Close Calls: Explosion Blows Manhole Covers into the Air

It was determined that there was an underground 30-inch high-pressure gas main located directly below the powerline arcing on the roadway. At this point, a chief officer arrived on scene, conferred with command and then assumed command. Moments later, an explosion occurred in the underground sanitary sewer system, causing two manhole covers to launch approximately 30–40 feet into the air. 

The manhole covers were in close proximity to apparatus and first responders. An immediate evacuation was conducted for all residences along Hollywood Avenue and Hollywood Place. Once evacuations were complete, all apparatus and members retreated to a farther distance.

Upon the arrival of PSE&G, readings were taken on the roadway, underground and inside accessible structures to look for any potentially dangerous gas levels. Subsequently, the arcing wires subsided, and the incident was gradually downgraded as gas levels were determined to be safe. PSE&G de-energized power to the area to ensure the safety of area residents and pedestrians.

The fire department then extinguished the remaining fire and ensured the area was safe. The fire department operated for approximately 7½ hours.   The cause of the explosion was a natural gas buildup in the sanitary sewer from a location remote from the site. The resulting explosion escaped at the weakest point, the manhole covers.

  This incident is another stern reminder to the public as well as members of the public safety community that electrical and gas emergencies can quickly advance into potentially deadly situations. Fortunately, all area residents, firefighters and other first responders involved in this incident went home safely.

Discussion with Chief Goldfeder, Ho-Ho-Kus department leadership and others

There are several good actions to note about this run by the Ho-Ho-Kus Fire Department and its leaders. Members sized up the incident, established command, notified utilities and evacuated the immediate area, protecting the public and themselves. No one was injured. Although firefighters were in harm’s way when the manhole covers took off, no member of the public was ever at risk due to the department’s cautionary actions. Following are a few thoughts relayed to this type of response.

Utility companies: Utility companies are the experts—get them there quickly. Drill with your local utilities regularly so that your members are prepared on what to do—and what not to do—prior to the arrival of utility representatives. Have them look at your tools and equipment, specifically what you will be using prior and upon their arrival. Training should also include the utility services’ understanding of your department’s command-related policy.  

Training: Initial and ongoing annual training should be mandatory for anyone responding to these emergencies. This includes fire, law enforcement, EMS, fire-police, and any other agency that may respond.  

Laws: Determine local or state laws in relation to your department operating at gas or electrical emergencies. For example, in the case of wires down, when can you leave that scene? After you tape it off? After the utility company arrives? When you get bored? When you get another run? What if you tape it off, leave the scene, and then a civilian gets hurt, or worse, prior to you essentially “passing command” to the utility responder? Be smart and research these things now and then make sure they are a part of your policies/procedures and training—and be sure to also include your local utility emergency response leaders as a part of that. 

Prior to the utility company’s arrival on scene, there is much you can do but that should only be based upon your level of training, education and qualifications. Sometimes doing nothing other than evacuating and protecting an area, like what the Ho-Ho-Kus Fire Department did in the case, is the right thing.  

Hot zone: When establishing a hot zone for safety and barrier purposes, be cognizant of where the wires are in relation to exposures, such as walk/bike paths, roads, people, vehicles, metal fences and structures. Assume that electricity will reach those areas if additional wires come down.

Evacuation: If you are going to evacuate an area, how will you do that? How will you communicate with the evacuees initially and then throughout the situation? What’s the risk when they walk out? What about disabled folks? Where are the evacuees headed? What if it is 3 a.m.? What if it is 2 degrees outside? Do they need to evacuate or are they better off staying in their home or building? What is your department’s policy related to area evacuation? Evacuation is no simple task without policy and training.  

When appropriate, firefighters can check nearby buildings for gas and overheating electric panels and evacuate if needed.

Underground hazards: What’s underground? Firefighters all know that underground means gas—sometimes manmade and sometime natural—but the gas is down there. We have all read about workers (and firefighters) losing their lives underground when attempting to perform a rescue. With the gas comes the predictable potential of an explosion. Plan for that in training but also size-up the manholes situation related sewer drains and openings.  

Water application: In his book and related writing on “Responding to Routine Emergencies,” Chief Frank Montagna (FDNY, ret.), one of my closest mentors and friends, urges caution when applying water to these kinds of fires. There have been several incidents that resulted in injuries to firefighters who sprayed water directly into burning electric manholes. It is better to apply water after the power has been removed from the hole, but it is possible to safely apply water into a live manhole ONLY if you are properly trained to do so—and there is a need. Again, the need for training is clear.

As Chief Montagna wrote: “How can you safely respond to utility incidents without the appropriate level of training? You can't! Since you must respond regardless, make every effort to obtain training and to foster an ongoing relationship with your utility.” Nothing shocking about that advice. 

My sincere thanks to the chiefs, officers and members of the Ho-Ho-Kus Fire Department for their willingness and cooperation in sharing this event with each of you.