVAC contractor found a disintegration of the internal exhaust stack, which was found to be introducing carbon monoxide (CO) into the cabinet and the room.
The report said with colder temperatures, emergency repairs to provide heat throughout the building were necessary.
A replacement of the faulty unit was conducted on January 15 at a cost of $175,000.
Funds were taken from the Police Building Equipment Reserve Fund.
In 2023 repairs and upgrades were completed in the shooting range due to lead concerns.
Also in 2023, a transformer was replaced at the 38-year-old building.