Gather your family members and pets and leave your house immediately. Do not stay or attempt to fix the leak yourself. If something ignites the gas, such as a lighter or a stray spark, your house could explode and you could be killed.
Call your gas utility provider and report the leak. If you do not know the number, ask a neighbor or clerk at a business to look it up for you, or call 411 for information from your cell phone and ask for the emergency number for the utility provider.
Call 911 and report the leak to your local police. The police will decide whether the leak necessitates evacuating your street and if so, they will cordon off your block until the utility provider can find and fix the leak.