Firefighter Fatalities and Injuries: The Role of Heat Stress and PPE

Study Documents Cardiovascular Risk Factors Among Firefighters

A recent research-and-development meeting hosted by the Federal Emergency Management Agency (FEMA) in Washington, DC, highlighted a large number of research projects funded by Fire Prevention and Safety Grants awarded under the Assistance to Firefighters Grant Program. The room was filled with a distinguished group of Ph.D.s and MDs that shared a common goal - making firefighting safer. And though much of this research may take several years to yield practical results, there were also presentations on completed projects that could provide valuable guidance to firefighters right now.

One of these projects, Cardiovascular and Biomechanical Responses to Firefighting and PPE, presented by Denise Smith and Gavin Horn of the University of Illinois Fire Service Institute, provides a review of the known research and new and important findings and recommendations. In plain English, this project studied how heat stress may be a common causal factor in both firefighter heart attacks (the leading cause of on-duty deaths) and slip, trip and fall accidents (the largest portion of fireground injuries).

One part of this study documented laboratory-based cardiovascular risk factors among a large cohort of firefighters and investigated the effects of different personal protective equipment (PPE) configurations on physiological and biomechanical responses to live-fire firefighting activities. Study participants included 122 male firefighters from across the state of Illinois with a wide range of firefighting experience. The group was nearly equally divided between career and volunteer firefighters. The participants were relatively young (their mean age was 29.5 years), were free of known cardiovascular disease or balance/gait impairment and were not taking medications for hypertension or high cholesterol. Participants engaged in 18 minutes of firefighting activity in a burn tower that contained live fire. Temperatures were maintained at approximately 100 degrees Fahrenheit and 170ºF at the floor and waist level, respectively. Firefighting activities included repeated work-rest cycles, with firefighters doing stair climbing, forcible entry, search and rescue, and a simulated hose pull.

Major Findings

  • A large percentage of the firefighters who participated were overweight or obese based on body mass index (BMI) measures.
  • A large percentage of these firefighters were pre-hypertensive or hypertensive.
  • Eighteen minutes of simulated firefighting activity causes significant physiological disruption including an increase of heart rate (75 beats per minute) and an increase of core temperature (1.2°F).
  • The simulated firefighting activities caused a significant increase in platelet numbers and a significant increase of platelet activation (resulting in faster clot formation).
  • Firefighting activity resulted in an increased level of coagulation (increased factor VIII activity and PF1.2) and significant changes in clot breakdown (fibrinolysis).
  • PPE configuration had no significant effect on physiological, perceptual, blood chemistry or coagulatory responses to short-term firefighting activity.
  • Donning of firefighting PPE caused significant detriments in gait and balance parameters regardless of which configuration of PPE was worn.
  • Enhanced PPE had a smaller detrimental effect on some gait parameters than the standard PPE.
  • Eighteen minutes of simulated firefighting activity had negligible further effects on gait and balance parameters compared with the effect of donning firefighting PPE.


Most importantly, this study offers recommendations for the fire service that are found in a careful review of the literature, supported by this research and aimed at reducing fatalities and injuries on the fireground. These recommendations address medical readiness for duty, physical fitness requirements, on-scene rehabilitation and hydration strategies, and personal protective equipment.

Recommendation 1 - As recommended by NFPA (National Fire Protection Association) 1582, Standard on Comprehensive Occupational Medical Program for Fire Departments, every firefighter should receive a medical evaluation before becoming a firefighter and should receive periodic medical examinations after joining the service. These exams should focus on cardiovascular health and cardiovascular risk factors and should be conducted by a physician who is familiar with the demands of firefighting.

Recommendation 2 - Extreme obesity should be considered as a disqualifying condition to safely perform firefighting duties. Obesity should be addressed in the NFPA 1582 standard.

Recommendation 3 - In recognition of the physiological strain incurred during structural firefighting, fire departments should include defined cardiovascular standards in their hiring and recruitment processes. Candidates who have uncontrolled hypertension or uncontrolled diabetes should be precluded from consideration as line firefighters until these risk factors are corrected. Firefighters who have multiple risk factors should receive additional screening and aggressive intervention given the greater risk associated with multiple risk factors.

Recommendation 4 - Firefighters must be required to adhere to lifestyle standards that have been determined to reduce the development of cardiac risk factors. These include smoking cessation, sound nutritional habits and regular exercise. These interventions and programs should be aimed at supporting individual firefighters; however, the department (and union), if appropriate may need to take action as needed to ensure compliance in cases where a firefighter does not voluntarily comply, or have the option of reassigning the firefighter to other duties. Volunteer departments must continue to pursue ways to ensure that necessary minimal requirements are met for medical readiness for duty.

Recommendation 5 - The NFPA standard on physical fitness should be universally adopted. As recommended by NFPA 1583, Standard on Health-Related Fitness Programs for Fire Department Members, all firefighters should participate in an organized physical fitness program. These physical fitness programs should emphasize cardiovascular (aerobic) fitness and include muscular fitness. Fire departments should include defined physical fitness standards in their hiring and recruitment processes. Members should be required to adhere to designated fitness programs.

Recommendation 6 - Firefighters must take personal initiative to ensure that they are fit for duty and do not present an undue cardiac risk to themselves or a liability to the firefighting mission. The voluntary fitness standards currently in place would likely be sufficient if individual firefighters understood the relevance of cardiac standards to their ability to safely and effectively perform their job requirements and acted accordingly.

Recommendation 7 - To reduce slip, trip and fall injuries, training exercises that enhance balance abilities should be added to firefighters' training protocols. Considering the detrimental effects of wearing PPE on balance and gait, these exercises are particularly important for those new to the fire service, as well as for older firefighters.

Recommendation 8 - Fire departments must adhere to the standards set forth in NFPA 1584, Standard on the Rehabilitation Process for Members During Emergency Operations and Training Exercises. Incident commanders must ensure adequate on-scene resources, either through additional mutual aid or increased staffing, to allow all personnel to rotate through rehabilitation after completing a given assignment.

Recommendation 9 - Manufacturers and fire service organizations should continue to identify and test designs, interventions and strategies directed at producing lighter or more breathable and less restrictive PPE.

The information in this article is based on the report Firefighter Fatalities and Injuries: The Role of Heat Stress and PPE published by the Firefighter Life Safety Research Center, Illinois Fire Service Institute, University of Illinois at Urbana-Champaign, July 2008. A copy of the complete report is available for download at

MARK MORDECAI is director of business development for Globe Manufacturing Co., where he is responsible for driving product development and marketing. Comments or requests for more information are welcome at