When your carbon monoxide alarm goes off, you should probably call 911. That’s the word from the West Perth Fire department after a Mitchell family just narrowly avoided tragedy.

Three weeks ago the family’s alarms went off twice in the middle of the night. Both times the family reset them and went back to bed after opening some windows.

The next day they bought a CO alarm with a digital readout that confirmed those weren’t false alarms. They finally called the fire department which found their furnace was leaking the deadly gas.

Fire Chief Bill Hunter says you shouldn’t ignore your alarms and that they’d rather respond to 100 false alarms than one tragedy.