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Firefighter Trainee Dies From Hyperthermia After Live-Fire 

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Executive Summary

On May 31, 2008, a 28-year-old male volunteer firefighter trainee (“Trainee A”) participated in livefire training at the State’s Fire Service Training Professional Skills Center (PSC). The weather was hot 

and humid with a heat index of 97° Fahrenheit (F). While wearing full bunker gear with self-contained 

breathing apparatus (SCBA), Trainee A completed the following rotations over 10 hours with periods 

of rest and rehabilitation of varying duration between rotations: interior burn building fire suppression, 

hidden wall fire, fire extinguisher, pallet/dumpster fire, and car fire. The Trainee was reportedly “hot 

and sweaty.” Upon completion of the training, the Trainee entered the apparatus building to change 

clothes. A short time later, an instructor found the Trainee unresponsive in the restroom. 9-1-1 was 

called as instructors began cardiopulmonary resuscitation (CPR). An ambulance provided advanced 

life support as the Trainee was transported to the hospital’s Emergency Department (ED). 

Resuscitation efforts continued in the ED, but these efforts were unsuccessful and the Trainee was 

pronounced dead. The Trainee’s core body temperature was not measured during rehab or in the ED, 

but, based on the clinical scenario, the death certificate and autopsy completed by the Medical 

Examiner listed “hyperthermia” as the cause of death, with “hypertensive atherosclerotic 

cardiovascular disease” and “obesity” as other significant medical conditions. The findings of the 

NIOSH investigation support this conclusion. 

NIOSH investigators offer the following recommendations to the State facility and the Trainee’s fire 

department to prevent similar incidents and to address general safety and health issues.

Key Recommendations • Conduct live-fire training exercises consistent with National Fire Protection Association

(NFPA) 1403, Standard on Live-fire Training Evolutions

• Formulate and institute a heat stress program, incorporating elements before, during, and after

all training courses

• Institute a rehabilitation (rehab) program consistent with NFPA 1584, Standard on the

Rehabilitation Process for Members During Emergency Operations and Training Exercises

• Provide medical evaluations to fire fighters and a medical oversight program consistent with

NFPA 1582, Standard on Comprehensive Occupational Medical Program for Fire

Departments

• Phase in a comprehensive wellness and fitness program for fire fighters consistent with the

IAFF/IAFC Wellness Fitness Initiative and NFPA 1583, Standard on Health-Related Fitness

Programs for Fire Department Members

• Perform an annual physical performance (physical ability) evaluation as listed in NFPA 1500,

Standard on Fire Department Occupational Safety and Health Program

• Provide fire fighters with medical clearance examinations to evaluate their ability to wear a SCBA

• Ensure standard treatment guidelines are followed for firefighters who may have a heat-related

illness
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The National Institute for Occupational Safety and Health (NIOSH), an institute within the Centers for Disease Control and Prevention (CDC), is the 

federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. In 1998, Congress 

appropriated funds to NIOSH to conduct a fire fighter initiative that resulted in the NIOSH Fire Fighter Fatality Investigation and Prevention Program, 

which examines line-of-duty deaths or on-duty deaths of fire fighters to assist fire departments, fire fighters, the fire service, and others to prevent similar fire 

fighter deaths in the future. The agency does not enforce compliance with state or federal occupational safety and health standards and does not determine 

fault or assign blame. Participation of fire departments and individuals in NIOSH investigations is voluntary. Under its program, NIOSH investigators 

interview persons with knowledge of the incident who agree to be interviewed and review available records to develop a description of the conditions and 

circumstances leading to the death(s). Interviewees are not asked to sign sworn statements and interviews are not recorded. The agency's reports do not 

name the victim, the fire department or those interviewed. The NIOSH report's summary of the conditions and circumstances surrounding the fatalityis 

intended to provide context to the agency's recommendations and is not intended to be definitive for purposes of determining any claim or benefit. 

For further information, visit the program website at www.cdc.gov/niosh/fire or call toll free 1-800-CDC-INFO (1-800-232-4636).
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Introduction 

On May 31, 2008, a 28-year-old male volunteer fire fighter trainee (referred to as “Trainee A” in this 

report) died due to hyperthermia after strenuous live-fire training conducted in hot and humid 

environmental conditions. The National Institute for Occupational Safety and Health (NIOSH) was 

notified of this fatality on June 4, 2008 by the United States Fire Administration. NIOSH contacted the 

affected fire department on June 16, 2008 to obtain further information, and on July 16, 2008 to initiate 

the investigation. On August 4, 2008, a Safety and Occupational Health Specialist from the NIOSH 

Fire Fighter Fatality Investigation Team conducted an on-site investigation of the incident.

During the investigation, NIOSH personnel interviewed the following people: 

 Fire Chief of the Volunteer Fire Department

 Manager of the State Fire Fighter Certifications and Volunteer Programs

 State Fire Service Training PSC coordinator

 State Fire Service Training instructors

 State Fire Fighter Fatality Investigation Team

 Crew members of Trainee A

 Trainee A’s spouse and family

NIOSH personnel reviewed the following documents: 

 State Fire Service Training incident reports

 State Fire Fighter Fatality Investigation Team report

 Crew members’ witness statements

 Fire department 2007 annual response report

 Ambulance service emergency medical report

 Local hospital ED record

 Autopsy report

 Primary care physician records

State’s Fire Service Training Professional Skills Center (PSC)

The PSC is the State’s host site for fire fighter academies and various live-burn training sessions. Livefire training is required for Fire Fighter I (FFI) certification. Live-fire exercises at the PSC consist of 

interior and exterior fire suppression. 

The interior live-fire rotation takes place in the burn building (Photo 1). During the morning, trainees 

are led through the building on a walkthrough and then observe the instructors performing a live-fire 

evolution. In the afternoon, trainees conduct the interior live-fire suppression evolutions. 

There are 5 exterior live-fire rotations conducted in both the morning and afternoon sessions. The 

exterior rotations consisted of hidden wall fire (Photo 2), fire extinguisher (Photo 3), pallet/dumpster 
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fire (Photo 4), and car fire (Photo 4). Appendix A has a complete description of each training exercise. 

As with the interior rotation, trainees are led on a walkthrough of the prop prior to the live-fire 

evolution. 

Personal Protective Equipment (PPE) is worn on all rotations. PPE consists of boots, turnout gear, 

gloves, helmet, and SCBA. While the SCBA must be worn on all rotations, only the trainees on nozzle 

operation are “on air.” The other tasks are performed off-air.

There is a shaded rehab pavilion located near the burn building (Photo 5). Between rotations trainees 

visit the designated rehab stations during which time they could doff their turnout gear, drink fluids, 

and rest. However, sometimes there was not enough time between rotations to receive rehab at the 

rehab station. 

Instructors 

There were 7 instructors and 5 staff members present during this training session. Instructors and staff 

members filled the roles of command, ignition officer and assistants, safety officer, support sector 

(water supply and medical), fire attack sector, rapid intervention team (RIT) sector, and rehab sector. 

All instructors and staff follow the incident command system and are equipped with portable radios. 

Appendix B provides a listing of the responsibilities and qualifications of the instructors.

Prior Training Requirements

Prior to participating in the live-fire training, trainees are required to attend a 6-week FFI training 

program and demonstrate skills in safety, fire behavior, portable extinguishers, PPE, ladders, fire hose, 

hose appliances, fire streams, overhaul, water supply, ventilation, and forcible entry. Student training 

must be verified by their respective fire chief who signs a training verification form maintained at each 

local fire department. 

Weather Conditions

The weather on May 31 was hot and humid. Temperature measurements were made at the nearby 

regional airport by National Oceanic and Atmospheric Administration (NOAA) and are listed in Table 

1. No black globe reading was available to account for the sun’s or the fire’s radiant heat, therefore a 

wet bulb globe temperature (WBGT) could only be estimated [ABM 2010; Lugo-Amador et al. 2004]. 

Investigation 

On May 31, 2008, Trainee A, and 24 other trainees, arrived at the State PSC at about 0700 hours to 

participate in a live-burn training class. Upon arrival, trainees completed course registrations forms. On 

the back page of the registration form, trainees were asked to identify any health concerns, medical 

history, or medications in case first aid or medical treatment was needed. The Trainee listed “ulcerative 

colitis,” but did not mention that he had suffered “flare-ups” over the last 2 days. The lead instructor 

(also known as the instructor-in-charge) reviewed all the registration forms and noted the reported 

medical problems. 
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At 0800 hours, the lead instructor and PSC coordinator introduced the training instructors and staff and 

began their safety briefing. They orientated the trainees to the: 

• facility [restrooms, designated smoking area, rehab areas, hazardous material (fuels) locations, 

material safety data sheets, fire alarms, exits, and mustering locations]; 

• PSC policies and procedures [incident command, walkthroughs prior to evolutions, PPE, 

rehabilitation, roll call, and accountability (use of colored and numbered accountability tags, 

buddy teams of 2 trainees, and rotation board)]; 

• the day’s scheduled rotations (Appendix A). 

During the safety briefing, hydration was emphasized. To prevent dehydration, the PSC coordinator 

reminded the trainees to drink the liquids provided at 3 locations: (1) in the shaded rehab pavilion near 

the burn building, (2) near the car/dumpster fire prop, and (3) in the apparatus bay near the classroom.

The lead instructor completed the compliance plan for NFPA 1403, Standard on Live-Fire Training

Evolutions [NFPA 2007]. The 25 trainees were then divided into 3 groups of 6 trainees and a fourth 

group of 7 trainees. Trainee A was assigned to this last group, also known as the Blue group. After a 

10-minute break, the groups reported to their respective props. Appendix C lists the timeline and 

sequence of the Blue group’s rotations. 

The Blue group’s first assignment was rehab at the pavilion (Photo 5). During this rehab assignment, 

several trainees, including Trainee A, were asked to fluff the excelsior. While fluffing for about 

20 minutes Trainee A wore his boots, bunker pants, gloves, and helmet. Trainee A then returned to 

rehab for the remaining 20–30 minutes of the rotation. 

At approximately 1000 hours, the Blue group began their walkthrough and observation of the burn 

building rotation in full PPE. The rotation lasted about 50 minutes and the group had 10 minutes to get 

to their next rotation (Hidden Wall Fire). This 10-minute break did not allow enough time for the 

group to walk to the rehab station and then to the Hidden Wall prop. During the hidden wall fire 

exercise, a Blue group trainee (“Trainee B”) suffered heat exhaustion at approximately 1100 hours. 

The Blue group instructor summoned the lead instructor (a certified paramedic) who also was the 

training medical officer. The lead instructor/medical officer obtained the medical kit, drove to the 

Trainee B’s location, and treated him. The Trainee B’s vital signs were taken with the following 

results: blood pressure of 130/80 millimeters of mercury (mmHg), a heart rate of 140 beats per minute, 

a respiratory rate of 22 breaths per minute, and his blood sugar level was 123. He was given oxygen 

and an ambulance was requested through 9-1-1. Vital signs taken a second time revealed a blood 

pressure of 130/100 mmHg, heart rate of 97 beats per minute, and a respiratory rate of 18 breaths per 

minute. The ambulance arrived and transported Trainee B to the local hospital’s ED where he was 

treated for dehydration and released approximately 2 hours later. 

While treating Trainee B, a second Blue group trainee (“Trainee C”) suffered heat exhaustion at 

approximately 1120 hours. Trainee C’s vital signs were within the normal range and he seemed to be 

improving. After a period of removal from training, including time spent in front of a cooling fan, 

Trainee C returned to the Blue group. 

The remaining members of the Blue group completed the hidden wall fire and the fire extinguisher 

rotation. These two rotations were the only actual live-fire evolutions during the morning hours. There 
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was a short break of 5–10 minutes prior to the next rotation (pallet/dumpster fire and car fire). During 

this short break, trainees were able to get a drink at the un-shaded rehab station but did not have 

enough time to remove bunker gear or cool down completely. After completing the walkthroughs of 

the pallet/dumpster/car fire props, the Blue group joined the other groups for their lunch break at 

approximately 1220 hours. 

After removing their bunker gear, Trainee A called his wife to bring bottles of Gatorade® to the PSC. 

Trainee A had lunch in the shade near the apparatus building, eating a sandwich, and drinking a 

32-ounce bottle of Gatorade®. Everyone that had contact with Trainee A during the morning rotations 

or lunch reported that he was happy, enthusiastic and ready to keep going. Although his classmates and 

staff noted he was sweating profusely, he did not appear to be in any distress and reported feeling able 

to continue with the training day. 

Throughout the day, trainees were encouraged to notify an instructor when they needed a break. 

Instructors watched the trainees for signs of fatigue or heat-related illness (HRI) and granted rest 

breaks when requested. However, many instructors reported difficulty seeing the trainee’s faces 

through the SCBA facepieces, thus they could not adequately assess the trainee’s condition. One 

trainee from the Blue group admitted to being so hot and tired that, once he completed his rotation on 

the nozzle and had moved to the RIT, removed his facepiece and opened his coat to cool down. He 

believed he “got in trouble” for this action and responded that he was, “too hot and they could just kick 

him out if they didn’t like it.” An instructor reported that at least two trainees came to their RIT 

assignment and appeared to need rest. The instructor allowed them to remove their facepieces and open 

their coats to cool down, although this was not normal procedure.

Following the 70-minute lunch break, the groups reassembled at 1330 hours. Once again, the Blue 

group was assigned to rehab in the pavilion, and Trainee A volunteered to fluff the excelsior. 

Following their rehab assignment, the group progressed to the burn building for their interior live-burn 

evolution. 

The interior live-burn rotation took about an hour, after which the Blue group was sent to the 

dumpster/car fire props at approximately 1600 hours. On the way, the trainees walked through the 

apparatus building to get a drink but found the Gatorade® jug empty. They drank as much water as 

possible using the 6-ounce cups provided. Trainees who brought their own bottled water or Gatorade®

refilled their bottles at this point with water. This break lasted approximately 20–25 minutes. 

The Blue group reported to the dumpster/car fire props which provided no shade. The trainees were 

required to wear full bunker gear with SCBA and facepieces. At this point, most trainees were 

reportedly exhausted. Between rotation of the dumpster and car fires, all trainees went to the un-shaded 

rehab where they doffed their turnout gear and drank fluids for about 5 minutes. Then they donned 

their gear and moved to the car fire prop. All those present reported that Trainee A appeared to be 

holding up better than everyone else. Trainee A told an instructor that he “worked outside digging 

ditches all day and this didn’t bother him at all. In fact, he was enjoying it.” 

Upon completion of the car fire prop, the day’s training was completed for the Blue group. They 

removed their PPE and SCBA, took a short break, drank fluids, and reloaded the equipment and hoses 

on the fire engine. Shortly thereafter, Trainee A asked a staff member if he could go to the bathroom 

without his “buddy.” Since the training was completed and only clean-up remained, he was allowed to 

go alone.
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Sometime after Trainee A arrived at the apparatus building, he talked to another trainee for a few 

minutes and they decided to check on another trainee at the burn building. Trainee A and his fellow 

trainee returned to the apparatus building where Trainee A mentioned changing clothes and went into 

the bathroom. 

As the other two groups concluded their burn building exercise, two instructors entered the bathroom 

(about 1810 hours), but neither noted Trainee A in the stall. Three trainees came into the bathroom; 

each trainee reported seeing bunker boots in a normal position under the stall door. They spoke to the 

person in the stall but received no response. Several minutes later, a staff member checked the 

bathroom and noted someone’s boots and legs sticking out of the stall at an unusual angle. The staff 

member opened the stall door and found Trainee A unresponsive in the stall. The staff member yelled, 

“We have a man down in the bathroom” and another staff member called 9-1-1 (about 1815 hours). 

The paramedic and two staff members responded and found Trainee A unconscious, not breathing, and 

without a pulse. They called for the automated external defibrillator (AED) and medical kit and moved 

Trainee A to the floor and checked for a pulse. Finding no pulse, the paramedic began rescue breathing 

with a pocket mask; CPR was initiated by a staff member. The medical kit arrived but did not have 

tubing to provide supplemental oxygen to the pocket mask or bag-valve-mask. The AED arrived 

seconds later and no shock was advised. CPR continued for 9 additional AED assessments, all with no 

shock advised. 

The ambulance arrived at 1824 hours and the paramedics assumed patient care. A cardiac monitor 

revealed asystole. An intravenous (IV) line was placed and Trainee A was intubated. Endotracheal tube 

placement was confirmed by end tidal carbon dioxide testing [AHA 2016]. Cardiac resuscitation 

medications were administered. Trainee A remained in asystole, CPR continued, and Trainee A was 

loaded into the ambulance. The ambulance left the scene at 1839 hours and arrived at the hospital at 

1847 hours. ED staff immediately took over advanced life support treatment from the ambulance crew. 

Resuscitation efforts continued for an additional 24 minutes without success. Trainee A was 

pronounced dead at 1911 hours. 

Medical Findings

The death certificate and autopsy (completed on June 2, 2008 by the State Medical Examiner) listed 

“hyperthermia” as the cause of death, with “hypertensive atherosclerotic cardiovascular disease” and 

“obesity” as other significant medical conditions. Pertinent findings from the autopsy are listed in 

Appendix D. 

Trainee A was 72 inches tall and weighed 268 pounds, giving him a body mass index (BMI) of 

36.3 kilograms per meters squared (kg/m2

) [CDC 2015]. Trainee A had a history of ulcerative colitis 

and obesity. According to his family and crew members, Trainee A had no complaints of chest pains, 

unusual shortness of breath on exertion, or any other heart-related illness. The day before his collapse, 

he worked outdoors at his regular job in Water Department maintenance for a local city. 

Fire Department

At the time of the NIOSH investigation, Trainee A’s volunteer fire department consisted of 10 fulltime uniformed personnel and 10 part-time personnel in training and/or on probation and served a 

population of 800 in a 15-square-mile area. It had 1 fire station. 
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Membership and Training

The fire department requires the following of all fire fighter applicants: be at least 18 years of age, pass 

a fire department vote, and attend meetings and training. 

The successful applicant is placed into a training program and scheduled to attend the 136-hour FFI 

course through State Fire Service Training. Upon completion of this course, the candidate must pass 

the 8-hour live-fire evaluation to achieve the complete FFI certification. Trainee A had just completed 

the FFI certification course, was certified in Hazardous Materials Awareness, and had 8 years of 

firefighting experience.

Medical Evaluations 

Pre-placement and annual medical evaluations, medical clearance for respirator use, and annual SCBA 

fit testing were not required by the fire department. 

If a fire fighter is injured on duty, a return-to-duty medical clearance is required from the fire fighter’s 

primary care provider and given to the Fire Chief, who makes the final determination for return-toduty. 

Wellness/Fitness Programs

The fire department does not have a wellness/fitness program. Strength and aerobic equipment is not 

available at the fire station. An annual physical ability test is not required.

State Fire Service Training Medical Requirement

The State Fire Service Training requires each trainee to identify health problems on their course 

application, and the information is reviewed by the lead instructor. However, no medical 

precertification or evaluation is required. In this case, Trainee A identified “ulcerative colitis” on his 

application. 

Discussion 

Hyperthermia, Heat Stress/Strain, Tolerance, Fluid Balance, Heat Illness, and Heat Stroke

Hyperthermia is characterized by an uncontrolled increase in body temperature that exceeds the body’s 

ability to lose heat [CDC 2006]. Exertional hyperthermia is defined as a core body temperature above 

104°F during activity [Armstrong et al. 2007]. Although, Trainee A’s core body temperature was not 

measured during rehab or in the ED, the death certificate and autopsy completed by the Medical 

Examiner listed “hyperthermia” as the cause of death based on clinical scenario. 

Heat stress/strain. Heat stress refers to the overall heat load on a body from all sources - the 

environment (e.g., air temperature, humidity), physical activity (produces body heat), and protective 

clothing/PPE (traps body heat) [NIOSH 2016]. Above a certain threshold of excess heat storage, the 

body responds with cooling mechanisms to remove the heat and restore balance. The skin is the key 

site of heat transfer. An increase in blood flow moves heat from the warmer core of the body out to the 

skin surface (cutaneous dilation), where the excess heat is expelled to the surrounding environment. 

Greater skin blood flow also facilitates evaporation of sweat from the skin, which is the most effective 

way for the body to eliminate excess heat.
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Heat strain refers to the physiological effects and consequences of heat stress [DOD 2003]. 

Cardiovascular strain occurs when the heart must pump faster to maintain a higher cardiac output to

increase blood flow to the skin. Thermal strain refers to an increase in deep body or “core” temperature 

as a result of stored heat (excess heat). If the body lacked the ability to sweat and increase skin blood 

flow to remove stored heat, core temperature would rise quickly and reach an unsafe level after about 

15 minutes of moderate exercise [Kenney and Johnson 1992]. 

Heat tolerance. The ability to tolerate heat stress is highly individual. About half the variation between 

people is explained by differences in body size and aerobic fitness [Wyndham 1973]. The remainder 

may involve differences in sweat production, circulatory capacity, hormonal effects on fluid and 

electrolyte balance, and other factors that are not well understood. Even in the same person, tolerance 

to the same heat load can vary day to day because of current physiological status, e.g., hydration, 

underlying illness, medications, sleep, or fatigue [DOD 2003; NIOSH 2016]. 

Heat acclimatization is the process of developing improved tolerance to work or exercise in the heat, 

and this develops with repeated episodes of exertion in a hot environment over the course of 

consecutive days to weeks [DOD 2003; NIOSH 2016]. After becoming acclimatized, work output 

increases with reduced physiological strain (lowered heart rate and body temperature), which decreases 

the risk for serious HRI or injury [Casa et al. 2009; DOD 2003; Moseley 1994; NEHC 2007]. A high 

level of aerobic fitness provides partial acclimatization to heat, as the metabolic heat of exercise 

confers physiological benefits that are similar to those from environmental heat [Nunneley and 

Reardon 2002; Tipton et al. 2008]. 

Fluid balance. The sweating rate is influenced by level of physical activity, environmental heat, 

clothing/PPE worn, and whether or not a person is acclimatized [DOD 2003]. Once acclimatized to 

heat, sweating starts earlier and is produced in larger volume. Thus, acclimatization actually increases 

net body water loss; improved electrolyte retention offsets this somewhat by helping maintain plasma 

volume (the fluid portion of whole blood). Around 1 liter/hour of sweat is lost during strenuous heatexertion and around 2 liters/hour if limited permeability PPE is worn, e.g., fire fighters [DOD 2003; 

Eglin et al. 2004]. Being proactive with fluid replacement is key, as onset of thirst does not begin until 

about 1%–2% of body water is lost [Hubbard et al. 1990]. (Given that one pound of body weight 

equates to about 16 ounces of water, sweating in a 200-pound adult which causes 2% weight loss 

[4 pounds] would yield a fluid deficit of approximately 2 quarts [64 ounces].) 

Rehydration is ideally accomplished by drinking small quantities of water at regular, frequent 

intervals, e.g., every 15–20 minutes, instead of drinking a large volume all at once [McArdle et al. 

2010]. The stomach empties at a rate of approximately 1.2 quarts (38 ounces) per hour, which may 

increase with mild exercise but slows down during maximal exercise [Marzio et al. 1991]. Electrolytecarbohydrate sports drinks are recommended if prolonged exertion (e.g., ≥ 1–2 hours) with heavy 

sweating is likely, in order to replace electrolytes lost in sweat and prevent dilutional hyponatremia 

[Montain and Cheuvront 2008; NFPA 2015a]. 

Dehydration (reduced total body water) negates the physiological advantages of acclimatization, 

particularly when fluid losses exceed 2% of body weight [DOD 2003; Greenleaf and Harrison 1986; 

Taylor et al. 2008]. Progressive dehydration increases physiological strain and impairs the body’s 

ability to cool itself. The production of sweat declines, the contracted blood volume strains the heart to 

pump faster, and core temperature rises by approximately 0.12°F–0.15°F (~0.2°C–0.3°C) for each 1% 
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of weight loss [González-Alonso et al. 2008; Grucza et al. 1987; Sawka et al. 1985]. Work/exercise 

endurance decreases, and fatigue occurs earlier [Buskirk et al. 2000; Cheuvront et al. 2010; DOD 

2003; NIOSH 2016]. Thus, dehydration compounds the effects of hyperthermia and the risk of HRI, 

including heat stroke, increases. 

Heat-related illness. Core temperature may become elevated (hyperthermia) but remain steady during 

strenuous activity, with heat gains balanced by heat losses. Being adequately hydrated, acclimatized, 

and aerobically fit helps prevent the likelihood of hyperthermia and serious HRI; however, these 

protective factors do not eliminate the risk [Armstrong et al. 2007; Binkley et al. 2002; DOD 2003; 

NIOSH 2016]. Core temperature can leave its steady state if the body’s ability to compensate for heat 

gains becomes overwhelmed. For example, if evaporative cooling ability is inhibited by PPE and/or 

high humidity conditions, core temperature can escalate and HRI becomes more likely [DOD 2003]. 

Exertional heat exhaustion. Exertional heat exhaustion is the most common HRI among active people. 

It is characterized by physical exhaustion and the inability to continue work or exercise due to 

insufficient cardiac output. Heart rate, which largely drives cardiac output, may reach its physiological 

upper limit while trying to meet the combined demands of increased blood flow to the skin, exercising 

muscle, and vital organs such as the heart and brain [Armstrong et al. 1997; DOD 2003]. Other 

signs/symptoms of exertional heat exhaustion may include profuse sweating, headache, irritability, 

weakness, nausea, feeling dizzy or light headed, tachycardia, etc. If present, hyperthermia with heat 

exhaustion may be mild to moderate (100.4°F–102.2°F / 38°C–39°C), which some individuals cannot 

tolerate; others, such as marathon runners or elite soldiers, may perform well at even higher 

temperatures [Armstrong et al. 2007; Joy and Goldman 1968]. Once core temperature reaches 102.6°F 

(39.2°C), risk of heat exhaustion collapse is around 25%; as it approaches 104°F (40°C), the majority 

of people will experience an HRI [NIOSH 2016]. 

Exertional rhabdomyolysis. Exertional rhabdomyolysis (breakdown of skeletal muscle) can develop 

during strenuous exertion in the heat as a complication of heat stroke or as a separate injury [DOD 

2003; NIOSH 2015]. When muscles die or are injured, their contents can enter the bloodstream and 

cause damage. Potassium can cause irregular heat rhythyms and seisures while myoglobin, the protein 

that carries oxgygen inside muscle cells, may cause kidney damange clogging the kidney’s filtration 

systemIn about 25% of cases,myoglobin induced kidney damage is severe enough to cause acute renal

failure [NEHC 2007]. Classic symptoms of exertional rhabdomyolysis include localized muscle pain 

worse than expected for the exetion, swelling of the affected muscle, and new inability to complete 

previously routine physical tasks; urine may appear very dark or “tea” colored from myoglobinuria 

[Brown 2004; Sawka et al. 2007]. Hospitalization to receive intravenous fluids to flush out the 

potassium and restore fluid balance, temporarly dialysis if/until kidney function recovers, and cardiac

monitoring may be necessary to ensure recovery from severe cases of rhabdomyolysis. 

Heat Stroke. Heat stroke is a life-threatening emergency of failed thermoregulation with severe 

hyperthermia (> 104.9°F / 40.5°C) and central nervous system (brain) dysfunction, often with loss of 

consciousness [Armstrong et al. 2007]. The brain is particularly sensitive to hyperthermia and thus 

shows dysfunction early on; heat stroke may be further complicated by a cascade of damage to other 

organ systems that resembles the sepsis syndrome [Bouchama et al. 2005; Walter and Carraretto 2016]. 

Exertional heat stroke primarily strikes young, active people who are usually still sweating at the time 

of collapse [NIOSH 2016]. This differs from nonexertional or “classic” heat stroke which affects the 

elderly and chronically ill during heat waves, and in whom sweating has often ceased. Exertional heat 
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stroke is a particular threat to fire fighters, the military, athletes, and others whose work or training 

involves intense physical effort in the heat while wearing limited permeability PPE or gear that traps 

body heat [Goforth and Kazman 2015]. 

Because internally generated heat is its root cause, exertional heat stroke can develop even during cool 

conditions that may be mistakenly considered “safe” [Armstrong et al. 2007; Giercksky et al. 1999; 

Stacey et al. 2015]. The time to reach severe hyperthermia can be short, ranging from approximately

30 minutes to several hours [Rav-Acha et al. 2004]. Many cases go unrecognized until collapse. 

Possible earlier signs or symptoms include headache, nausea, confusion (e.g., failure to follow 

commands), irrational or out of character behavior, slurred speech, clumsiness, staggering, etc. [DOD 

2003; Epstein et al. 1999]. Exertional heat stroke mortality in epidemiological studies (analyses of 

groups or populations) ranges from about 4% to 22% [Carter et al. 2005; Rav-Acha et al. 2004; 

Shibolet et al. 1976; Zeller et al. 2011]. Duration of hyperthermia before cooling affects prognosis 

more so than the peak core temperature reached [Shapiro et al. 1973]. Prompt immersion in ice water 

has been endorsed by national sports medicine and athletic training associations as the best method to 

rapidly lower core temperature and improve outcomes [Armstrong et al. 2007; Casa et al. 2015; Leon 

and Bouchama 2015; McDermott et al. 2009; Smith et al. 2005]. As this case suggests, heatstroke can 

be the presenting illness. Trainee A probably had heatstroke and ice water immersion was not available 

at the PSC.

Trainee A’s presentation and clinical course, which followed training in hot environmental conditions, 

was typical of exertional heatstroke. As noted above, Trainees B and C reported symptoms consistent 

with mild to moderate HRI during this live-fire training. Trainee C required medical evaluation onscene, while Trainee B required medical evaluation and treatment at the local ED. 

Risk Factors for Heat-Related Illness/Exertional Heat Stroke

Predisposing factors for HRI/exertional heat stroke have been identified, including metabolic heat 

generation, external factors and internal (personal) factors [Abriat et al. 2014; Armstrong et al. 1990; 

NEHC 2007; Rav-Acha et al. 2004; USAPHC 2016]. These factors are discussed below as they relate 

to this incident.

Metabolic Heat Generated During PSC Live-Fire Training

For those engaged in moderate to heavy physical work, metabolic heat is the primary driver of heat 

stress. Using the descriptions of the training tasks as written in the PSC procedures manual and during 

NIOSH interviews, the metabolic heat generated could be estimated by task analysis for each training 

evolution (Example calculations are provided in Appendices E-I). These energy expenditures ranged 

from light (most exterior fire evolutions) to moderate (hidden wall evolution) to heavy (interior 

evolution). These estimates are modestly lower than exertion/work estimates obtained during actual 

and simulated fire suppression in SCBA and turnout gear [Bugajska et al. 2007; Lemon and Hermiston 

1977; O’Connell et al. 1986]. However, when the weight adjustment factor for Trainee A is taken into 

account (see Appendix E-I), his evolution work estimates were in the moderate to heavy exertion 

ranges.
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External Risk Factors

Environment. Environmental heat is determined by four factors: air temperature, humidity, air 

movement, and radiant heat. The commonly used “heat index” reported by the U.S. National Weather 

Service accounts for air temperature and humidity, whereas the WBGT index also accounts for radiant 

heat and wind [NIOSH 2016; Parsons 2006]. Thus, measuring or estimating the WBGT is important 

for two reasons. First, it is a more accurate index of environmental heat load. Second, it is used in HRI 

prevention guidelines [ACGIH 2017; Armstrong et al. 2007; NIOSH 2016; Parsons 2006]. 

In this incident, neither the training facility nor the course instructors had equipment to measure the 

WBGT. Formulas, however, have been developed that estimate WBGT using routinely collected 

meteorological data [ABM 2010; Lemke and Kjellstrom 2012; Liljegren et al. 2008]. At 1330 hours, 

the dry bulb temperature was 89°F, the wet bulb temperature was 78°F, the humidity was 59%, and the 

wind was 11 Miles per hour (mph) with scattered cloud cover. Under these conditions, the Australian 

Bureau of Meteorology method would estimate the WBGT to be 90°F (32°C) (Appendix J), although 

the validity of the Australian Bureau of Meteorology method has been questioned [Lemke and 

Kjellstrom 2012].

Clothing Adjustment Factor, Fire Fighter Turnout Gear, and PPE. Heat is removed from the body 

primarily by evaporation of sweat from the skin. Clothing alters the amount and rate of heat exchange 

between the skin and the ambient air by convection, radiation, and evaporation [NIOSH 2016]. In 

general, the thicker the garment and the greater the air and vapor impermeability of the clothing, the 

more it interferes with the body’s cooling process. In evaluating heat stress, a “clothing adjustment 

factor” must be applied to the WBGT [ACGIH 2017; NIOSH 2016]. The turnout gear worn by fire 

fighters is a multilayer garment (three layers of outer shell, moisture barrier, and thermal liner) with 

partial air/vapor impermeability [Duffy et al. 2008]. A clothing adjustment factor of 10°F to 20°F 

(6°C to 11°C) for fire fighter turnout gear has been suggested [Bernard 1999; Duffy et al. 2008; 

Pennington et al. 1980]. Thus, the effective WBGT in this incident would have been 100°F to 110°F 

(38°C to 43°C). 

On the day of the incident, Trainee A wore the full PPE required for live-fire training for over 3 hours. 

He collapsed at the end of the 10-hour training. 

Exertion. Any protective clothing/equipment will limit heat tolerance to a certain extent by adding 

weight and altering heat transfer [NIOSH 2016; White and Hodous 1987]. The physiological burden of 

protective clothing can increase core temperature, cardiovascular strain, and physical fatigue, and 

lessen the time to reach exhaustion [Armstrong et al. 2010; Barr et al. 2010; NIOSH 2016; Petruzzello 

et al. 2009]. The features of fire fighter PPE that protect against the hazards of fire fighting are also the 

characteristics that increase the risk of HRI. The insulating layer of the turnout coat traps body heat 

and the semi-permeable moisture barrier impedes sweat evaporation [Eglin 2007]. The SCBA 

increases the work of breathing (metabolic heat) [Jones 1991]. In addition, metabolic workload and 

thus body heat are increased by the substantial weight of PPE and SCBA (the weight of structural fire 

fighter protective clothing plus SCBA and tank is approximately 40–50 pounds [Haddam Volunteer 

Fire Company 2013]). PPE and SCBA contributed to the heat stress experienced by Trainee A. 

Based on descriptions of the live-fire prop, the exterior hidden wall fire prop, the exterior fire 

extinguisher prop, the pallet/dumpster fire prop, and the car fire prop, protective clothing 

ensemble/SCBA considerations, and workload estimates [NFPA 2015a; NIOSH 2015], the metabolic 
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workload for the live-fire training was estimated to be in the range of 350–740 kilocalories per hour 

(kcal/hour) (moderate to heavy workload). Since the live-fire training was required for FFI

certification, this could have led to its intensity. Prior to Trainee A’s collapse, instructors had already 

treated 2 trainees for heat exhaustion and transported one of them to the hospital for treatment. The 

exertion and intensity of the live-fire training contributed to the heat stress experienced by Trainee A.

Personal Risk Factors

The literature describes personal risk factors for exertional heatstroke, some of which include increased 

age, obesity, poor physical fitness, a previous history of exertional heatstroke, and various medical 

conditions such as heart disease. Some medications and other ingested substances (e.g., alcohol, 

dietary supplements) can impact the body’s ability to regulate heat [Armstrong et al. 2007]. 

Trainee A was obese and had ulcerative colitis, an inflammatory disorder of the large intestines that 

can cause diarrhea. Trainee A suffered “flare-ups” of this condition on the morning before, and the 

morning of, the live-fire training. This may have exacerbated Trainee A’s dehydration found at 

autopsy, but it is unclear what role, if any, it played in Trainee A’s sudden death. During the safety 

briefing and throughout the day, hydration was emphasized. To prevent dehydration, the PSC 

coordinator reminded the trainees to drink the water and Gatorade® provided at 3 locations: (1) a 10-

gallon jug in the rehab pavilion near the burn building, (2) a 5-gallon jug near the car/dumpster fire 

prop, and (3) two 5-gallon jugs in the apparatus bay near the classroom. Several water jugs and one jug 

of Gatorade® were reportedly empty throughout the day. Access to drinking water could have been a 

problem. Trainee A reportedly drank Gatorade® during the training. 

Prior to the training, Trainee A was not known to have heart disease. The autopsy, however, revealed 

moderate coronary artery disease (CAD), left ventricular hypertrophy (LVH), and cardiomegaly. These 

conditions increase the risk of sudden cardiac death [Levy et al. 1990]. While it is unlikely Trainee A

died due to a cardiac event, this cannot be ruled out. 

Lack of heat acclimatization is another heatstroke risk factor. With heat acclimatization, physiological 

changes such as sweating at a lower temperature, more sweating, and less electrolyte loss make the 

body more efficient in dealing with heat stress. Any exercise program that builds and maintains a high 

level of aerobic fitness partially adapts the body to heat stress [Nunneley and Reardon 2009]. To fully 

acclimatize, however, the body needs to experience the actual work conditions in consecutively 

increasing 11⁄2- to 2-hour increments. Adaptive physiological changes occur within 4 days, but 

complete acclimatization can take up to 3 weeks [Voltaire et al. 2002]. Once heat stress exposure 

stops, the body’s adaptive mechanisms regress; clinically significant reductions are seen within 4 days 

[ACGIH 2017]. 

Exertional heat stroke has been called the “illness of the over-motivated” [Epstein et al. 1999]. High 

motivation or “overzealousness” has been identified as a risk for heat stroke among military members 

and athletes [Abriat et al. 2014; DOD 2003; Rav-Acha et al. 2004; USAPHC 2016]. A strong desire to 

meet or exceed standards to complete a mission causes some soldiers to continue pushing themselves 

despite early signs or symptoms of exertional heat stroke. Athletes, especially during competition, may 

ignore early warning signs or symptoms that would normally be protective [Cleary 2007; Lopez et al. 

2011]. In other words, in the setting of heat strain, judgment may be impaired among those who are 

highly motivated to perform well. 
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Summary of Predisposing Risk Factors. Trainee A had a “flare up” of his ulcerative colitis which 

can cause diarrhea which can lead to dehydration. Once the training began, Trainee A was exposed to 

multiple sources of heat stress – environmental heat, physical exertion, heat-trapping protective 

clothing, SCBA, the overall weight of PPE/SCBA, and high motivation. The autopsy showed he was 

dehydrated. 

Guidelines for Workers/Athletes at Risk for Heat-related Illness and Exertional 

Heatstroke 

Several organizations have developed guidelines for stopping or restricting physical activities on the 

basis of WBGT, metabolic work requirements, clothing adjustment factors, and acclimatization. For 

heavy (415 kcal/hour) work among acclimatized individuals, the U.S. Army and Air Force cancel all 

scheduled physical training in acclimatized individuals when WBGT is above 32.0°C (89.6°F) 

[Nunneley and Reardon 2009; Pennington et al. 1980]. The American College of Sports Medicine 

recommends cancelling all scheduled events when WBGT is above 32.3°C (90.14°F) [Armstrong et al. 

2007]. NIOSH recommends discontinuing heat exposure (work) for acclimatized workers on 

moderately physically demanding jobs (300 kcal/hour) when the WBGT is above 32°C (89.6°F) 

[NIOSH 2016]. The American Conference of Governmental Industrial Hygienists (ACGIH) 

recommends discontinuing heat exposure (work) for acclimatized workers doing moderately physically 

demanding work when the WBGT rises above 31.5°C (88.7°F) [ACGIH 2017]. 

It should be noted that the NIOSH and ACGIH guidelines are based on an 8-hour workday and a 

40-hour workweek. The PSC live-fire training lasted 10 hours, however less than half of the time was 

actually spent doing fire suppression. However, many trainees reported not having enough time 

between props to doff their turnout gear or were told not to doff their turnout gear due to the safety 

concerns in the immediate vicinity of the props. In addition, the 10-minute rest periods between props 

was probably not long enough to effectively lower the fire fighter’s core temperature [McLellan and 

Selkirk 2006]. 

The National Fire Protection Association (NFPA) also provides guidelines [NFPA 2015a]. In the 

Annex of NFPA 1584, the organization lists both a “Heat Stress Index” and the HUMIDEX both 

derived from air temperature and humidity. A footnote under the Heat Stress Index suggests adding 

10.0°F when wearing protective clothing and 10.0°F when working in direct sunlight, but a similar 

correction factor is not included in the HUMIDEX Chart. Using the temperature and humidity 

measurement at 1330 hours, the HUMIDEX index was 43 which translates to an Alert Level 2 = 

Extreme Caution. At this level, NFPA recommends the following:

(1) Postpone optional activities or reschedule them to cooler times of the day when possible. 

(2) Introduce additional rest breaks for workers performing moderate work. 

(3) Further reduce heavy work. 

(4) Consider cessation of nonessential operations involving heavy physical activity.

(5) Minimize using bunker suits whenever possible. 

NFPA 1584 goes on to recommend postponing all training activities except recruit training. When 

conducting recruit training within the HUMIDIX 40–45 range, the following is recommended: 

(6) Limit recruit live-fire burns to occur between 0700–1200 hours only. 

(7) Provide increased rest break for all work loads. 
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(8) Limit heavy work to less than 15 minutes per hour. 

(9) Initiate rehabilitation at the beginning of the incident.

(10) Use active cooling where possible (forearm immersion, misting fan, and/or air conditioning). 

Given that two trainees suffered heat exhaustion in the morning, and the estimated WBGT was 90°F 

(32°C), strong consideration should have been given to cancelling the afternoon training session. In 

addition, trainees and instructors were not allowed to remove any bunker gear while in the immediate 

vicinity of the props due to safety concerns. This increased the duration of heat exposure. When the 

clothing adjustment factor is taken into account [WBGT estimated to be between 100°F–110°F 

(38°C–43°C)], the training session should have been cancelled according to the U.S. Army, U.S. Air 

Force, American College of Sports Medicine, NIOSH, and ACGIH. Since the decision was made to 

continue the training, at least the NFPA recommendations 6–8, and 10 should have been followed (#9 

was already in place).

Treatment. Rapid core body temperature reduction is the most important treatment for exertional 

heatstroke. Its use has resulted in lower exertional heatstroke mortality rates [Bouchama et al. 2007; 

Costrini 1990; McDermott et al. 2009]. Cold/ice water immersion is the best method and is endorsed 

by the ACSM and the National Athletic Trainers’ Association [Armstrong et al. 2007; Binkley et al. 

2002]. Cold/ice water immersion was not available on site.

Rehab Standards for Structural Fire Fighters. NFPA 1584, Standard on the Rehabilitation Process for 

Members During Emergency Operations and Training Exercises, establishes the minimum criteria for 

developing and implementing a rehab process for fire department members at incident scene 

operations and training operations [NFPA 2015a]. Components of the rehab should include (1) rest and 

relief from climate conditions, (2) medical evaluation and treatment, and (3) fluid and food 

replenishment. 

1. Rest and Relief. Rehab was provided, however during rehab, some trainees were required to prepare 

excelsior fuel for the burn props while wearing bunker pants, boots, gloves, and helmet. In addition, in 

some situations a group could move from one prop to the next (e.g., Blue group) without an 

opportunity to cool down in Rehab. 

NFPA 1584 also recommends that an adequate area and/or shelter be available during operations and 

training. For hot environments, this includes shade and/or air conditioning and a place to sit [NFPA 

2015a]. One rehab area at the Skills Center did not have shade and the only air-conditioned area at the 

Skills Center was the classroom.

Members entering rehab for the first time should rest for a minimum of 10 minutes or longer if 

practical [NFPA 2015a]. Following the use of a second 30-minute SCBA cylinder, a single 45-minute 

or 60-minute SCBA cylinder, or 40 minutes of intense work without SCBA, a minimum of 20 minutes 

rest is required [NFPA 2015a]. In this training session, a few of the rehab visits lasted only 5 minutes. 

A member must not return to operations if he/she does not feel adequately rested; if emergency 

medical or supervisory staff see evidence of medical, psychological, or emotional distress; or if the 

member appears otherwise unable to safely perform his or her duties [NFPA 2015a]. In this case, a 

culture existed in which instructors believed trainees would come forward when they needed a break; 

and, conversely, in which trainees believed they were inadequate if they came forward to express this 

need. This culture included trainee knowledge that if they sought medical attention and/or were 
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transported to the hospital, they would not be allowed to continue the testing process. The SOG stated 

that if a trainee was transported to the hospital, the trainee could not complete FFI training with his/her 

class. They would have to return to the Skills Center at a later date to repeat the entire testing process.

2. Medical. NFPA recommends a written standard operating guideline (SOG) [NFPA 2015a]. This 

guideline should include a medical component. In this training, a lesson plan was written, but it did not 

include a medical component, and the course application form did not mention rehab, hydration, or 

medical requirements. Although trainees were observed by instructors, vital signs were not taken as a 

baseline prior to training, upon entering rehab, or upon leaving rehab. 

3. Fluids. The training center emphasized adequate hydration at numerous times prior to, and during 

training. For scheduled events, pre-hydration should include an additional 16 ounces of fluids within 

2 hours prior to the event. Throughout the training exercises fluids (water and Gatorade®) were 

available, although the jugs were occasionally found to be empty by trainees. These jugs were 

subsequently refilled.

Live-fire Training Standards for Structural Fire Fighters. NFPA 1403, Standard on Live-fire 

Training Evolutions, contains the minimum requirements for training fire suppression personnel under 

live-fire conditions [NFPA 2007, 2012]. (The 2007 edition was current when this incident occurred). 

As required by NFPA 1403 a pre-burn briefing and a walk-through of the burn building prior to 

conducting live-fire training were performed [NFPA 2007]. However, in 2005, the State Fire Service 

Training made some changes. For safety reasons simulated and/or practice burns to the burn building 

and the car fire/dumpster fire props were added. These changes resulted in a longer training day, which 

lead to increased heat exposure and physical exertion. Our record review indicated that since 2005, an 

average of 1 trainee per 3.6 live-burn classes have been transported to the hospital for HRIs. 

Additionally, the large class size (25 trainees) resulted in a longer training day. 

There must be an awareness of weather conditions including the amount of sunshine and wind speed. 

The training should be modified, postponed, or canceled, as necessary for extreme weather conditions 

[NFPA 2015a]. The instructors were aware of the weather, including temperature and humidity, but 

there was no written guideline for shortening or modifying the training in a hot environment, nor were 

there another correction factors for sunshine or wearing turnout gear. 

All State Fire Service Training instructors that participate in live-burn training were trained to comply 

with NFPA 1403. An NFPA 1403 checklist was completed prior to the training, and the local fire 

department was notified. However, an ambulance was not available at the PSC.

The lesson plan for conducting live-fire training evolutions included the following: check in and 

welcome, facilities information, safety briefing, NFPA 1403 compliance plans, walkthrough 

demonstrations, and exam information. However, there was no guidance requiring medical 

information. 

Emergency medical services (EMS) personnel are required to be available on-site at training activities 

to handle injuries [NFPA 2007, 2012]. However, the State Fire Service Training did not have an 

ambulance, and the closest emergency medical transport unit and advanced life support unit were over 

9 minutes away. Furthermore, the State Fire Service Training did not operate under the supervision of 

a Medical Director or have medical protocols other than the State First Responder Protocol. Therefore, 

a paramedic may be on-site, but can only provide care at the first responder level (check vital signs, 
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administer oxygen through a non-rebreather mask, provide CPR with a pocket mask, and utilize an 

AED). The lead instructor at the training session was a paramedic, but available emergency medical 

equipment was only basic life support. 

The instructor-in-charge (lead instructor/paramedic in this case) is responsible for coordinating overall 

live-fire training area fireground activities to ensure proper levels of safety [NFPA 2007, 2012]. While 

there were an adequate number of instructors to teach and perform other functions, the lead instructor 

had many responsibilities, including oversight of the entire training session, participating as an 

instructor, primary emergency medical person on-scene, and completion of all required paperwork. 

Recommendations 

Recommendation #1: Conduct live-fire training exercises consistent with NFPA 1403, Standard on 

Live-fire Training Evolutions.

Discussion: Dedicated emergency medical personnel, with a minimum of basic life support capabilities

(BLS), must be standing by at all live-fire exercises.

The lead instructor should be free to oversee the live-fire training without the added responsibilities of 

instruction and medical treatment. While the lead instructor is performing one task, other areas of 

training, including rehab, may not receive adequate oversight.

Consider revising the live-fire training standard to give credit for completed blocks of training. Due to 

trainee/instructor relations and perceptions, trainees may be intimidated by instructors. Trainees may 

continue intense physically-exerting training in order to complete a course or block of training, even 

though they are at increased risk of a serious/life-threatening health event. If the training standard 

allowed for credit to be given for completed blocks of training, trainees would only have to complete 

the portions they missed. Since the live-fire training had several portions, each portion could count as a 

separate block.

Another option to consider is to lengthen the live-fire exercises to a two- or three-day event with 

adequate down time during periods of elevated environmental conditions. 

A third option to consider is to conduct the live-fire classes in the spring or fall.

Recommendation #2: Formulate and institute a heat stress prevention program. Minimize 

disincentives to reporting of symptoms. For example, reconsider policy of not allowing trainees to 

return to their training course once medically cleared if they left training to seek care for possible 

HRI and/or rhabodmyolysis. Such a policy creates a disincentive for seeking prompt medical care 

which may place trainees at an increased risk. 

Discussion: A number of guides recommend measures and standards for protection from heat stress 

injuries. A list can be found in the NIOSH Criteria for a recommended standard, Occupational 

Exposure to Hot Environments [NIOSH 2016]. This criteria document contains standards and 

recommendations from ACGIH, Occupational Safety and Health Administration (OSHA), American 

Industrial Hygiene Association, the Armed Forces, American College of Sports Medicine, and the 

International Organization for Standardization. Although there are occupation/industry-specific 

components found in each group’s documents, the State Fire Service Training should examine all the 

guides in their updated form to identify policies that fit their unique situation. A program should 

include heat casualty risk management (identify and assess hazards; develop and implement controls; 
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and supervise and evaluate the program) [Department of the Army Training and Doctrine Command 

2005], education, a surveillance system for early detection, and compliance monitoring. 

When to restrict/cancel live-fire training should be determined based on the heat stress index. When 

protective clothing is worn, 10°F is added to the index. When in direct sunlight, 10°F is added to the 

index. Based on available information, training should be monitored carefully when apparent 

temperature exceeds 90°F; modified or suspended when apparent temperature exceeds 105°F. At 1540 

hours on the date of this incident, the basic heat index was 98°F. However, since Trainee A was 

wearing full bunker gear, the heat stress index was 108°F (the danger zone). Heat cramps or exhaustion 

is likely, and heat stroke is possible, if exposure is prolonged and there is physical activity. According 

to the Canadian index, the Humidex, the heat index (including the gear) was 115°F during this 

incident (danger zone) [NFPA 2015a]. Therefore, in high-heat environments, it is recommended to: 

(1) significantly reduce both heavy and moderate work, (2) minimize using bunker suits whenever 

possible, (3) consider cessation of non-essential operations involving moderate physical activity, and 

(4) cease all non-essential operations involving heavy physical activity [NFPA 2015a]. 

Consider the following program elements taking place before, during, and after all training courses: 

BEFORE TRAINING

• Ensure onsite EMS personnel assess trainee risk for heat illness prior to participation in 

strenuous training (to include any training in full turnout gear); consider use of a checklist or 

other screening tool for this purpose. 

DURING TRAINING

• Ensure onsite EMS personnel regularly monitor trainees for early signs and symptoms of HRI

(e.g., overall appearance, mental status, pulse, temperature) at a frequency based on training 

duration, intensity, and other factors relevant to heat stress. Ensure instructors brief trainees on 

the process for promptly reporting suspected HRI in themselves or fellow trainees.

• Ensure trainees are hydrated at all phases of physically demanding tasks.

AFTER TRAINING

• Ensure trainees rehydrate during rehab to fully replace fluid losses from sweating. For multiday training exercises, encourage trainees to increase fluid intake during time away from 

training (off-duty hours, rest days) to reduce the risk of dehydration on subsequent training 

days [NIOSH 2015]. 

• Seek input from trainees and instructors about removing barriers, real and perceived, to 

reporting or seeking medical attention for signs/symptoms of possible HRI. 

Recommendation #3: Institute a rehabilitation (rehab) program consistent with NFPA 1584, 

Standard on the Rehabilitation Process for Members During Emergency Operations and Training 

Exercises.

Discussion: SOGs should be written that include such rehab components as the following: 

• relief from climatic conditions

• rest and recovery 

• active and/or passive cooling or warming as needed for incident type and climate conditions 
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• rehydration (fluid replacement) 

• calorie and electrolyte replacement

• medical monitoring 

• EMS treatment in accordance with local protocol

• member accountability

• release

SOGs should be distributed to each instructor prior to commencement of live-fire exercises.

Adequate food and fluid replacement should be available. When hydration is taken with a meal, water 

is appropriate. However, although water can quench thirst, it does not provide needed carbohydrates 

and electrolytes. Sports drinks should be considered for rehydration and calorie and electrolyte 

replacement when scheduled activities are of moderate to high intensity and last 1 hour or longer. 

Drinks with caffeine and alcohol are discouraged, as these interfere with hydration by increasing urine 

production [USFA 2008]. 

Expected trainees should be provided with written information on pre-hydration and appropriate

clothing requirements at least 2 days prior to live-fire training. By receiving timely, adequate 

information, prospective trainees could properly prepare for strenuous training in a warmer 

environment. Maintaining adequate hydration at least 2 days prior to training allows the trainee to be 

better physiologically prepared for the physically demanding training. Documentation should include 

information on monitoring urine output, avoiding excessive caffeine and alcohol intake, and drinking 

adequate fluids. A minimum of 6–8 ounces of fluids every 6 hours is recommended. 

The PSC should provide shade in all rehab areas and medical monitoring of all trainees. At the start of 

training, take vital signs of each trainee and document pertinent medical information such as history, 

complaints, or symptoms. Predetermined vital sign criteria should be established for admittance to 

training, assignment to rehab, discharge from rehab, and transport to the hospital. Emergency medical 

personnel should evaluate trainees arriving at rehab and prior to release for symptoms of a health 

and/or safety concern. The evaluation should include a set of vital signs. Symptomatic members or 

members with abnormal findings should receive additional monitoring. Members suffering from heat 

stress should be removed from active duties. If medical care is given, a medical report should be 

completed and maintained [NFPA 2015a].

Rehab time should be dedicated, uninterrupted time. In this case, trainees were required to break apart, 

fluff, and place excelsior in preparation for the live-burns while wearing bunker pants, boots, gloves, 

and helmets. Rehab time should last at least 10–20 minutes after each hour in full bunker gear. If 

adequate rehab time causes the training time to be longer, perhaps the training could be extended over 

2–3 days. Trainees must be directed by instructors and EMS personnel to completely remove all 

bunker clothing, including helmets, gloves, and bunker pants prior to entering the rehab area. 

Instructors must also comply with rehab protocols. Active cooling methods must be provided (i.e., cold 

and wet towels, forearm immersion, misting, etc.).

Recommendation #4: Ensure that all fire fighters receive an annual medical evaluation consistent 

with NFPA 1582, Standard on Comprehensive Occupational Medical Program for Fire 

Departments. 

Discussion: Guidance regarding the content and frequency of these medical evaluations can be found 
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in NFPA 1582 [NFPA 2013a]. These evaluations are performed to determine a fire fighter’s medical

ability to perform duties without presenting a significant risk to the safety and health of themselves or 

others. This medical evaluation should be consistent with the requirements of NFPA 1582. 

Recommendation #5: Ensure fire fighters are cleared for duty by a physician knowledgeable 

about the physical demands of fire fighting, the personal protective equipment used by fire 

fighters, and the various components of NFPA 1582. 

Discussion: According to NFPA 1582, the FD should require that physicians are familiar with the 

physical demands of fire fighting and the risks that fire fighters encounter and should guide, direct, and 

advise members with regard to their health, fitness, and suitability for duty [NFPA 2013a]. The 

physician should review job descriptions and essential job tasks required for all FD positions to 

understand the physiological and psychological demands of fire fighting and the environmental 

conditions under which fire fighters perform, as well as the personal protective equipment they must 

wear during various types of emergency operations. 

Recommendation #6: Phase in a mandatory comprehensive wellness and fitness program for fire 

fighters. 

Discussion: Guidance for fire department wellness/fitness programs to reduce risk factors for 

cardiovascular disease and improve cardiovascular capacity is found in NFPA 1583, Standard on 

Health-Related Fitness Programs for Fire Fighters, the IAFF/IAFC Fire Service Joint Labor 

Management Wellness/Fitness Initiative, the U.S. Fire Administration Health and Wellness Guide for 

the Volunteer Fire and Emergency Services, and in Firefighter Fitness: A Health and Wellness Guide 

[IAFF, IAFC 2008; NFPA 2015; Schneider 2010; USFA 2004]. Worksite health promotion programs 

have been shown to be cost effective by increasing productivity, reducing absenteeism, and reducing 

the number of work-related injuries and lost work days [Aldana 2001; Stein et al. 2000]. Health 

promotion programs for fire fighters have been shown to reduce coronary heart disease risk factors and 

improve fitness levels, with mandatory programs showing the most benefit [Blevins et al. 2006; 

Dempsey et al. 2002; Womack et al. 2005]. 

The FD has does not have exercise equipment available to members and does not have a 

wellness/fitness program. Given the FD’s structure and budget limitations, helpful resources for 

starting a program may include the Heart-Healthy Firefighter Program developed by the National 

Volunteer Fire Council [NVFC, no date] and the Health and Wellness Guide for the Volunteer Fire and 

Emergency Services [USFA 2004]. 

Recommendation #7: Perform an annual physical performance (physical ability) evaluation. 

Discussion: NFPA 1500 recommends fire department members who engage in emergency operations 

be annually evaluated and certified by the FD as having met the physical performance requirements 

identified in paragraph 10.2.3 of the standard [NFPA 2013b]. This is recommended to ensure fire 

fighters are physically capable of performing the essential job tasks of structural fire fighting. The 

physical ability test could be incorporated into the FD’s training program. 

Recommendation #8: Ensure treatment guidelines are followed for a heat-related illness.

Discussion: First aid measures are summarized on the NIOSH “Heat Stress” website 

https://www.cdc.gov/niosh/topics/heatstress/default.html and in many other resources. Transfer to 
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acute medical care should be accomplished as the clinical condition warrants [Danzl 2015; Kraska 

2018]. 

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Investigator Information

This incident was investigated by the NIOSH Fire Fighter Fatality Investigation and Prevention 

Program, Cardiac and Medical Line of Duty Deaths (LODD) Investigations Team in Cincinnati, Ohio, 

Mr. Tommy Baldwin (MS) led the investigation and co-authored the report. Mr. Baldwin is a Safety 

and Occupational Health Specialist, a National Association of Fire Investigators (NAFI) Certified Fire

and Explosion Investigator, an International Fire Service Accreditation Congress (IFSAC) Certified 

Fire Officer I, and a former Fire Chief and Emergency Medical Technician. Drs. Judith Eisenberg and 

Wendi Dick, current and former Team Leads for Cardiac and Medical LODD Investigations 

respectively, provided medical consultation and contributed to the report. The team’s current 

investigator, Robert Saunders, a current fire chief and EMT, also contributed to this report. 

Additional Information 

A number of fire departments across the country have SCBA training props and maze facilities. 

Physiological strain from exertion or heat stress has been involved in medically-related line-of-duty 

deaths that have occurred in SCBA maze trailers. Below are links to other NIOSH fire fighter fatality 

investigation reports involving SCBA maze training. 

Fire Fighter Trainee Suffers Sudden Cardiac Death During Maze Training – Virginia (2008), 

https://www.cdc.gov/niosh/fire/pdfs/face200902.pdf

Captain Dies from Hyperthermia and Exertional Heat Stroke While Performing Advanced Survival 

Training – Texas (2012), https://www.cdc.gov/niosh/fire/pdfs/face201227.pdf 

Disclaimer 

Mention of any company or product does not constitute endorsement by the National Institute for 

Occupational Safety and Health (NIOSH). In addition, citations to websites external to NIOSH do not 

constitute NIOSH endorsement of the sponsoring organizations or their programs or products. 

Furthermore, NIOSH is not responsible for the content of these websites. All web addresses referenced 

in this document were accessible as of the publication date. 
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Photo 1. Burn building. PSC photo. 
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Photo 2. Hidden wall fire prop. PSC photo. 
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Photo 3. Fire extinguisher prop. PSC photo. 
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Photo 4. Pallet/dumpster fire and car fire props. PSC photo. 
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Photo 5. Rehab pavilion. PSC photo. 
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Table 1

Dry and Wet Bulb Temperature, Relative Humidity, and Heat Indices

Nearby Local Airport*

May 31, 2008 

Hour Dry Bulb 

Temperature

Wet Bulb 

Temperature

Relative

Humidity

Wind

(mph)^

Cloud

Cover 

Heat 

Index** 

Estimated 

WGBT*** 

0800 76°F 69°F 69% 8 Partly 77°F 79°F

1100 82°F 74°F 67% 8 Scattered 85°F 84°F

1330 89°F 78°F 59% 11 Scattered 97°F 90°F

1540 88°F 76°F 57% 11 Mostly 93°F 88°F

1600 88°F 76°F 57% 11 Mostly 93°F 88°F

°F = degrees Fahrenheit

^ = miles per hour 

*NOAA [2008]. Quality controlled local climatological data. National Oceanic and Atmospheric 

Administration, http://cdo.ncdc.noaa.gov/qclcd/QCLCD?prior=N. 

**NOAA [2011]. Heat index calculator. National Weather Service, National Oceanic and Atmospheric 

Administration, http://www.srh.noaa.gov/epz/?n=wxcalc_heatindex. 

***Bureau of Meteorology [2010]. Thermal comfort observations - web bulb globe temperature 

(WBGT). Australian Government, http://www.bom.gov.au/info/thermal_stress/#wbgt. 
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Appendix A

Live-fire Exercises: Interior and Exterior Evolutions

Interior Evolutions - Burn Building

The two-story burn building is located in the south east portion of the main building. It is constructed 

of steel with a concrete floor and measures 16 feet by 33 feet. There are 2 burn rooms downstairs and 

1 burn room upstairs along with attic space and a panel chop out on the roof. The building is equipped 

with a 10-foot by 10-foot exterior platform and stairway. The interior of the burn building is composed 

of 1-inch thick panels of Padgenite (crushed/milled calcium silicate).

The burn building fires is fueled by Excelsior. Excelsior is a shredded wood material that needs to be 

“fluffed” from its’ storage bales. Approximately one-fourth of a bale is used for each burn evolution. 

No other fuel (pallets or propane) was used.

During the burn building exercises, the instructors utilized an incident management system. Instructors 

rotate between the roles of Incident Commander, fire attack, RIT, and rehab. A staff member is 

assigned as pump operator while another instructor serves as proctor and evaluates the trainees’ 

performance.

The burn building training was broken into two components: (1) a guided walkthrough portion with no 

actual trainee fire fighting in the morning (the instructors performed the fire fighting as an example), 

and (2) afternoon rotation allowing the trainees to perform the live-fire suppression.

In general, trainees were divided into groups of 6, and then further divided into 2-person teams. Each 

team would rotate between the following 3 assignments: entry/attack, backup/ventilation, and RIT. 

All teams worked two separate fires; one downstairs and one upstairs. The assigned entry/attack team 

advanced the hoseline to the fire and perform either direct or indirect attacks as instructed. Although 

all teams wore wear full bunker gear with SCBA, only the entry/attack team was “on air.” The entry 

teams would rotate the nozzle person between the two (upstairs and downstairs) fires. During team 

assignment changes, short breaks of about 10 minutes were allowed, but PPE was not allowed to 

be doffed.

Before starting the live-fire training, coordination was established between the command, fire attack 

leader, RIT leader, interior safety, and ignition officer. At the appropriate time the fire would be lit by 

the ignition officer and the two-person fire attack team would enter the building.

If any problem is experienced, the evacuation signal would be sounded (3 blasts on the engine’s 

airhorn). At that point, all personnel inside the building would be instructed to evacuate the building 

and the staff would determine what action is required to correct the problem.
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Appendix A cont.

Exterior Evolutions

Hidden Wall Fire: The hidden wall prop consisted of an approximate 4-foot wall constructed of metal 

studs and a method of sliding sheetrock panels in front of the studs. Excelsior or hay was placed 

behind the sheetrock and ignited to produce a small, smoldering fire. For this rotation, the trainees 

were placed in teams of three. One trainee would carry the hoseline, another would carry a forcible 

entry tool (a Halligan® bar), and the third would carry salvage tools (a tub and a salvage cover). To 

complete this rotation, the fire had to be located, the salvage cover placed, the wall opened up, and the 

fire extinguished. While the group’s 1st team was participating, the second team of three was staged on 

the RIT hoseline wearing full bunker gear and SCBA and mask but not “on air.”

Fire Extinguisher Prop: The fire extinguisher prop consisted of an electrical box with a switch and a 

trough for flammable liquids. Once the trough liquid was ignited, the trainees sprayed the extinguisher 

on the electrical panel, flipped the switch to the “off” position, then continued to the trough and 

directed the extinguisher onto the fuel until the fire was extinguished. The group would work in teams 

of two for this exercise, and the remaining members would be on the RIT hoseline. All trainees would 

remain in full bunker gear and SCBA (mask in place but not on air) throughout this rotation.

Pallet/Dumpster Fire: At the pallet/dumpster fire rotation, trainees in two-person teams would wear 

full bunker gear with SCBA (mask in place but not on air). One team (mask in place and on air) would 

be on the nozzle, the second team (mask in place but not on air) would back them up, pulling slack, 

and the third team (mask in place but not on air) would be on the RIT hoseline. Each team would 

practice a “dry run” on extinguishing the simulated burning pallets and would move over to open the 

dumpster, stir the contents, and extinguish the dumpster fire. The teams would rotate positions until all 

teams completed this exercise. After practicing a “dry run,” each team would participate in actual livefire training, taking approximately 40 minutes per team rotation.

Car Fire Prop: The car fire consisted of a mockup of a car on fire. Trainees would wear full bunker 

gear and SCBA (mask in place and on air). Two-person teams would be formed, and each team would 

rotate personnel until each person had handled the hose nozzle. After practicing a “dry run” of this 

prop, teams would participate in actual live-fire training, taking approximately 40 minutes per team 

rotation.
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Appendix B

Instructor Positions, Responsibilities, and Qualifications

PSC coordinator is responsible for the following:

• plan and coordinate the entire training event

• ensure compliance with NFPA 1403 and other pertinent safety procedures

• coordinate instructors, assistants, and safety officer(s)

• verify training levels and competencies of instructors, assistants, and safety officers

• order consumables such as excelsior, propane, etc.

• ensure that training records are completed

Qualifications of the coordinator include: (1) Instructor I; (2) FFI or equivalent; (3) FFII if teaching 

any of the following: (a) FFII, (b) flammable liquids and gas firefighting [FLAG], or 

(c) liquefied petroleum gas [LPG] courses; and (4) Live-fire Train-the-Trainer certification.

Live-fire instructors are responsible for the following:

• present the classroom/skills training session

• pre-fire safety briefing

• ensure compliance with safety procedures

Qualifications for the live-fire instructors include: (1) Instructor I; (2) FFI or equivalent; 

(3) FFII if teaching any of the following: (a) FFII, (b) FLAG, or (c) LPG courses; and (4) Live-fire 

Train the Trainer certification.

Live-fire assistants (assigned by the live-fire coordinator) were responsible for the following:

• assist with live-fire training which could include water supply, igniter, prop assistant, etc.

Qualifications for a live-fire assistant included: (1) Structural Fire Fighter, FFI, or equivalent; (2) Livefire Train the Trainer certification; and (3) Ignition officers and igniters must also demonstrate their 

ability to the lead instructor.

Safety officers were assigned by the live-fire coordinator and were responsible for the following:

• ensure compliance with safety procedures

• ensure all instructors, assistants, and trainees have and wear NFPA compliant personal 

protective equipment and SCBA during training sessions

• establish “hot” zones with cones or other visible indicators

• intervene and stop operations when, in their judgment, a dangerous or unsafe condition exists

Qualifications for the safety officer were based on training, experience, and knowledge of NFPA 1500 

and NFPA 1403 as determined by the State Fire Service Training office.
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Appendix C

Incident Timeline Estimates for Members of the Blue Group

Hours:

0700: Instructors, staff, and trainees arrived at the State Fire Service Training PSC

0800: Introductions, Safety Briefing

0900: Reports to Rehab

1000: Walk-through and observation of interior live-fire suppression at burn building

1100: Hidden wall prop live-fire

Blue group trainee (Trainee B) suffers heat-related illness and transported to ED

1120: Second Blue group trainee (Trainee C) suffers heat-related illness (managed on-scene)

1130: Dumpster fire prop walkthrough

1200: Car fire prop walkthrough

1220: Lunch break

1330: Training resumes; assigned to Rehab

1445: Interior live-fire suppression at burn building

1600: Rest in rehab 

1630: Pallet/dumpster prop live-fire

1700: Car prop live-fire

1725: Training completed; trainees and instructors pick up hose and equipment

1815: Trainee A found in unconscious in bathroom stall
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Appendix D

Autopsy Findings

• Hyperthermia

o History of exercising in a hot environment

o “Vitreous electrolytes consistent with dehydration” (values not reported)

 Normal vitreous sodium 135–150 milliequivalents per liter

 Normal vitreous urea nitrogen 8–20 milligrams per deciliter [Rose and Collins 

2008]

o Generalized brain edema

• Hypertensive atherosclerotic cardiovascular disease (CVD) [Weiner and Baggish 2012]

o Cardiomegaly (enlarged heart) (heart weighed 560 grams [g]; predicted normal weight 

is between 327 g and 570 g as a function of gender, age, and body weight) [Kitzman et 

al. 1988; Silver and Silver 2001]

o Left ventricular hypertrophy (LVH) - Left ventricle and interventricular septum walls 

thickened (1.8 centimeters [cm] and 2.2 cm, respectively;

 Normal at autopsy is 0.76–0.88 cm [Colucci and Braunwald 1997];

 Normal by echocardiographic measurement is 0.6–1.1 cm) [Armstrong an 

Feigenbaum 2001]

• Coronary artery disease 

o Moderate (75%) focal narrowing of the left anterior descending coronary artery

o Mild (50%) focal narrowing of the right coronary artery

o No evidence of recent thrombus (blood clot in the coronary arteries)

• Normal cardiac valves

• No evidence of a pulmonary embolus (blood clot in the lung arteries)

• Obesity

• Blood tests for drugs and alcohol were negative

REFERENCES

Armstrong WF, Feigenbaum H [2001]. Echocardiography. In: Braunwald E, Zipes DP, Libby P, eds. 

Heart disease: a text of cardiovascular medicine. 6th ed. Vol. 1. Philadelphia, PA: W.B. Saunders 

Company, p. 167.

Colucci WS, Braunwald E [1997]. Pathophysiology of heart failure. In: Braunwald, ed. Heart disease. 

5th ed. Philadelphia, PA: W.B. Saunders Company, p. 401.

Kitzman DW, Scholz DG, Hagen PT, Ilstrup DM, Edwards WD [1988]. Age-related changes in 

normal human hearts during the first 10 decades of life. Part II (maturity): a quantitative anatomic 

study of 765 specimens from subjects 20 to 99 years old. Mayo Clin Proc 63(2):137–146, 

http://dx.doi.org/10.1016/S0025-6196(12)64946-5.

Rose KL, Collins KA [2008]. Vitreous postmortem chemical analysis. College of American 

Pathologists, NewsPath: News for the Pathology Community, December 2008, 

http://www.cap.org/apps/docs/newspath/0812/vitreous_postmortem_chemical_analysis.pdf.
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Silver MM, Silver MD [2001]. Examination of the heart and of cardiovascular specimens in surgical 

pathology. In: Silver MD, Gotleib AI, Schoen FJ, eds. Cardiovascular pathology. 3rd ed. Philadelphia, 

PA: Churchill Livingstone, pp. 8-9.

Weiner RB, Baggish AL [2012]. Exercise-induced cardiac remodeling. Progress in Cardiovascular

Diseases 54(5):380–386, http://dx.doi.org/10.1016/j.pcad.2012.01.006.
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Appendix E

Estimated Metabolic Heat Production (in kilocalories per minute) by Task Analysis during Interior 

Live Fire Prop, State Fire Service Training’s Professional Skills Center, OK [ACGIH 2015; ISO 2004;

NIOSH 1986]

Various Fire Fighter Positions kcal/min*

A. Body position and movement

Intermittent walking up/down/crawling 2.0 kcal/min

B. Type of work –

Both hands – heavy 3.5 kcal/min

C. Basal metabolism 1.0 kcal/min

Metabolic rate per minute 6.5 kcal/min

Metabolic rate per hour 390 kcal/hr

D. Multiply by the weight correction factor**: 390 kcal/hr x 1.9 = 741 kcal/hr

Total estimated metabolic rate = 741 kcal/hour
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Appendix F

Estimated Metabolic Heat Production (in kilocalories per minute) by Task Analysis during Exterior 

Hidden Wall Fire Prop, State Fire Service Training’s Professional Skills Center, OK [ACGIH 2015;

ISO 2004; NIOSH 1986]

Various Fire Fighter Positions kcal/min*

A. Body position and movement

Standing 0.6 kcal/min

B. Type of work –

Both hands – heavy 3.5 kcal/min

C. Basal metabolism 1.0 kcal/min

Metabolic rate per minute 5.1kcal/min

Metabolic rate per hour 306 kcal/hr

D. Multiply by the weight correction factor**: 306 kcal/hr x 1.9 = 581 kcal/hr

Total estimated metabolic rate = 581 kcal/hour
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Appendix G

Estimated Metabolic Heat Production (in kilocalories per minute) by Task Analysis during Exterior 

Fire Extinguisher Prop, State Fire Service Training’s Professional Skills Center, OK [ACGIH 2015;

ISO 2004; NIOSH 1986]

Various Fire Fighter Positions kcal/min*

A. Body position and movement

Standing 0.6 kcal/min

B. Type of work –

Both hands – light 1.5 kcal/min

C. Basal metabolism 1.0 kcal/min

Metabolic rate per minute 3.1 kcal/min

Metabolic rate per hour 186 kcal/hr

D. Multiply by the weight correction factor**: 186 kcal/hr x 1.9 = 353 kcal/hr

Total estimated metabolic rate = 353 kcal/hour
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Appendix H

Estimated Metabolic Heat Production (in kilocalories per minute) by Task Analysis during 

Pallet/Dumpster Fire Prop, State Fire Service Training’s Professional Skills Center, OK [ACGIH 2015;

ISO 2004; NIOSH 1986]

Various Fire Fighter Positions kcal/min*

A. Body position and movement

Standing 0.6 kcal/min

B. Type of work –

Both hands – light 1.5 kcal/min

C. Basal metabolism 1.0 kcal/min

Metabolic rate per minute 3.1 kcal/min

Metabolic rate per hour 186 kcal/hr

D. Multiply by the weight correction factor**: 186 kcal/hr x 1.9 = 353 kcal/hr

Total estimated metabolic rate = 353 kcal/hour
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Appendix I

Estimated Metabolic Heat Production (in kilocalories per minute) by Task Analysis during Car Fire 

Prop, State Fire Service Training’s Professional Skills Center, OK [ACGIH 2015; ISO 2004; NIOSH 

1986]

Various Fire Fighter Positions kcal/min*

A. Body position and movement

Standing 0.6 kcal/min

B. Type of work –

Both hands – light 1.5 kcal/min

C. Basal metabolism 1.0 kcal/min

Metabolic rate per minute 3.1 kcal/min

Metabolic rate per hour 186 kcal/hr

D. Multiply by the weight correction factor**: 186 kcal/hr x 1.9 = 353 kcal/hr

Total estimated metabolic rate = 353 kcal/hour

FOOTNOTES AND REFERENCES – APPENDICES E–I

*For a standard male worker of 70 kilograms (kg) (154 pounds) body weight and 1.8 m2 (19.4 ft2) 

body surface [NIOSH 1986].

**The weight correction factor (WCF) is used when employee weight plus personal protection 

ensemble and equipment weigh more than 154 pounds (lbs). The WCF is calculated by dividing the 

sum of the employee’s current body weight (BW) and the PPE plus equipment weight (EW) by 154 lbs 

[WCF = (BW + EW) ÷ 154 lbs]. Trainee A’s correction factor on May 31, 2008, was estimated to be 

(268 lbs + 30 lbs) ÷ 154 lbs = 1.9. 

ACGIH [2015]. Documentation of the threshold limit values® and biological exposure indices®, 7th ed. 

Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

International Organization for Standardization (ISO) 8996 [2004]. Ergonomics of the thermal 

environment – determination of metabolic rate. Geneva, Switzerland.

NIOSH [1986]. Criteria for a recommended standard: occupational exposure to hot environments, rev. 

Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and 

Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 

86-113.
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Appendix J

Estimating Wet Globe Bulb Temperature (WBGT)

From Temperature and Relative Humidity*

*Source: Bureau of Meteorology [2010]. Thermal comfort observations - web bulb globe temperature 

(WBGT). Australian Government, http://www.bom.gov.au/info/thermal_stress/#wbgt.