Fast Find

Suspect a Leak - What To Do

Gas Leak with Nose

How can I recognize a gas leak?


The natural gas industry has an excellent safety record, and Somerville Gas works very hard to keep it that way. However, it is important that our customers and community residents know what to do in the unlikely event of a natural gas leak. You can detect the presence of natural gas a number of ways.

  • SMELL: A distinctive "rotten egg" odor added to make natural gas detectable
  • LISTEN: An unusual hissing sound near gas appliances or a blowing sound near gas lines
  • LOOK: Blowing dirt, bubbling creeks or ponds, dry spots in moist areas or dead plants surrounded by green live plants near gas lines

What should I do if I suspect a gas leak?

If you suspect a natural gas leak in your home or outside, follow these safety steps:

  • LEAVE the area IMMEDIATELY and tell others to leave too.
  • CALL 911 or Somerville gas department at 1-901-465-9500 during normal business hours or the after-hours emergency call phone at (901)-387-9005 or after normal business hours.
  •  DO NOT turn any lights on or off, smoke or use a cell phone, or operate any vehicle or equipment that could cause sparks.
  • DO NOT attempt to turn natural gas valves on or off.

Somerville will send a trained service technician immediately to investigate any emergency leak call.


Is it always possible to detect leaking gas by its odor?

The sense of smell for most people is a highly reliable indicator of a natural gas release. However, a continued exposure to mercaptan, the most typical odorant added to natural gas, can desensitize your sense of smell. Therefore, if you ever smell leaking natural gas, do not wait! Leave the premises immediately and call Somerville Gas or 911. 

If you suffer from anosmia, olfactory fatigue or recurrent ailments, such as colds, sinus conditions or allergies, you might have a diminished capability to detect a natural gas leak. Using tobacco, alcohol, medications or narcotics can lessen your ability to smell odorized gas. Pungent odors from chemicals in some lines of work and off-gassing of new building materials also can mask the odor of mercaptan. 

If a medical condition or your lifestyle might prevent you from smelling natural gas, use all your senses—smell, listen and look—for telltale signs of a leak. 

What is carbon monoxide?

Carbon monoxide, often referred to as CO, is a poisonous gas that is odorless, colorless, tasteless, and non-irritating. It is formed by the incomplete combustion of almost any material, but particularly hydrocarbon fuels such as gasoline, kerosene, coal, propane, natural gas, wood, charcoal, diesel fuel and heating oil.

When CO is inhaled, it combines with the body's blood and prevents it from absorbing oxygen. A person exposed to high levels of CO may complain of dizziness, headache, nausea, sleepiness or other flu-like symptoms without fever.

Stationary vehicles are the most common source of CO poisoning while natural gas appliances account for a small percentage of all CO poisonings. The primary cause of CO problems associated with natural gas appliances is space heating equipment in which vents and chimneys are not properly installed or maintained. Other causes include misuse of appliances such as improper use of ranges and ovens for space heating.

How do I prevent exposure to carbon monoxide?

Do not operate gasoline-powered motors or use charcoal grills in enclosed spaces, such as an attached garage.

Provide adequate ventilation when using a wood stove or fireplace, and be sure it is in good working condition.

Be certain that all flame-producing appliances are properly installed, adjusted and operated. Check vented appliances periodically to be sure that the vent pipe has a proper rise and is not blocked by bird nests or other debris. The vent pipe should have an approved vent cap securely attached at the end.

Special care must be taken with gas space heaters because many are installed unvented. It is especially important to make sure than an adequate supply of fresh air is available to ensure proper combustion. Proper combustion is normally indicated by the presence of a clear, blue flame. A small amount of yellow or orange is normal and is caused by flecks of dust in the air.

Carbon monoxide detectors are commercially available and are relatively inexpensive. The best precaution, of course, is to have an annual inspection by a qualified professional. We encourage you to install CO detectors that have been approved by a national testing laboratory.