Gas Investigation


3/4/2026

What do you do if you smell gas inside or outside, or suspect a natural gas leak?

  • Leave the building or area right away
  • Do not turn on or off any switches which may be an ignition source
  • Do not use your phone in the area. The phone also could be an ignition source
  • Do not turn on or off any appliances
  • If the suspected leak is outside, do not start your car or other vehicle in the area
  • Evacuate other people & pets from the area but don’t ring the doorbell, which could be an ignition source
  • Leave the door(s) open when you leave
  • Never try to troubleshoot a leak or an appliance or try to make repairs yourself
  • Obviously, it would be a very bad idea to smoke around a suspected leak

 

Next

  • Call 911 from a safe area, away from the odor or suspected leak
  • When the firefighters arrive, meet them & brief them on the conditions
  • In addition to dispatching fire companies, Emergency Communications staff will notify Eversource to respond.
  • Firefighters may also request Inspectional Services to respond

 

Response

  • Typically, Emergency Communications will dispatch an Engine Company, Ladder Company, Rescue Company, and a Division Chief (and sometimes a Squad) to a gas incident. The response may be upgraded, depending on the situation
  • Firefighters in full PPE (personal protective equipment) will test the air via sampling meters to determine a potential explosive range
  • Depending on the conditions, they may expand the evacuation zone, establish water supplies, use water fog to control the vapors, and ventilate, while stopping the flow of gas.
  • Cambridge Police will also assist in maintaining an evacuation safety zone

 

For a compromised gas line outside, in addition to the odor, you may hear hissing or see dirt blowing out of the ground from the leak area.

 

After

  • Once the incident has been cleared and the area has been determined to be safe, you will be allowed to return
  • Most incidents are resolved quickly & safely with no extenuating circumstances

 

Remember that it is always better to be safe, instead of taking a chance with a potential ignition. If you suspect a gas leak, call 911

 

gas investigation - Rescue 1 investigating in a neighborhood residence
Rescue 1 with Ladder 1 investigating a reported odor of natural gas in a residential neighborhood
Engine 1 and Division 2 are also on scene

 

gas investigation - Rescue 1 staged for a residential investigation
Rescue 1 apparatus on scene of a residential natural gas investigation

 

a fire departent air and gas sampling meter
An "Industrial Scientific" air and gas sampling meter in use by firefighters to test the air 

 

gas investigation firefighter in full PPE (persoanl protective equipment) enterint a residence
A firefighter in full PPE (Personal Protective Equipment) making entry into a residence during a gas investigation

 

firefighters in full PPE (personal protective equipment) working at a commercial gas main investigation
Firefighters in full PPE working at a gas main break in a commercial area