By Patrick L. Brown

It seems every time a firefighting periodical is published, someone is writing about stopping firefighter fatalities. Various recommendations have been made in the hopes of saving one firefighter’s life. Annually, 50 percent of firefighters killed in the line of duty die of stress-related injuries, namely cerebrovascular accidents (CVA/stroke) and heart attacks. Many studies have examined the causes of these deaths and some recommendations have been made, but are these conclusions all-inclusive?

One study came to the conclusion that firefighters are less fit today than our forefathers were. The author recommended a better diet and more fitness training for firefighters. Both recommendations are vital, but are we less fit? Are inadequate fitness and poor diet the only causes of these stress-related deaths?

Another study said fires today are hotter than those of the past. This increased heat is putting greater stress on today’s firefighters; this conclusion cannot be disputed. Today’s fires, fueled by synthetic materials, burn hotter than natural fiber fires of the past. Additionally, today’s tightly constructed buildings hold the products of this combustion better. This combination creates a hotter environment for working firefighters. Is this the sole cause of stress-related deaths?

Another study contended that firefighters are overheating and recommended wearing ice vests under bunker gear to help dissipate the heat created by working in fire conditions. This vest may help, but will the benefit be great enough to overcome the increased exertion caused by carrying more restricting weight?

What is causing all of this heat? An area that demands attention by the fire service is bunker gear and its association with firefighter heat stress.

Nationally, full bunker gear is the standard firefighter gear and is recommended by the National Fire Protection Association (NFPA). This gear has existed in various forms for decades; it became widely used by the fire services in the 1980s. Presumably, the goal of the gear was to protect firefighters from burns; it seems obvious that the goal was achieved. Firefighter burn injuries are down, but at what cost? Annually, more firefighter deaths are related to stress-related issues. These are only the deaths! How many firefighters sustain permanent, debilitating, stress-related injuries annually? How many firefighters pension off because they can no longer function as firefighters after suffering strokes or heart attacks?

Present-day bunker gear must be considered as possibly part of the problem. The insulation in the gear that works so well at keeping the heat of combustion out also keeps body heat in. Normally, as the body heats up, vessels dilate to cool the blood. Additionally, the body perspires to get moisture onto the skin. Wind evaporates the moisture and the body starts to cool. Bunker gear, which virtually encapsulates the firefighter, prevents the body’s natural defense mechanisms from working. Bunker gear does not readily allow perspiration out, thus preventing evaporation and cooling. The body continues to heat up and keeps trying to get blood out to the periphery to help it cool. This affects blood return to the heart. Perspiring, which is supposed to help cool the body, eventually starts to worsen the situation. The body perspires so much that dehydration develops. Dehydration affects blood return to the heart and leads to electrolyte imbalances. The heart responds to the decreased blood flow by pumping harder and faster, thus straining the heart. Electrolyte imbalances lead to many problems including muscle cramps, mental status changes, and cardiac dysrhythmias. Another important fact to remember is elevated temperatures alone can be very damaging to the body. Brain damage can occur when the body temperature reaches or exceeds 106°F.

Bunker gear is also cumbersome to work in. Firefighters have to work harder just to do basic skills. Walking up stairs and swinging tools are harder to do while in bunker gear. Exertion stresses our cardiovascular system, causing the heart to beat faster, which increases oxygen demand and creates additional heat. The retained perspiration within the bunker gear becomes heated up and accelerates the heating process. The body responds by sweating until it cannot sweat any longer. The heart responds by continuously beating faster, trying to get blood out to the periphery to cool off and feed the working muscles. Body fluids are lost through perspiration and labored breathing. Blood return to the heart decreases. The heart responds by beating faster and harder. Blood pressure begins to fall. If this process is not reversed, heat stroke, heart attacks, and strokes occur. To stop this process, the firefighter must stop all activity, open up the gear (especially the pants) to allow the cooling process to take place, and then begin rehydrating. How long can a firefighter work before this cascading condition leads to a catastrophic outcome? I don’t think anyone knows for certain what the exact time frame is.

In my opinion, bunker gear cannot be overlooked when discussing firefighter stress-related injuries and deaths. More research is essential, and bunker gear changes are needed; it must be lighter, provide more unrestricted mobility, prevent moisture from entering yet allow moisture from the inside out, be cooler, and provide more ventilation. Maybe the gear overall offers too much thermal protection. Will less thermal protection offer adequate protection against burns yet be lighter, breathe better, and provide more mobility? Could other materials better suit our needs? Bunker gear does a good job at protecting firefighters from burns, but there must be a happy medium. Heat stress can be fatal to firefighters.

The fire service has evolved over the centuries. We have progressed from wood water mains and bucket brigades to motorized pumpers with high-tech, low-friction loss hose; from iron lunged, smoke-eater firefighters to wearing SCBAs that protect us from lung disease; from wearing basic pants and coats with a leather helmet to our present-day bunker gear. All of these changes have been made to protect us and allow us to do our job better. The next step in the progression of bunker gear needs to happen. We cannot sit idly by while heat stress impacts the health and well-being of firefighters.


1. “Hot under the turnout,” Denise L. Smith, Ph.D., visiting research fellow, Illinois Fire Service Institute, University of Illinois.

2. “Firefighter Deaths by Cause and Nature of Injury- 2005,” National Fire Protection Association (NFPA) Fire Incident Data Organization.

3. “Firefighter Fatalities in the United States- 2005,”NFPA.

4. “Health and Safety Guidelines for Firefighter Training,” University of Maryland Center for Firefighter Safety Research and Development.

Patrick L. Brown is a firefighter and paramedic with the Chicago (IL) Fire Department. He is a state-certified firefighter III, fire officer I, and instructor II, as well as a licensed registered nurse specializing in emergency medicine and trauma.

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