Last month we reviewed a gas leak and explosion that injured four firefighters from the Alpha Fire Company (AFC) in Adams County, PA. Crews responded to a gas leak, and based on evidence that there may be an occupant in the home, entered the structure to conduct a search. As the four interior firefighters searched the home, an explosion occurred, resulting in burns to the interior team members.
Last month’s account included an incident review from AFC Deputy Chief Justin Myers as well as some additional perspectives and lessons learned by the interior team. Some of the lessons learned:
- Don’t be complacent—always wear your PPE and make sure it is in excellent condition.
- Conduct a size-up and trust your gas-detection equipment; adjust tactics and PPE/SCBA levels accordingly.
- Establish a water supply plan initially. Don’t wait until the explosion to get set up at the hydrant; be ready to flow water.
- Follow established priorities and conduct a risk/benefit analysis.
Let’s now review some suggested fire department responses to gas-related emergencies, including incidents with a report of a gas leak, but no fire or explosion, as well as incidents where an explosion has already occurred. Please note that this is a suggested policy for consideration only. Each department must develop policies that are most applicable to their local resources and conditions. While these guidelines provide a response that will be applicable in the majority of situations, they do not replace local policy, law, good judgment and experience in dealing with any particular incident. The guidelines should be used whenever situations are encountered that do not clearly indicate that a different approach is required to more safely resolve the hazard.
General response points
Natural gas is much lighter than air and will usually dissipate rapidly in the outside environment. Inside buildings, however, it tends to pocket, particularly in attics and dead air spaces. The flammable limits are approximately 4–15 percent in air. Natural gas itself is nontoxic; however, it displaces oxygen and can result in asphyxiation in a confined space. Flammable gas ranges can only be determined by a combustible gas instrument. Request the dispatch of a meter (if you don't carry one) and the utility company.
Burning natural gas should not normally be extinguished, as this would change the situation from a visible to invisible hazard with explosive potential. Fires should be controlled by stopping the flow.
Response to reported gas leak
Although calls for “odor of gas,” “gas leak,” “broken gas line” can turn out to be “minor” in some cases, they have the potential to be major incidents and should therefore be approached as highly dangerous situations.
With gas company personnel on the scene of an incident, the first fire department company or unit shall establish command and provide effective communication between agencies. Gas company personnel shall be responsible for locating and eliminating leak sources. Gas company personnel and the fire department shall obtain a sufficient number of gas concentration readings, using their combustible gas indicators for Command to size up the hazard and take appropriate action.
In all cases, fire department units shall take whatever actions are necessary to provide for life (primary) and property (secondary, as applicable) safety.
A Hazardous Materials Plan should be developed and used as a basic guide for these incidents. A minimum number of full PPE personnel should be allowed to enter the area to size-up the situation while any additional units stage in a location out of the potentially dangerous zone. Think—don't put all your eggs in one basket.
Attempt to locate the source of the gas and any shutoff devices available. For gas leak situations within a building where the source of the leak is unknown or uncontrolled, the gas supply shall be shut off at the meter. Command shall ensure the meter is red-tagged and locked off until repairs are completed. This is most easily accomplished with the cooperation of the gas supplier at the scene.
If there is any indication of gas accumulating within a building, evacuate civilians from the structure and control ignition sources. Check for explosive concentrations with a combustible gas indicator if there is any suspicion of accumulation within a structure. Shut off electrical power from an outside breaker. Ventilate by opening windows and using explosion proof blowers to pressurize as necessary.
If gas company personnel must excavate to shut off a leak, provide standby protection with a charged line and firefighters in full protective equipment and SCBA.
Response to explosion
The first-due companies arriving at the scene of a structural explosion must consider natural gas as a possible cause. Additional companies should stage away from the scene so that all companies are not in the hot zone at the same time. All members operating must be in full head-to-toe PPE and on air.
Explosions have occurred in structures that were not served by natural gas. Underground leaks may permit gas to travel considerable distances before entering a structure through the foundation, around pipes or through void spaces. In these circumstances, the cause of the explosion may be difficult to determine.
Until it can be determined by command that the area is safe from the danger of further explosions, evacuate all civilians and keep the number of fire department and/or other emergency personnel (e.g., gas company personnel) in the area to the minimum number necessary to stabilize the situation. Take a worst-case scenario point of view. Command may choose to minimize the risk by only allowing the first-due company to perform a size-up and evaluation while staging other companies. By limiting the number of companies exposed, if there were an explosion, these other companies would potentially be in the best position to rescue those companies in trouble.
Do not rely on gas odor. Use combustible gas indicators to check all suspected areas. Both gas company personnel and your department should have combustible gas meters for this purpose. A fire company responding without meters is at great risk and should stage and await the correct equipment.
Use meters to systematically check all areas. Start outside of the area of the explosion, and move into the area until readings indicate detectable concentration. Map the readings for the affected area.
If a gas concentration is encountered inside, adjacent to or underneath any building, secure all possible sources of ignition in the affected area. Have the electric company or a qualified crew cut electricity from outside the affected area to avoid arcing. Where gas is found, ventilate buildings with explosion-proof equipment.
The use of ground probes is essential to evaluate potential underground leaks. When gas company personnel are on the scene, ground probe readings and locations must be coordinated. Time, location and concentration should be recorded for each probe, and subsequent readings should be taken from the same holes when possible.
Command shall ensure interaction between gas company personnel and the fire department. Gas company personnel are responsible for locating and eliminating leaks in the gas system. As industry specialists, they can provide Command with valuable assistance in the effective handling of these incidents. In most cases, a company officer with a radio will be required to supervise specific divisions during on-site operations.
Command must ensure the safety and stability of the structure. If further collapse is possible, a trench/heavy rescue team should be called to provide shoring, cribbing or other means of stabilizing the structure.
Personnel safety
All personnel who must operate in the vicinity of a known or suspected gas leak shall wear full protective clothing with SCBAs. Personnel working in a suspected ignitable atmosphere (e.g., attempting to shut off a gas line) shall use SCBA and shall be protected by a manned hoseline. The number of exposed personnel will be kept to an absolute minimum at all times.
Determination of hot, warm (both hazardous) and cold zones (potentially hazardous based upon debris field, etc.) must be established. The hot zone shall be established and maintained around any suspected gas leak and "fire line" tape should be used to identify the Limited Access Zone when necessary. Command, control and accountability, as in all incidents, are a critical factor in achieving success.
In conclusion
In the mid-1970s, I responded as a part of a first-alarm assignment to a report of a “large propane gas tank leaking.” When we arrived, we found a 200-lb. tank on a work site, leaking. We were unable to immediately control the leak. Keep in mind we were wearing our cotton duck coats, orange fireball gloves and “puff” gas meter; we left the SCBAs in the boxes for this run, as we did on almost every run.
We were ordered to move the tank, while it was leaking, and place it on the tailboard of our apparatus and hold on to it—tightly. The plan was to quickly transport it on the tailboard to a field, away from the public. (For you fire service history buffs, it was on that day that our crew on Rescue 30 developed the now popular term “WTF.”) Fortunately, our captain was able to convince the chief in charge that we were better off NOT doing that, but rather managing the situation through evacuation and hose stream dissipation from the scene.
Unfortunately, gas leaks are not always taken seriously due to training issues and because, in most cases, they turn out to be minor incidents. But that kind of response by any of us is a huge gamble—one we don't have a right to take! We are responsible for our own people and the public, so we must go above and beyond based upon the possibility of the incident going wrong. Pay attention to history!
Years ago we didn't have the training opportunities we do today. Not taking advantage of these opportunities is failing to meet our sworn duty of taking care of the public and each other. Gas leaks of any kind require our full attention and response as if something could go wrong at anytime. You knew that, right? Good. We are in good shape.
Thanks to the training and leadership at the Alpha Fire Company, this Firehouse Close Call was not anywhere as bad as it could have been. Once again, a great opportunity to learn from the brothers and sisters who have been there and done that.
Billy Goldfeder
BILLY GOLDFEDER, EFO, who is a Firehouse contributing editor, has been a firefighter since 1973 and a chief officer since 1982. He is deputy fire chief of the Loveland-Symmes Fire Department in Ohio, which is an ISO Class 1, CPSE and CAAS-accredited department. Goldfeder has served on numerous NFPA and International Association of Fire Chiefs (IAFC) committees. He is on the board of directors of the IAFC Safety, Health and Survival Section and the National Fallen Firefighters Foundation.
