Do not try to locate the source of the leak.
Do not use any open flames like candles, matches or lighters.
Do not use telephones, cell phones, computers, appliances, doorbells or garage door openers, and do not touch any light switches or electrical outlets.
Open windows and doors only if it is possible to do so quickly and easily.
Quickly leave the house or building, taking everyone, including pets, with you.
Go to a location where you no long smell gas, and call your local natural gas utility.
Call 911 if there appears to be an immediate danger.