Recognize a Natural Gas Leak
Be aware of signs you may see, hear or smell when there is a leak.
LookIf you see a damaged connection to a natural gas appliance, dirt/water blowing into the air, a dry patch of grass, fire or an explosion near a pipeline.
ListenIf you hear unusual sounds like hissing or whistling.
SmellIf you smell the distinctive odor of natural gas.
 Some persons may not be able to smell the odor because they have a diminished sense of smell, olfactory fatigue (normal, temporary inability to distinguish an odor after prolonged exposure to it) or because the odor is being masked or hidden by other odors that are present, such as cooking, damp, musty or chemical odors. In addition, certain pipeline and soil conditions can cause odor fade—the loss of odorant so that it is not detectable by smell.
Don’t Rely on Just Your Nose
- You have a diminished sense of smell
- You’re experiencing odor fatigue (normal, temporary inability to distinguish an odor after prolonged exposure to it)
- You have a physical condition such as a common cold, sinus condition or allergies
- You use tobacco, alcohol, drugs and certain medications
- The odor is masked or hidden by other odors that are present
- Pipe and soil conditions have caused odor fade (see below)
Sometimes physical and/or chemical processes can cause a loss of odorant in natural gas, making it undetectable by smell. Odor fade can be caused by adsorption, absorption, oxidation or any combination thereof.
Odor fade is more likely to occur in the following situations:
- In new, steel pipe that has been recently manufactured or hasn’t been used for odorized natural gas before
- In natural gas piping systems using higher gas pressure, and when natural gas flow is limited or intermittent
- In the presence of rust, mill scale, moisture, air, cutting oil, pipe thread compound, liquids, condensates and other substances
Because of the possibility of odor fade, it's important to not rely only on your sense of smell to be alerted to a natural gas leak.
For a printable copy about odor fade and safe purging practices, see our Safety Bulletin.
If you have additional questions or concerns regarding pipe conditioning or odor fade, call us at 1-800-427-2200 or contact a licensed, qualified professional.
What to Do if You Suspect a Natural Gas Leak
If you smell a natural gas odor, hear the hissing sound of gas escaping or see other signs of a leak:
- IMMEDIATELY EVACUATE the area, and from a safe location either call 911 or SoCalGas at 1-800-427-2200
- DON'T smoke, or light a match, candle or other flame.
- DON'T turn electrical appliances or lights on or off, operate motorized equipment or vehicles, or use any device that could cause a spark.