If the alarm is sounding, evacuate immediately and call emergency services or the gas company from outside
Do not try to disable the alarm while anyone may be exposed to carbon monoxide
If it is a false alarm and you are certain the area is safe, press the test/silence button
Open windows and doors to ventilate the area
Check for possible sources such as fuel-burning appliances, fireplace, furnace, generator, or attached garage
Replace the battery if the alarm is battery-powered and chirping
Reset the alarm according to the manufacturer’s instructions
Replace the alarm if it is expired or malfunctioning
If the alarm is hardwired, turn off power only if the manufacturer’s instructions allow it and the area is confirmed safe
Contact a qualified technician if the alarm keeps sounding or you are unsure of the cause