What to do if you smell gas

Leave the building. Call your gas utility or 911 from outside. That is the whole procedure. Everything below is detail.

Do

• Get everyone (pets included) out immediately, leaving the door open behind you.
• Call your gas utility's emergency line or 911 once you are away from the building. Utilities respond to gas odor calls 24/7, free.
• If it is safe to do so on your way out and you know where it is, shut the outdoor gas meter valve, but only if it is on your path and takes seconds.
• Wait for the all-clear before going back in, even briefly.

Do not

• Do not flip any light switch, on or off. A switch can spark.
• Do not use phones, garage door openers, doorbells, or anything electrical inside.
• Do not light anything, obviously, but also do not start a car in an attached garage.
• Do not open windows to “air it out” while you are still inside; just leave.
• Do not try to find the leak yourself.

A faint whiff at the furnace on first startup of the season?

Dust burning off a heat exchanger after a summer idle smells scorched, not like gas, and clears in under an hour. Rotten-egg odor is the gas odorant (mercaptan) and is never normal. If you are unsure which you are smelling, treat it as gas and make the call. Utilities would far rather check a false alarm.