The Hazards We Face


In our last installment, we finished looking at the safety side of our hazard vs. safety model. We went through the details of adequate staffing, operational hardware, safety standard operating procedures, and personal protective equipment (PPE) and finished up with a discussion of incident command by going over the eight standard functions of command. The model is a critical part of the initial and ongoing size-up process. These items make up the basic safety system we use on every level to protect our firefighters working in the hazard zone.

Fire companies operating on the task level must evaluate the ability of all the safety system elements “they have on” (literally, in the case of PPE) to directly protect them from the level of hazard present. They must also forecast the future hazard level of where they will be working as the incident evolves—what’s next/next/next? Sector/division/group tactical level bosses are the decentralized eyes and ears of the incident commander (IC). They must maintain an awareness of the safety/hazard balance in their assigned area and function and must always account for and move the troops forward when the safety side is bigger than the hazard side. Conversely, they must move the workers away from the hazard zone when the hazards are more powerful than the safety system components. The IC must use the eight standard command functions to determine and manage the overall offensive/defensive strategy for the entire incident—again, based on an incidentwide hazard/safety comparison. 


Opposite from the safety system on the other end of the model are the hazards we typically face when we are fighting fires in buildings. They are structural collapse, thermal insult, and toxic insult. Although each hazard has its own set of characteristics, generally all three are present and are quickly changing and unique to each incident. Determining the ongoing proportion of hazards present in each incident is a big part of size-up. Their presence when all three are together creates very bad synergy that increases the overall level of risk to a more immediately severe point than if they were there separately (even though they are bad enough by themselves).

We must expect to encounter each hazard every time (skip the surprise!) and be prepared and able to position and protect ourselves from that hazard using our safety system. The continual rant while we are covering this subject is that our basic survival objective is to connect our safety capability to the level of those three hazards. Doing this becomes the foundation for our making an intentional ongoing, continually updated tactical decision about where we can go and what we can do on the fireground.

The three basic fireground hazards we face are timeless and have been with us since the beginning of our service. Our members have historically been and currently still are injured and killed when fire-weakened structures collapse on them or under them. When structures are burning, the fire reduces the integrity of how the building is “held together.” Structures are built (actually connected) using all sorts of fasteners: nails, plates, clips, gussets, structural connections, and so on. Fire weakens these connections and when gravity overcomes that structural weakness, kaboom!: That part of the building or the whole building collapses. Professor Francis L. Brannigan taught us, “Gravity is the enemy.” Virtually all ordinary constructed buildings will collapse if they burn long enough. 

Structural Collapse 

A huge firefighting safety problem is that the only real defense against structural collapse is to prevent it by putting out the fire. We don’t show up with any capability to prop the building up while it is burning or any piece of equipment that affords collapse protection. Perhaps we should develop sturdy little interior “tanks” in which we can ride while inside the fire-weakened hazard zone and scoff at collapse. A critical capability for us is to be able to accurately evaluate fire and structural conditions and accurately and pessimistically predict when the building will collapse if the fire continues.

This collapse size-up and timing estimation of when collapse will occur create the framework for command and control of the duration and details of offensive interior operations: when we can go inside and when we must get out. This time of collapse estimation is a critical IC capability that comes from study, reflection, and actual firefighting—fire command experience. That capability to decide if it’s a go/no-go involves science, art, and intuition. We have heard that capability described as having “Gypsy blood”: “I don’t know how he knew… he just knew (when to get us out).”

A basic and critical safety procedure is to get away from any significant collapse of part or all of the structure because such collapse will instantly crush our head, organs, and limbs. There is no tactical, operational defense against a structural collapse except to be outside the collapse zone when it happens. When you are under collapse debris, you cannot get it off you—there is no such thing as “collapse decon.” 

Thermal Insult 

Thermal insult is another basic hazard we have always faced and is really the traditional reason we are in business. The fire service was originally formed to protect the community from fire—i.e., thermal insult. We have developed our service to be the fire control specialists for the people and places we protect. Although we have expanded the use of our firefighting resources in recent times to deliver medical and special operations services, our basic, historic mission is to quickly respond to and extinguish unfriendly fire.

This firefighting mission necessarily requires our members to actively, physically, and directly engage fires. The old adage “We run in when everybody else is running out” describes the very typical action we take. There is no automation. Virtually all rescue and firefighting, particularly offensive firefighting (where we run in), is done by hand: conducting physical primary searches, using mobile attack lines, and employing tool-induced building manipulation. The rescue-fire control outcome is determined by the effectiveness of the firefighters who put their personal anatomy and physiology (A&P) in between Mrs. Smith and the fire.

The act of firefighting requires that the system (read bosses) must somehow protect the actors from the thermal insult they will encounter doing their job. This is where the safety system uses the elements we have been discussing to create the operational capability for the workers to enter the hazard zone, stay there long enough to complete the tactical priorities, and then to be able to safely exit the hazard zone—we are now calling this a “round trip.” The challenge we face doing this consistently is that all the parts of the safety system have their own capabilities and limitations. Very simply, when the level of hazards exceeds the related capability, that part of the safety system must be increased—more firefighters, water, hardware, and supervision/command—or the strategy must be adjusted.

Being able to keep safety ahead of the hazard level is the reason our model is on a teeter-totter that goes up and down on both ends based on the comparative levels of each end. This makes operating and managing the balance both exciting and unforgiving because if we get it wrong, the firefighters operating in the hazard zone must physically absorb the effect of the “bad” balance—certainly bad for the firefighter. This balance reality is timeless and true and applies to all three basic hazards: collapse and thermal and toxic insult.

A big problem with thermal insult revolves around the built-in capability of PPE protection. That equipment affords the most intimate protection for hazard zone workers; they are literally wearing it on their bodies. The degree of thermal protection performance (TPP) is what it is and no more. We can and many times do increase the attack force by calling for more troops, water, tools, trucks, command, and drinking fluids. But we can’t call for more TPP because the fire is getting bigger/hotter. We also cannot call in more firefighters with a higher level of inherent heat tolerance. That level of tolerance was set at the factory. When we reach the TPP and firefighter anatomy a physiological limit, we must quickly and decisively move those troops to “TPP/A&P okay” positions. 

Toxic Insult 

Toxic insult is a lot like thermal insult, only we use self-contained breathing apparatus (SCBA) for toxic protection for firefighters. These units are part of the PPE ensemble. Their basic limitation is the duration of the air supply they provide. Firefighters cannot survive working in the products of combustion without continuous respiratory protection. The products of combustion are heat, flame, smoke, and fire gases. They are all bad, awful, and deadly. Some fire products are so toxic that they will kill us with two breaths. Nothing alive and very little physical material can survive direct fire contact, and indirect fire contact (exposure) will soon become direct. Regular fire behavior/spread will naturally radiate, convect, and conduct itself onto anything and anybody it can reach.

When firefighters don their SCBA and go into a hazard zone that is charged with the products of combustion, their life expectancy is directly connected to the amount of air in their tank. We do not consciously engage this grim reality very much, and we do routinely and appropriately conduct and survive interior operations, so going into an interior hazard zone doesn’t seem like a big deal to us. By doing this over and over, going into a hazard zone becomes “just another day at the office.”

When we do thoughtfully engage the reality of toxic insult, it creates a higher level of operational caution and causes us to do a quicker, better job of resource backup (note I used the word caution, not timidity). Thermal and toxic fire conditions injure and kill firefighters when they are operating within those two conditions and for whatever reason become lost or trapped in the hazard zone. When this very common line-of-duty-death cause occurs, if the firefighter is not quickly rescued he will run out of air in the SCBA and will be breathing toxic air. Many times fire conditions around that firefighter worsen, and then there is an increased toxic and thermal whammy. If the firefighter is not located and removed and fire growth continues, the structure may collapse on him. This is the absolute worst-case scenario.

This is really depressing stuff. I am certain that you have come to the very correct conclusion that has been running through the series: Most of it is also a no-brainer. Like a lot of no-brainers, the reality is simple, basic, and very painful when we don’t pay attention. I believe that it is useful to review and revisit the safety system vs. hazards process because an imbalance of the model is still injuring and killing us.

The most experienced, capable, street-smart fire departments in this country that operate with more command and control resources and operational capability and skill today still experience structural collapse that kills their firefighters. They also sadly and routinely transmit Maydays under desperate conditions when they have lost, trapped, and missing firefighters who are being actively assassinated by toxic and thermal conditions in the hazard zone. Virtually every one of those situations involves the hazards outperforming the safety system. These sad situations will continue until we make the safety model our way of operational life—every time and every place.

Retired Chief ALAN BUNACINI is a fire service author and speaker. He and his sons own the quarterly fire service magazine and the Blue Card hazard zone training and certification system. He can be reached at

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