Failed Heat Exchanger Results in Carbon Monoxide Exposure

Location: Surrey

Regulated industry sector: Gas – Natural gas system

Incident overview

In a townhome, a residential gas furnace heat exchanger failed after excessive corrosion of its polypropylene laminated steel components. The airflow was restricted, resulting in the production of carbon monoxide (CO) due to incomplete combustion. An incorrectly installed vent with a 90-degree elbow directed high levels of CO below the deck, where the gas was drawn back into the home through a passive air intake. Two children were exposed to CO, experiencing nausea and vomiting. Investigation found that redundant safety features, like the flame rollout switch or proving switch, were not able to control the CO hazard.