Carbon Monoxide Release at Animal Shelter

Location: Maple Ridge

Regulated industry sector: Gas – Natural gas system

Incident overview

A wall-hung condensing boiler exhausted flue gases containing carbon monoxide (CO) into a rooftop mechanical room at an animal shelter. Overnight, the CO entered office spaces on the main floor of the building. Staff members working the next day experienced symptoms of carbon monoxide poisoning and evacuated the building, along with the animals. Investigation found that the removal of the condensate trap from the boiler by qualified technicians during a troubleshooting event, caused flue gases to enter the mechanical room and spread into other rooms of the building through a filter gap in the air handling unit. The building did not have CO alarms installed, which would have provided an early warning of high CO levels for the staff members.