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Cadet Dies from Hyperthermia and Exertional Heat Stroke During 

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Executive Summary

On March 31, 2016, a 32-year-old male 

career fire fighter cadet (the Cadet) 

participated in SCBA (self-contained 

breathing apparatus) maze training inside 

a “survival house.” The training was the 

final day of a 3-day fireground survival 

program. He was wearing PPE (personal 

protective equipment) consisting of full 

turnout gear with SCBA (on-air). The 

Cadet was nearing the end of the course 

when he collapsed. A Mayday was called 

and the Cadet was removed from the 

building. 

CPR (cardiopulmonary resuscitation) was 

begun. Ambulance paramedics who were 

at the facility for training provided advanced life 

support (cardiac monitoring, intravenous fluids and

medications, and rescue airway). They also initiated 

active cooling measures because the Cadet’s core body temperature was 108.2°F (42.3°C). The Cadet 

was transported to the hospital’s emergency department (ED). Inside the ED, additional cooling 

measures were taken and advanced life support continued for 57 minutes. Resuscitation efforts were 

not successful and the Cadet was pronounced dead. 

The autopsy report listed “hyperthermia and dehydration” as the cause of death and stated “the exact 

cause of the hyperthermia is unknown.” NIOSH investigators concluded that the physical exertion of 

the training performed in full PPE/SCBA contributed to the Cadet’s hyperthermia and exertional heat 

stroke. 

Key Recommendations

NIOSH offers the following recommendations to help reduce the risk of heat stress-related injuries and 

fatalities among trainees and fire fighters at this and other fire departments across the country. 

• Ensure that a comprehensive rehabilitation program is in place and operating, which follows

recommendations in National Fire Protection Association (NFPA) 1584, Standard on the 

Rehabilitation Process for Members During Emergency Operations and Training Exercises. 

• Strengthen the heat stress program by implementing (or reinforcing) the following recommendations 

for all training courses: 

Photo. One of the interior entanglement areas 

in the survival house. (Photo by NIOSH.)
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Before training:

 Ensure that trainees are medically cleared by a physician knowledgeable about NFPA 1582, 

Standard on Comprehensive Occupational Medical Program for Fire Departments, including 

the physical demands of fire fighter training and the PPE used. 

 Educate/re-educate trainees on the importance of reporting off-duty injuries and medical 

conditions, to include use of medications or dietary supplements.

 Have onsite staff (e.g., paramedics) assess trainee risk for heat-related illness prior to strenuous 

training, to include any training in full turnout gear; consider use of a checklist or other

screening tool. 

 Ensure that trainees (and their instructors) are well-versed on NFPA 1584, to include 

recognizing early signs and symptoms of possible heat-related illness and understanding 

potential consequences if not promptly reported and treated.

During training:

 Ensure that onsite paramedics regularly monitor trainees for early signs and symptoms of heatrelated illness (overall appearance, mental status, vitals, etc.) at a frequency based on training 

duration, intensity, and other relevant factors. 

 Ensure that trainees remain well hydrated throughout all phases of physically demanding tasks.

After training:

 Ensure that trainees rehydrate during rehab to fully replace fluid losses from sweating. For 

multi-day 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].

 Solicit input from trainees and instructors about removing barriers (real or perceived) to 

reporting or seeking medical attention for signs/symptoms of possible heat-related illness. 

The following recommendations would not have prevented the Cadet’s death, but NIOSH investigators 

include them to address general safety and health issues:

• Ensure that training maze props or trailers used in SCBA confidence training have adequate safety 

features such as emergency egress panels, emergency lighting, ventilation, and a temperature 

monitoring system to measure the ambient temperature inside the maze.

• In addition to ice water immersion therapy, consider having a second rapid cooling method 

available that could be accessed quickly during strenuous training.

• Provide preplacement and annual medical evaluations for all fire fighters consistent with guidance 

in NFPA 1582.

• Provide fire fighters with medical clearance to wear SCBA as part of the fire department’s medical 

evaluation program. 

• Perform an annual physical performance evaluation (physical ability test) for fire fighters.

• Phase in a mandatory comprehensive fitness and wellness program to benefit all firefighters.
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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 fatality is 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 March 31, 2016, a 32-year-old male career fire fighter Cadet suffered hyperthermia during training 

and died. The U.S. Fire Administration notified NIOSH of this fatality on April 1, 2016. NIOSH 

contacted the affected fire department on April 4, 2016, to gather additional information and initiate 

the investigation. On April 27, 2016, two safety and occupational health specialists from the NIOSH 

Fire Fighter Fatality Investigation and Prevention Program and a physical scientist from the NIOSH 

NPPTL (National Personal Protective Technology Laboratory) visited the incident site for an on-site 

investigation. The SCBA worn by the Cadet was shipped to the NPPTL for evaluation.

During the investigation, NIOSH personnel interviewed the following people: 

 Fire Chief

 Executive Chief of Operations Response Command 

 Assistant Chief for Professional Development 

 Assistant Chief of Operations 

 District Chief for Professional Development 

 District Chief of Cadet Training

 Fire Department Liaison Captain

 Arson investigators 

 Cadet’s sister

 Cadet’s girlfriend

NIOSH personnel reviewed the following documents: 

 Fire department standard operating guidelines

 Fire department annual report for 2015 

 Emergency medical services (ambulance) report

 Hospital ED records

 Death certificate

 Autopsy report 

 Fire department medical evaluation records 

 Primary care physician records

 Fire department SCBA breathing air test records

 Cadet’s training records

 Witness statements
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Personal Protective Equipment (PPE)

The Cadet was wearing the full complement of PPE consisting of a station uniform, turnout coat and 

pants, gloves, boots, hood, helmet, and SCBA with an integrated Personal Alert Safety System 

(PASS).

The Cadet’s SCBA was evaluated in the NIOSH NPPTL and a summary report is enclosed as 

Appendix E. The SCBA was not found to be contributory to the fatality. At the training site, breathing 

air quality certificates were checked for the breathing air source. Breathing air quality was ruled out as 

a factor in the Cadet’s death. 

Weather Conditions

Although this incident occurred inside an air-conditioned fire training center survival house, weather 

information is provided for context [NOAA 2016]. Weather conditions the morning of the incident 

included an ambient temperature of 74°F (23.5°C), relative humidity of 93%, heat index of 75°F 

(24°C), and mostly cloudy skies (0753 hours). Weather conditions at 1200 hours on the two training 

days before the incident included temperature 76°F (24.4°C), humidity 85%, heat index 77°F (25°C), 

and mostly cloudy skies on March 31st; and 71°F (21.7°C), humidity 84%, heat index 72°F (22°C), 

and overcast skies on March 30th. 

Structure 

SCBA Maze and Prop Building Construction

Note: The following description of the SCBA maze, props, the maze structure, and subsequent building 

construction information is based on material provided by the fire department and the Texas State Fire 

Marshal’s Office.

The medical incident took place during training in a survival house (see photographs 1–5 and diagrams 

1–4 in Appendix A). The survival house was a standalone permanent structure (not a maze trailer). It 

was located on the fire department training site. Live fire is not used in the prop. A smoke generator 

was used to introduce a realistic atmosphere. The fire department reported that over 7,000 students 

have gone through the survival house since it was constructed in 2009. 

The building housed a training prep room with electronic monitors and seating for students, and a 

3,400-square foot SCBA maze course. It had climate control, emergency access, and lighting. The 

maze was designed to provide students with hands-on-training on how to navigate through 

entanglement hazards and build confidence in their SCBA and survival skills. The training prop had 

numerous elevation changes, entanglement challenges, confined areas, and mis-orientation rooms. 

Trainees watch an instructional video in the air-conditioned prep room before the evolution begins. 

Before entering the maze, trainees don the full complement of PPE, including SCBA. They have 30 

minutes to complete the course. Students are told to remove their 2nd stage regulator but keep their 

facepiece on if they run out of air while moving through the course.
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Investigation 

For a detailed timeline, see Appendix B. On Thursday, March 31, 2016, the final day of a 3-day 

fireground survival training program, the Cadet arrived at the training facility at 0600 hours. At 0700 

hours, the instructional day began. The topic of that day for the 48 trainees was the SCBA maze course

located in the survival house. At 0900 hours, the Cadet was in the staging area of the survival house. 

He was wearing his normal station uniform (t-shirt and pants). He complained to another cadet that he 

felt hot and he was observed to be sweating. He stood in front of an air conditioner vent to cool off. 

The thermostat in the area was set to 66°F (19°C). 

At 0912 hours, the first cadet entered the SCBA maze course. At 1015 hours, the Cadet was told to get 

ready to enter the course. He donned his PPE, including SCBA. At 1025 hours, the Cadet entered the 

course. He was the eighth trainee to enter during this evolution. He was wearing full PPE, including 

SCBA and facepiece (on-air). The Cadet was instructed to disconnect his mask-mounted regulator 

from the facepiece if he ran out of air, and continue through the course. He was given instructions to 

follow the hoseline to the exit. The Cadet acknowledged these instructions. 

From 1045 hours to 1100 hours, the Cadet advanced through the course. Several instructors had visual 

and verbal contact with him. He responded appropriately to questions and moved effectively through 

the course. At Station 5, the instructor checked each trainee’s orientation and fatigue level. If the 

trainee could not continue, the instructor removed him or her from the course. A total of 3 trainees had 

already been removed before the Cadet got to Station 5. The instructor questioned the Cadet. He 

responded appropriately to questions and was still breathing air from his SCBA. There were 4 other 

trainees were on the course at the same time. Another instructor opened an access door to give 

instruction to a different trainee. The Cadet saw the open door/light and moved toward it. The 

instructor told the Cadet to stay on the course and that he was only giving instruction to another 

trainee. The Cadet responded appropriately and continued on the course. The instructor thought the 

Cadet had the regulator connected to his facepiece. 

From 1107 hours to 1115 hours, an instructor saw the Cadet moving the hoseline and passing by the 

exit. The instructor reached into the window and pulled the hoseline to show the Cadet that he was on 

the right path. The instructor heard the Cadet moving and then heard the Cadet stop. A short time later 

the Cadet’s PASS alerted and then went into full alarm. The instructor called out to the Cadet and 

received no response. The instructor entered the course through the trap door. When the Cadet did not 

respond, other staff members were alerted that a fire fighter was down and a Mayday was called.

The Cadet was removed from the course and his PPE and SCBA were removed. An instructor noted 

that the Cadet’s SCBA regulator was disconnected from his facepiece. (According to instructors, it was 

believed that the Cadet had disconnected the regulator after passing Station 6). The Cadet was 

unresponsive, not breathing, and pulseless. He was hot to the touch. CPR was begun. A medical bag 

was retrieved and an AED (Automated External Defibrillator) was connected. No shock was advised 

and CPR continued. 

A medic unit at the academy for classroom training responded to the survival building at 1115 hours. 

Paramedics found the Cadet unresponsive, with CPR in progress. A King Airway® was placed. Tube 

placement was verified by capnography [AHA 2016]. An IV (intravenous) line was established and 

cardiac resuscitation medications were administered. An AED was placed, and advised not to shock. 

Ambulance 52, Engine 61, Squad 46, Paramedic Supervisor 17 (AS017), Paramedic Supervisor 36 
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(AS036), and PG710 were dispatched to assist. 

A cardiac monitor replaced the AED. Asystole was revealed and CPR continued. A second IV line was 

placed. The Cadet’s skin was hot. Cold packs were placed in his groin area to lower his body 

temperature. PG710, AS017, AS036, and Engine 61 arrived on-scene (1125–1130 hours). Ambulance 

52 and Squad 46 were cancelled. 

The Cadet’s core (rectal) temperature was 107.2°F (41.8°C). After about 20 minutes of CPR, the Cadet 

was moved for transport to the ED (1136 hours). En route, he was intubated. Tube placement was 

verified by capnography [Neumar et al. 2010]. His core temperature rose to 108.2°F (42.3°C). 

Additional attempts to cool the Cadet included cooled saline IV solution, wetting his skin, and fanning. 

Additional cold packs were placed in his axilla and carotid areas. His heart rhythm remained in 

asystole during transport. A repeat core temperature read 109°F (42.8°C). The medic unit arrived at the 

ED at 1151 hours. 

Inside the ED, advanced life support continued. Additional cooling with ice packs was performed. 

Resuscitation efforts continued for 57 minutes but were unsuccessful. An attempt was made to initiate

ECMO (extracorporeal membrane oxygenation, a technique that removes blood from the body and 

returns it after cooling and oxygenation) [Shiraishi and Yokota 2013]; however, this was not 

successful. The Cadet was pronounced dead at 1248 hours. 

Medical Findings

The death certificate and autopsy report listed “hyperthermia and dehydration” as the cause of death. 

Pertinent autopsy findings are listed in Appendix F. 

The Cadet’s past medical history was noted for the following: 

Hyperlipidemia

Diagnosed at his fire department pre-placement physical in September 2015. His screening results 

included an elevated total cholesterol level of 235 milligrams per deciliter (mg/dL) (desirable < 200), 

elevated triglycerides (223 mg/dL, normal < 150), slightly elevated LDL “bad” cholesterol (133 

mg/dL; desirable < 130), and normal HDL “good” cholesterol (57 mg/dL, desirable > 40) [NHLBI 

2005]. He was referred to his primary care physician for follow-up. 

Other Medical History

The Cadet sustained a shoulder injury in a minor motor vehicle accident approximately 6 weeks prior 

to this incident. He saw a private provider and received a prescription NSAID (nonsteroidal antiinflammatory drug) and an oral corticosteroid. He also took dietary supplements to aid his recovery. 

About 1 week before the incident, he finished the prescription medications and resumed exercising.

Physical Activity

The Cadet’s regular workouts were rigorous and consisted of aerobic and strengthening exercises. 

Typically, he wore his turnout gear during workouts and got very hot, and would drank large quantities 

of water before he exercised. The weekend before the incident, the Cadet ran in a 10-kilometer race. 

Two days before the incident, he trained with other cadets outdoors on exterior maze props. The day 

before the incident, he participated in a search and rescue drill with 4-person teams and complained to 

his roommate that he was “really hot” during the drill. That evening, the Cadet completed his exercise 

routine and told his roommate that he had “nailed” his workout. 
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Fire Department

At the time of the NIOSH investigation, the fire department consisted of 93 fire stations with 3,789 

career uniformed personnel. Its Emergency Response Division operates on a 24/72 work schedule, 

which equates to a 47.6-hour workweek, including a 24-hour debit day, which is worked 

approximately once every 36 days. 

The fire department serves 2.2 million residents in a geographic area of 656 square miles. It provides 

aircraft rescue fire fighting for two large commercial airports. It provides automatic aid with one career 

fire department and one volunteer fire department, which are located in entities within the 

municipality. The fire department is also part of a regional mutual aid pact that covers transportation 

emergencies in the greater metropolitan area.

The fire department operates a fire administration office, a fire marshal’s office, a fire training 

academy, an arson division, a logistics center, a fire apparatus maintenance shop, and a fire operations 

division. The fire Emergency Response Division consists of 93 fire stations, staffing 87 engine 

companies, 37 ladder or truck companies (including 5 tower ladders), 56 basic life support ambulances 

with one EMT/B fire fighter and one engineer operator per unit, 34 medic units (advanced life support 

with two paramedic/fire fighters per unit), 11 squads (non-transport advanced life support units staffed 

by two paramedics), 3 rescue companies (including one heavy rescue), and 3 shift safety officers. 

There are 23 districts or battalions in the city. The minimum staffing for each engine company, ladder 

company, and rescue company is an officer (senior captain or captain), an engineer operator, and two 

fire fighters. Each district is staffed with a district chief and an incident command technician.

The fire department is rated by the Insurance Services Office as a Class I fire department and is an 

internationally accredited department through the Commission on Fire Accreditation International. In 

2015, the fire department responded to 325,479 incidents (an average of 891 per day): 43,352 fire 

incidents and 282,127 emergency medical incidents. The average response time for the first unit on 

scene was less than 6 minutes. 

Employment and Training

The fire department requires all applicants to be 18 to 35 years of age, have a valid state driver’s 

license with two or fewer moving violations in the last 36 months, pass a written test, attend applicant 

orientation, have fingerprints taken, pass a candidate physical ability test (see Appendix C), pass a 

questionnaire/interview, pass a polygraph examination, and pass a background investigation, prior to 

receiving a conditional job offer. The new member must then pass a preplacement medical evaluation 

(components described below) and a drug screen. 

The fire department requires new “fire fighter/emergency medical technician” applicants to have 

completed 60 accredited transferable college hours with a grade of “C” or higher or have 2 years of full 

time (active duty) military service with an honorable discharge. The new member then enters the 9-

month fire fighter academy to be trained to the Basic Fire Fighter level and basic emergency medical 

technician (EMT/B). During the fire fighter academy, the candidate must pass 4 additional physical 

ability tests (see Appendix D). Additional training to the Fire Fighter 1 and 2 level is provided through 

continuing education and on-the-job training.
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The fire department requires new “certified fire fighter/EMT” applicants to have a Texas Commission 

on Fire Protection Certification – Basic Fire Fighter or higher certification, and complete 15 accredited 

transferable college hours with a grade of “C” or higher. 

The new member then begins a 15-month probation period. The member also enters a 9-month fire 

fighter academy to be trained to NFPA 1001, Standard on Fire Fighter Professional Qualifications

standards to include Fire Fighter 1, Fire Fighter II, Hazardous Materials Awareness, and Hazardous 

Materials Operations [NFPA 2013a]. In addition, the trainee must meet the requirements of National 

Incident Management System (NIMS) 100 Introduction to ICS; NIMS 200 Basic ICS; IS 700A The 

National Incident Management System, An Introduction; and IS 800B The National Response 

Framework, An Introduction. In addition to the fire fighter training, the fire fighter trainees receive 

emergency medical services EMT/B certification, which is a 150-hour curriculum.

After completing the academy, new employees work the following shifts: 24 hours on duty, 24 hours 

off, 24 hours on duty, 5 days off. Each month, members also work a “debit day” in addition to their 

regular shift. New members are assigned Phase 1: Two months with an engine company, followed by 

Phase 2: Two months with a truck company, and then Phase 3: Two months with emergency medical 

services. Upon completion of probation, the fire fighter trainee becomes a fire fighter. 

The fire department requires all Emergency Response Division fire fighters to receive 2 hours of 

continuing education units training, 1 hour of risk management training, and 24 hours of in-service 

training per month. The Texas State Fire Commission requires 20 hours of continuing education units 

per month and the Insurance Services Office requires 8 hours of continuing education units plus eight 

multi-company drills per month. 

The fire department conducts live fire training twice a year at the department’s fire academy. The live 

fire training is compliant with NFPA 1403, Standard on Live Fire Training [NFPA 2012a]. Each live 

fire training evolution uses four engine companies, two ladder companies, one medic unit, and a 

district chief.

The fire department provides a certification program for all emergency operators, which is a tested 

position. The fire academy provides the training for the 56-hour certification program, which complies 

with NFPA 1002, Standard for Apparatus Driver/Operator Professional Qualifications [NFPA 2014]. 

The fire department pays for the state certification process through the Texas State Fire Commission. 

The fire department provides an officer development program for members, which is part of the 

department’s career path, plus the opportunity to acquire a college degree. This process uses 

curriculum from the National Fire Academy; local community colleges, colleges, and universities; and 

continuing education programs. 

The Cadet had completed 5 months of the academy.

Medical Evaluations 

Preplacement Medical Evaluations

The fire department requires preplacement medical evaluations for all applicants. Components of this 

evaluation include the following: 

 Complete medical history
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 Physical examination (including vital signs)

 Pulmonary function test 

 Audiogram 

 Vision screen

 Complete blood count with lipid panel 

 Urinalysis

 Urine drug screen

The evaluation is performed by a physician contracted with the city. Once this evaluation is complete, 

the contracted physician makes a determination regarding medical clearance for fire fighting duties 

and forwards this decision to the city’s personnel director and the fire department. 

The Cadet had a preplacement medical evaluation when he joined the fire department in September 

2015. 

Annual/Promotional Medical Evaluations 

Promotional medical evaluations are required by the fire department. Annual medical evaluations are 

voluntary and are provided at no cost to the fire fighter through the fire department’s health insurance 

plan. The results of these evaluations are not shared with the fire department. 

Medical clearance to wear SCBA is not required. Members injured on duty must be evaluated by the 

worker’s compensation physician and the results are provided to city risk management, which makes 

the final determination regarding return to work. 

Wellness/Fitness Programs

Fitness equipment (strength and aerobic) is available in the fire stations. Members are encouraged to 

exercise 3 hours a week while on-duty. The fire department does not have a comprehensive 

wellness/fitness program as recommended by the International Association of Fire Fighters/ 

International Association of Fire Chiefs Wellness Fitness Initiative [IAFF and IAFC 2008]. 

The Cadet supplemented his academy fitness training by participating in a structured aerobic and 

strengthening program at a local gym. He was also a fitness trainer.

Discussion 

Heat Stress/Strain, Tolerance, Dehydration, Heat Illness, Heat Stroke

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

environment (air temperature, humidity), physical activity (metabolic heat), and protective 

clothing/PPE [NIOSH 2016]. The body thermoregulates itself by increasing blood flow from the 

warmer core out to the skin. This helps expel heat to the surrounding environment and facilitates the 

evaporation of sweat, which is the most effective way for the body to cool itself [Roberts and Wenger 

1979]. To support increased skin blood flow, the heart must pump faster and harder (cardiovascular 

strain). Thermal strain refers to an increase in deep body or core temperature (hyperthermia). If the 

body lacked the ability to sweat and increase blood flow to the skin, core temperature would rise 
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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. Only about half the variation 

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

tolerance can vary day-to-day even in the same person, because of physiologic factors (for example,

hydration, nutrition, fatigue, sleep, medications, underlying illness, etc.) [DOD 2003; NIOSH 2016]. 

Heat acclimatization is the process whereby the body develops improved tolerance to heat-exertion, 

which requires repeated exposure over the course of days to weeks [DOD 2003; NIOSH 2016]. Once 

acclimated, work output increases with less physiological strain (lowered heart rate and body 

temperature), lowering the risk of heat-related illness [DOD 2003; Moseley 1994]. A high level of 

aerobic fitness provides partial acclimatization, as metabolic heat from exercise confers physiological 

benefits similar to those from environmental heat [Nunneley and Reardon 2002; Tipton et al. 2008]. 

Dehydration. The rate of sweating is influenced by environmental heat, physical activity, 

clothing/PPE, and acclimatization [DOD 2003]. Once acclimated, the sweat rate increases to promote 

cooling, and fewer electrolytes are lost. Around 1 quart (liter) of sweat is lost during 1 hour of 

strenuous heat-exertion, which doubles if limited permeability PPE is worn (for example, turnout gear) 

[DOD 2003; Eglin et al. 2004]. Dehydration worsens hyperthermia and increases the risk of heatrelated illness. The reduced blood volume strains the heart, sweat production decreases, core 

temperature rises, endurance declines, and fatigue occurs earlier [Cheuvront et al. 2010; Sawka et al. 

1985]. 

Proactive replacement of fluid losses is important during exertion-heat stress, as thirst may not arise

until more than 2% of body weight is lost [Armstrong and Epstein 1999]. 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]. This rate of intake also 

approximates the stomach’s emptying rate of about 1.2 quarts per hour [Marzio et al. 1991]. If exertion 

will be prolonged (e.g., > 1 to 2 hours) and heavy sweating is likely, electrolyte-carbohydrate sports 

drinks are recommended to prevent dilutional hyponatremia [Montain and Cheuvront 2008; NFPA 

2015a]. 

Heat-related illness. Although adequate hydration, fitness, and acclimatization protect against heatrelated illness, they do not eliminate the risk [ACSM et al. 2007; DOD 2003]. The body’s ability to 

compensate for excess heat can become overwhelmed if evaporative cooling is inhibited by PPE and/or 

high humidity conditions [DOD 2003]. 

Exertional heat exhaustion is the most common heat illness among active people. It is characterized by 

physical exhaustion from excessive cardiovascular strain, where cardiac output cannot meet the 

demands of skin, muscle, and vital organs such as the heart and brain [Armstrong et al. 1997; DOD 

2003]. Other signs/symptoms may include profuse sweating, headache, weakness, light-headedness, 

tachycardia, etc. Hyperthermia, if present, may be mild to moderate (100.4 to 102.2°F / 38 to 39°C). 

Some individuals cannot tolerate this level of hyperthermia, while others (such as elite soldiers or 

athletes) may perform well at even higher temperatures [ACSM et al. 2007; Joy and Goldman 1968]. 

Once core temperature reaches 102.6°F (39.2°C), the likelihood of heat-exhaustion collapse is around 

25%, and as it approaches 104°F (40°C) the majority of people will experience a heat-related illness

[NIOSH 2016]. 
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Exertional rhabdomyolysis (rapid breakdown of skeletal muscle) can develop during strenuous 

exertion as a complication of heat stroke or as a separate injury [DOD 2003; NIOSH 2015]. Classic 

symptoms include muscle soreness, cramping, and weakness. In some cases, acute renal failure occurs

and hospitalization may be necessary to preserve kidney function. 

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 dysfunction, often with loss of 

consciousness [ACSM et al. 2007]. The brain is particularly sensitive to hyperthermia, but damage can

occur to multiple organs [Bouchama et al. 2005; Walter and Carraretto 2016]. 

Exertional heat stroke typically affects young, active people who are 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, in whom sweating has often ceased. Exertional heat 

stroke is a particular threat to fire fighters, who perform strenuous duties while wearing gear that traps 

their body heat [Goforth and Kazman 2015]. 

Exertional heat stroke can develop even during cool conditions that may be mistakenly considered 

“safe” [ACSM et al. 2007]. The time to reach severe hyperthermia can be short, ranging from about 30 

minutes to several hours [Rav-Acha et al. 2004]. Early signs/symptoms may be subtle or nonspecific, 

such as headache, nausea, clumsiness, or confusion (for example, failure to follow commands) [DOD 

2003; Epstein et al. 1999]. Many exertional heat stroke cases go unrecognized until they collapse. 

Mortality rates from studies of soldiers with exertional heat stroke range from about 4% to 22% [Carter 

et al. 2005; Rav-Acha et al. 2004; Shibolet et al. 1976]. Duration of hyperthermia prior to cooling 

affects prognosis more than peak core temperature [Shapiro et al. 1973]. Prompt immersion in cold/ice

water has been recognized as the most effective method to rapidly lower core temperature and improve 

outcomes [Casa et al. 2015; Leon and Bouchama 2015; McDermott et al. 2009]. 

Risk Factors for Heat-Related Illness/Exertional Heat Stroke

A number of predisposing factors for exertional heat illness have been identified (external and internal) 

[Abriat et al. 2014; Rav-Acha et al. 2004; USAPHC 2016]. These factors are discussed below as they 

relate to this incident.

External Risk Factors: 

Environment. The training took place inside an air-conditioned survival house. Environmental heat 

was not a factor in this incident. 

Repeated strenuous days. The incident occurred on the final day of training which followed 2 

consecutive days of other physical activities, consisting of outdoor maze training on day 1 and a search 

and rescue drill on day 2. The Cadet reported feeling over-heated during search and rescue training, but 

went on to complete a strenuous workout that night. 

The cumulative effect of heat stress is known to increase the risk of exertional heat illness on 

subsequent days, suggesting that heat stress can have enduring effects [Armstrong et al. 1990; Wallace 

et al. 2005]. Strenuous activity over multiple consecutive days is likely to have contributed to the heat 

stress experienced by the Cadet on the day of the incident. 
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PPE and heavy gear. The Cadet donned full PPE with SCBA 10 minutes before starting the 

evolution, and collapsed approximately 45 minutes into the course. 

Any protective clothing or equipment will compromise heat tolerance by adding weight and altering 

heat transfer [NIOSH 2016; White and Hodous 1987]. The features of PPE that protect against fire 

fighting hazards increase the risk of heat-related illness. The insulating layer of the turnout coat traps 

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

increases the work of breathing [Jones 1991], and the 40–50 pound weight of SCBA/PPE increases the 

metabolic workload [Haddam VFD 2013]. PPE/SCBA contributed to the Cadet’s heat stress. 

Exertion. Based on descriptions of the course, estimates from similar activities, and PPE/SCBA 

considerations, the estimated workload for maze training exceeds 7 METs (metabolic equivalents), 

which is considered a vigorous level of activity [Ainsworth et al. 2011; NFPA 2015a]. Maze training 

also had a time limit for successful completion, which would have contributed to its intensity. Prior to 

the Cadet’s collapse, instructors had already removed 3 out of 8 cadets in the evolution due to fatigue 

or disorientation. The metabolic workload and intensity of maze training contributed to the heat 

stress/strain experienced by the Cadet.

Internal (Personal) Risk Factors: 

The Cadet was young, not overweight, and he had no drug or recent alcohol use. His medical history

was not known to include any of the following risk factors: prior heat-related illness, underlying acute 

illness, chronic disease, or a skin disorder. 

Acclimatization. The Cadet had completed 5 months of training at the fire fighter academy, which 

included physical activity indoors and outdoors. (He was also fit, which partially acclimates the body 

to heat stress.) 

Lack of heat acclimatization was not a factor in this incident.

Fitness. The Cadet exercised regularly to maintain a high level of aerobic fitness and strength. 

Poor fitness was not a factor in this incident. 

Dehydration. Throughout the 3 days of training, cadets were briefed on preventing dehydration. 

Access to drinking water was not identified as a problem and the Cadet reportedly drank water during 

the training. However, approximately 1.5 hours before starting the physical portion of the maze 

training, the Cadet stood in front of an air conditioner and perspired heavily. The Cadet had reportedly 

worked out at the gym recently in his turnout gear and had gotten overheated. (Exercising in protective 

clothing does not improve acclimatization to exercise in the heat, and can in fact worsen dehydration 

because of increased sweating [Aoyagi et al. 1994; Windle and Davies 1996].) 

Laboratory findings at autopsy suggested the Cadet was dehydrated (e.g., mildly elevated 

concentrations of vitreous sodium and urea nitrogen). Dehydration is likely to have contributed to the 

Cadet’s heat stress. 

Sleep loss. Military studies have identified sleep deprivation as a risk for exertional heat stroke [Abriat 

et al. 2014; NEHC 2007; Rav-Acha et al. 2004]. This may be related to physiological effects such as 

decreased skin blood flow, reduced sweating, and changes in the secretion of cortisol (a stress 

hormone) [Abriat et al. 2014; Stephenson et al. 1988]. Studies in athletes have also revealed that risk of 
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heat stroke increases when experiencing multiple simultaneous stressors, such as reduced sleep

combined with a sudden increase in physical training and poor nutrition [ACSM et al. 2007]. 

In this incident, a witness stated that the Cadet did not appear rested when he arrived at the facility at 

0600 hours; apart from this, there was no indication that the Cadet was sleep deprived. It is unclear if 

sleep loss was a contributing factor. 

Fatigue. Fatigue increases the risk of exertional heat stroke [ACSM et al. 2007; Armstrong et al. 

1990]. Events in the days leading up to the Cadet’s collapse suggest he might have been fatigued on 

the day of the incident. He had completed 2 days of physically demanding fireground training before 

the incident, as well as a full workout the night before. Autopsy findings suggested dehydration, which 

can cause fatigue [Cheuvront et al. 2010; DOD 2003]. 

Although it cannot be known with certainty if the Cadet was experiencing fatigue the day of the

incident, events in the preceding days suggest this was likely. 

High motivation. Exertional heat stroke has been called the “illness of the over-motivated” and this 

has been recognized in cases involving soldiers and athletes [Abriat et al. 2014; Cleary 2007; Epstein 

et al. 1999; Lopez et al. 2011; Rav-Acha et al. 2004]. A strong desire to successfully complete a 

mission will compel some soldiers to continue pushing themselves despite symptoms of heat illness. 

Athletes, especially during competition, may ignore early warning signs or symptoms that would 

normally be protective. In other words, in the setting of heat stress, judgment may be impaired among 

those who are driven to succeed. 

The Cadet’s history showed a high degree of personal drive. He served in a reserve component of the 

U.S. Armed Forces and had a goal to join an elite unit known for intense training and discipline. He 

was a high school varsity athlete and continued his athletic involvement at the university level. He was 

self-disciplined to maintain an advanced degree of fitness. 

A high level of self-motivation is likely to have played a role in the Cadet attempting to complete the 

SCBA maze course despite feeling over-heated.

Alcohol and illicit drugs. Recent alcohol intake reduces heat tolerance due to its diuretic effect

[Serafin 1996]. Stimulant drugs such as cocaine increase body heat and cause vasoconstriction, which 

impairs heat elimination [Crandall et al. 2002]. 

Alcohol and illicit drugs were not factors in this incident. 

Medications and supplements. Approximately 1 week prior to the incident, the Cadet finished taking 

presciption medications. Based on information about drug half-lives, it is likely these medications 

would have been eliminated from his body by the day of the incident. 

The Cadet had been taking an energy supplement containing caffeine, amino acids, vitamins, and other 

ingredients. He reportedly did not take the supplement the day before or day of the incident. Caffeine 

is nearly eliminated about 24 hours after being consumed (elimination half-life of approximately 4 to 6 

hours) [Benowitz 1990]. Past concerns about caffeine and heat stress have related to its mild diuretic 

effect and potential for dehydration [Serafin 1996]. Recent reviews have not shown concern for 

dehydration or heat intolerance with moderate intake (for example, the equivalent of 2 to 4 cups of 

coffee a day) [Maughan and Griffin 2003; Roti et al. 2006; Zhang et al. 2015]. However, Armstrong et 

al. [2007] caution that more study is needed on newer low-volume, high-caffeine products that can
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deliver a large dose in a short period of time. The ingredients in energy supplements apart from

caffeine may also be of concern. Following increased reports of adverse events from these 

supplements, the U.S. Food and Drug Administration issued a warning that energy supplements “are 

not substitutes for rest or sleep” [FDA 2012]. FDA recommends checking with a physician before 

starting any dietary supplement, as adverse effects can occur when combined with other supplements 

or medications [FDA 2016]. 

The medical examiner’s report stated, “The role that these supplements and medications may have 

played is uncertain.” 

Summary of Predisposing Factors: 

The Cadet was showing signs of feeling over-heated prior to starting training. The reasons for this are 

not known. Once the evolution began, he was exposed to multiple sources of heat stress--physical 

exertion, encapsulating turnout gear, SCBA, and the weight of the PPE/SCBA. He had evidence of 

dehydration, which can worsen heat strain. Heat stress from the days leading up to the incident may 

have also been a contributing factor. 

Recommendations 

NIOSH offers the following recommendations to help lower the risk of heat stress-related injuries and 

fatalities among trainees and fire fighters at this and other fire departments across the country.

Recommendation #1: Ensure that a comprehensive rehabilitation program is in place and 

operating, which follows recommendations in NFPA 1584 (Standard on the Rehabilitation Process 

for Members During Emergency Operations and Training Exercises).

Discussion: Rehabilitation operations should be provided in accordance with fire department standard 

operating procedures, NFPA 1500 (Standard on Fire Department Occupational Safety and Health 

Program), and NFPA 1584 [NFPA 2013b, 2015a, 2018b]. Rehabilitation efforts should include the 

following: 

1. Relief from climatic conditions

2. Rest and recovery

3. Active and/or passive cooling or warming as needed for incident type and climate conditions 

4. Rehydration (fluid replacement) 

5. Calorie and electrolyte replacement as appropriate for longer duration incidents 

6. Medical monitoring

7. Member accountability

8. Release [NFPA 2015a].

During this training, cadets were performing strenuous tasks while wearing full turnout gear with 

SCBA. However, medical monitoring was not performed. 

Recommendation #2: Strengthen the heat stress program by implementing/reinforcing the following 

recommendations for all training courses: 

Before training:

• Recommendation #2a: Ensure that trainees are medically cleared by a physician

knowledgeable about NFPA 1582 (Standard on Comprehensive Occupational Medical 
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Program for Fire Departments), including the physical demands of fire fighter training and 

the PPE used.

Discussion: The fire department should ensure that evaluating physicians are familiar with the 

strenuous tasks and physiological, emotional, and environmental demands of fire fighting and 

training, the hazards encountered, and the required PPE. Information should also be made 

available to private physicians who deliver care to off-duty trainees. In addition to NFPA 1582 

guidance, a new resource (concise handout) is available to help private providers make 

informed decisions regarding fire fighter/trainee medical fitness. The Healthcare Provider’s 

Guide to Firefighter Physicals addresses routine screening as well as the specific physiological 

demands and health risks fire fighters and trainees face as “tactical athletes” [IAFC 2016]. 

• Recommendation #2b: Educate/re-educate trainees on the importance of reporting off-duty 

injuries and medical conditions, to include use of medications or dietary supplements. 

Discussion: The training facility standard operating guide requires all trainees to “report to their 

instructor any condition that might impair their ability to participate in scheduled training 

activities.” In addition, “all cadets shall immediately report, or arrange notification for, any 

injury that occurs on their personal time that is likely to interfere with their training 

responsibilities” [TDI 2016]. The fire department discourages supplement use and provides 

each cadet with a two-page document, “The Dangers of Dietary or Performance Enhancing 

Supplements.” Each cadet is required to read and sign the policy. 

Trainees should be educated/reeducated about the importance of disclosing off-duty injuries, 

illness, treatment, etc. because of potential adverse consequences to their personal safety and 

that of others. Trainees should be reassured that disclosure will not automatically disqualify 

them from participation in training. 

• Recommendation #2c: Have onsite staff (e.g., paramedics) assess trainee risk for heat-related

illness prior to strenuous training, to include any training in full turnout gear; consider use 

of a checklist or other screening tool. 

Discussion: A systematic pre-participation assessment can assist onsite staff to better assess 

each trainee’s suitability for training and identify any recent issues (illness, injury, medications, 

sleep deprivation, etc.) or ongoing factors (obesity, chronic disease, a tendency to be stoic, etc.) 

that may require closer monitoring and further evaluation. 

Screening strategies from other groups may be helpful to develop a checklist or other screening 

tool specific to fire fighter trainees. For example, the U.S. Army created a “Risk Assessment

Worksheet” to assess soldiers prior to missions or tasks that would require physical exertion in 

hot conditions [TRADOC 2016]. The assessment takes into account risk considerations such as 

projected workload, the workload on the previous 2 days, the number of days acclimated to the 

heat, hours slept during the past 24 hours, etc. For athletes wanting to play competitive sports,

an expert panel developed a “Heat-Illness Screening Instrument” for athletic trainers to use 

when conducting pre-participation sports physicals. The instrument includes a brief 

questionnaire, several baseline measures (BMI, urine specific gravity), and a scoring system to 

estimate each athlete’s level of risk [Eberman and Cleary 2011]. 
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• Recommendation #2d: Ensure that trainees (and their instructors) are well-versed on NFPA 

1584, to include recognizing early signs and symptoms of possible heat-related illness and 

understanding potential consequences if not promptly reported and treated. 

Discussion: It is important for trainees and instructors to be vigilant for early signs and 

symptoms of excessive heat strain or heat-related illness, which may be subtle to detect and 

may be overlooked or ignored by trainees who are highly motivated to perform well. Trainees 

should be encouraged to promptly report issues for their own safety and that of others, and 

should be reassured that doing so will not automatically disqualify them from participation in 

training. 

During training:

• Recommendation #2e: Ensure that onsite paramedics regularly monitor trainees for early 

signs and symptoms of heat-related illness (overall appearance, mental status, vitals, etc.) at 

a frequency based on training duration, intensity, and other relevant factors.

Discussion: The fire department standard operating guide 6.2G states, “Training instructors 

shall be responsible for continuous monitoring of all participating personnel for signs and 

symptoms of heat and cold stress.” Emergency medical equipment (basic life support and an 

AED) were readily available and used. The instructors closely watched the cadets during each 

evolution but did not take vital signs or screen for signs/symptoms. 

Prior to each evolution that is physically demanding or conducted in full turnout gear, each 

trainee should be formally assessed to determine his or her suitability to continue training, as an 

enhanced margin of safety. Obtaining vital signs before training can be useful as part of the 

initial screening, as well as providing a set of baseline values to compare against subsequent 

assessments. 

• Recommendation #2f: Ensure that trainees remain well hydrated throughout all phases of 

physically demanding tasks.

Discussion: Specific recommendations on fluid intake to prevent dehydration during physical 

exertion are outlined in the NFPA and NIOSH documents below. 

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

Training Exercises, NFPA 1584 [NFPA 2015a]. 

 Criteria for a Recommended Standard: Occupational Exposure to Heat and Hot 

Environments, NIOSH Publication No. 2016-106 [NIOSH 2016]. 

 Evaluation of Heat Stress, Heat Strain, and Rhabdomyolysis During Structural Fire 

Fighter Training, NIOSH Health Hazard Evaluation Report 2012-0039-3242 [NIOSH 

2015]. 

After training:

• Recommendation #2g: Ensure that trainees rehydrate during rehab to fully replace their 

fluid losses from sweating; for multi-day exercises, encourage trainees to increase fluid 

intake during time away from training to reduce the risk of dehydration on subsequent 

training days [NIOSH 2015].
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Discussion: Fluid losses can accumulate throughout the course of training that takes place over 

consecutive days, in addition to fluid losses that occur during off-duty activities. Encourage 

trainees to increase their intake of fluids during time away from training (off-duty hours, rest 

days) while avoiding drinks containing high amounts of caffeine or sugar, and alcohol [NIOSH 

2015]. 

• Recommendation #2h: Solicit input from trainees and instructors about removing barriers 

(real or perceived) to reporting or seeking medical attention for signs/symptoms of possible 

heat-related illness.

Discussion: Some of the best “eyes and ears” for the baseline functioning, health status, and 

well-being of trainees may be those who know them best, e.g., fellow trainees. However, 

trainees may be reluctant to report issues about themselves or fellow trainees out of concern for 

the potential impact this could have on training progression. Gaining awareness of any 

reluctance to report health or safety concerns is an initial step in understanding the barriers so 

that they can be minimized or removed. 

Recommendation #3: Ensure that training maze props or trailers used in SCBA confidence training 

have adequate safety features such as emergency egress panels, emergency lighting, ventilation, and 

a temperature monitoring system to measure the ambient temperature inside the maze.

Discussion: Some training props (such as an SCBA training maze) contain confined space areas for 

skill building of fire fighters by restricting the maneuvering/working area of the fire fighter. Combined 

with reduced visibility and other conditions designed to simulate fireground conditions, these props 

challenge the fire fighters and improve their skills and confidence in using SCBA. Many of these 

training mazes are designed and constructed by fire departments and may not possess all of the necessary safety features to respond to medical emergencies of users. Although no fire or smoke conditions 

are introduced into these training maze props, fire fighters have experienced serious medical conditions 

while inside the props and have had to be extricated before treatment could be rendered. Extricating a 

fire fighter who has suffered a debilitating medical condition inside a severely restricted space is 

difficult and can be time consuming and labor intensive. Emergency egress panels that would allow for 

easy removal of fire fighters experiencing a medical event should be located inside the confined space 

areas. Emergency lighting should be provided for users and rescuers. The fire fighters often have PPE, 

SCBA, and other equipment that may have to be disentangled in order to remove them, and emergency 

lighting will aid in the extrication and removal. Many training mazes are outdoor semi-permanent 

trailer designs that are exposed to temperature extremes. A temperature monitoring system inside the 

training maze would allow the instructors to monitor temperature extremes and adjust the training 

accordingly. Ventilation of training mazes should be used to control the temperatures. Additional 

information concerning training props can be found in NFPA 1402, Guide to Building Fire Service 

Training Centers [NFPA 2012b]. 

In this incident, the SCBA survival house prop was well designed with air conditioning and lighting 

throughout. It contained a preparation room (staging area with chairs for students) and was well staffed 

with adequate instructors throughout the survival house. Once the students entered the course, 

instructors could monitor them throughout the prop. Trap doors were located throughout the maze that 

the instructors could use to access students throughout the prop. However, there was no emergency 

lighting. Emergency lighting is important in the event of an emergency on the survival course. Other 
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students and instructors can immediately take actions in the event an emergency activation of lighting 

is switched on and audible instructions given. 

The Cadet experienced a medical condition inside the training maze and had to be removed before 

medical assistance could be provided. When he experienced the medical condition, he was in a portion 

of the training maze that was immediately accessible to the instructors through trap doors and he was 

removed and treated.

The following recommendations would not have prevented the Cadet’s death, but NIOSH investigators 

include them to address general safety and health issues.

Recommendation #4: In addition to ice water immersion therapy, consider having a second rapid 

cooling method available that could be accessed quickly during strenuous training.

Discussion: The Cadet presented in acute circulatory failure, which may be attributable to myocardial 

damage from profound hyperthermia and has poorer prognosis [Drezner et al. 2007; Zahger et al. 

1989]. Ice water immersion therapy, AED, and paramedics were available on-scene. Since the Cadet 

was in cardiac arrest, resuscitation and transport to the ED were a priority. Although emergency 

medical services and ED personnel applied cold packs and administered cooled IV fluids, these 

methods are not very effective to rapidly lower core temperature [ACSM et al. 2007; Binkley et al. 

2002]. Immersion in ice water, however, may not be feasible when resuscitation or other lifesaving 

interventions are required at the same time. Alternative cooling methods have been recommended by 

others. For example, when heat stroke victims must be positioned on a backboard or stretcher for 

delivery of CPR or other lifesaving interventions, the U.S. military recommends placing iced sheets 

over the body coupled with fanning [DOD 2003; TRADOC 2016]. For similar situations, a multidisciplinary athletic task force recommends applying ice water towels to the head, trunk, and 

extremities combined with application of ice packs to the neck, axillae, and groin [Drezner et al. 2007]. 

For an extra margin of safety during arduous training, it is recommended that an additional rapid 

cooling method be available, so that life support and cooling measures can be administered at the same 

time. 

Recommendation #5: Provide preplacement and annual medical evaluations for all trainees/fire 

fighters consistent with guidance in NFPA 1582. 

Discussion: Preplacement and annual evaluations are performed to determine a fire fighter’s or 

trainee’s medical ability to perform duties without presenting a significant risk to the safety and health 

of himself/herself or others. Medical evaluations should be consistent with NFPA 1582 

recommendations [NFPA 2013c, 2018a]. Guidance is also available in The Healthcare Provider’s 

Guide to Firefighter Physicals, which assists private physicians to provide annual occupational exams 

for fire fighters [IAFC 2016]. 

At the time of the site visit, annual medical evaluations for fire fighters were voluntary and were

provided through the department’s health insurance plan. The fire department’s preplacement exam did 

not include a chest x-ray or resting 12-lead electrocardiogram (EKG), which NFPA 1582 recommends 

for trainees (Annex A.6.1.2) [NFPA 2018a]. 
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Recommendation #6: Provide fire fighters with medical clearance to wear SCBA as part of the fire

department’s medical evaluation program. 

Discussion: The Occupational Safety and Health Administration (OSHA) respiratory protection standard 

requires that private industry employers provide medical evaluations and clearance for workers who use 

respirators to make sure they are medically fit to tolerate the additional physical and mental stress [29 CFR 

1910.134; OSHA 2012]. This requirement extends to public workers in states that operate their own OSHAapproved occupational safety and health plans [OSHA no date]. Texas does not operate a state plan, so

departments are not mandated to clear fire fighters for SCBA use. However, NIOSH investigators 

recommend that fire departments voluntarily provide clearance to enhance fire fighter health and safety. 

Recommendation #7: Perform an annual physical ability evaluation (physical ability test) for fire 

fighters.

Discussion: Fire departments should determine the physical ability requirements for members who 

engage in emergency operations, as outlined in NFPA 1500, Standard on Fire Department 

Occupational Safety and Health Program [NFPA 2013b, 2018b]. This helps ensure that fire fighters 

are physically capable of carrying out tasks required for structural fire fighting, and it is recommended 

that fire fighters be evaluated and certified on an annual basis [NFPA 2013b, 2018b]. 

Recommendation #8: Phase in a mandatory comprehensive fitness and wellness program to benefit 

all fire fighters.

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

factors and improve aerobic 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, and in Firefighter Fitness: A Health and Wellness Guide [IAFF and IAFC 2018; NFPA 

2015b; Schneider 2010]. Worksite health promotion programs have demonstrated cost effectiveness by 

increasing productivity, reducing absenteeism, and decreasing the number of work-related injuries and

lost workdays [Aldana 2001; Stein et al. 2000]. Health promotion programs in the fire service have 

improved cardiovascular risk factors and fitness levels, with mandatory programs showing the greatest 

benefit [Blevins et al. 2006; Dempsey et al. 2002; Womack et al. 2005].

The fire department has an outstanding voluntary wellness/fitness program. However, NIOSH 

recommends a formal, structured program to ensure all fire fighters receive the benefits of a health 

promotion program. In addition, during exercise time, fire fighters should be taken out of service to 

ensure uninterrupted participation. 

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Investigator Information

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

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

and the Trauma LODD Investigations Team and National Personal Protective Technology Laboratory 

located in Morgantown, West Virginia. Mr. Tommy Baldwin (MS) led the investigation and coauthored 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. Mr. Steve Miles is a Safety and Occupational Health Specialist and a 

retired Battalion Chief of Safety with the Virginia Beach Fire Department and contributed to the 

report. Dr. Wendi Dick, Medical Officer/Team Lead for Cardiac and Medical LODD Investigations, 

provided medical consultation and contributed to the report. Mr. Jay Tarley is a Physical Scientist with 

the National Personal Protective Technology Laboratory and contributed to the report. 
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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 medical LODDs that have 

occurred in SCBA maze trailers. Below are links to other fatality investigations by NIOSH that 

involved this type of 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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Appendix A 

Survival House Photographs and Diagrams

This appendix includes photographs of the survival house and various props. Diagrams of the interior 

layout of the survival house are also displayed. 

Photo 1. Survival house exterior. (Courtesy of TX State Fire Marshal’s Office.)
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Photo 2. Exterior props that the students use to build their skills before the survival house. 

(NIOSH photo.)
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Photo 3. Entanglement prop inside survival house. (NIOSH photo.)
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Photo 4. SCBA skills prop showing fire fighter profiling SCBA cylinder to pass through hole.

(NIOSH photo.)
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Photo 5. SCBA skill house (instructors can monitor progress by openings in interior walls). 

(NIOSH photo.)
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Diagram 1. Survival house. (Courtesy of fire department arson bureau.)
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Diagram 2. Survival house. (Courtesy of fire department arson bureau.)
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Diagram 3. Survival house. (Courtesy of fire department arson bureau.)
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Diagram 4. Survival house. (Courtesy of fire department arson bureau.)
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Appendix B 

Incident Timeline

This timeline provides the general sequence of events according to recorded radio transmissions. 

Times are approximate and were obtained from the state fire marshal’s office report, witness 

interviews, and other available information. Some of the times have been rounded to the nearest 

minute. This timeline is not intended, nor should it be used, as a formal record of events. 

Incident and 

Fireground Conditions

Time Response and

Fireground Operations

Cadet arrived at training facility 0600 Third and final day of survival training 

program 

Instructional day began 0700 Survival house course

Cadet was inside survival house in the 

staging area in station dress, not wearing

PPE

0900 Survival house was air conditioned;

Cadet complained to another cadet that 

he was hot and sweaty and then moved 

to stand in front of air conditioning vent 

Other cadets began the survival house 

course 

0912

Cadet was told to gear up in PPE and 

SCBA and prepare to enter course

1015

Cadet donned PPE and SCBA and 

entered the course in the survival house 

(on-air)

1025 Cadet was the 8th student in the rotation 

on this evolution 

1025 Cadet was instructed to follow hoseline 

through the course and if he ran out of 

air, to disconnect the 2nd stage from the 

facepiece and continue the course

Cadet continued to advance through 

obstacles and entanglement props 

successfully

1045–1100

Instructors had visual and verbal 

communications with the Cadet 

1045–1100 Cadet responded correctly to instructors’ 

prompts and was moving through the 

course well
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Incident and 

Fireground Conditions

Time Response and

Fireground Operations

Cadet continued through course and at 

station 5 is questioned by instructor for 

orientation and fatigue 

1045–1100 Instructor removed 3 students from the 

course at this station prior to seeing 

Cadet; Cadet responded appropriately to 

instructor’s prompts and was breathing 

air from his SCBA

4 other cadets were on the course during 

this time; instructor opened an 

emergency access door to give 

instruction to one other cadet 

1045–1100 Cadet started to move toward light from 

the open door and was told to stay on the 

course; Cadet was on air (2nd stage 

connected)

Cadet passed instructor at course exit; 

instructor pulled on hoseline indicating 

to Cadet that he was on the correct path

1107–1115 Cadet passed the exit point and moved 

up and down the wall area; instructor 

heard Cadet stop and a short time later 

heard Cadet’s PASS alarm 

Instructor called out to Cadet and 

receiving no response entered the course 

through a trap door, alerted other 

instructors, and called a Mayday

Another instructor entered the course to 

assist

1107–1115

Cadet was removed from course and his 

PPE and SCBA removed 

Cadet is breathless and pulseless

1107–1115 CPR was initiated, AED was applied, 

and airway was placed

On-site FD ALS rescue unit was 

summoned 

1115–1116 ALS administer patient care; Cadet was 

in asystole with a rectal temperature of 

108 degrees F. Active cooling measures 

were initiated with cold packs placed in 

groin and arm pits and cooled IV fluids 

Cadet was transported to hospital 1136 Cadet’s temperature was 109 degrees

Medic unit with Cadet arrived at 

hospital 

1151 Patient care was transferred to 

emergency department staff; ALS, 

cooling measures, and CPR were 

continued 

1248 Cadet was pronounced dead 
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Appendix C

Candidate Physical Ability Test (CPAT)

The CPAT consists of two separate components. The first component is a series of tasks designed to 

assess important physical abilities necessary for effective job performance as a fire fighter. The second 

component is a 1.5-mile run. The following section describes both components of the physical ability 

test and offers information to assist the candidate in preparing. 

Component 1: Job Simulation Tasks

The first component of the test contains five job-simulation events that will be timed in a continuous 

series. These events include:

• Ladder Raise

• Stair Climb With Equipment

• Hoseline Hoist 

• Equipment Carry 

• Victim Rescue (dummy drag)

The following guidelines apply to this component of the CPAT: 

• Applicants must wear a self-contained breathing apparatus (SCBA), excluding the facepiece and 

low-pressure hose, for all elements of the job simulation component. The SCBA weighs 

approximately 20 pounds. 

• Applicants are strongly encouraged to wear athletic shoes (sneakers) and appropriate clothing for 

physically demanding work. You will be performing physical acts that demonstrate strength, 

agility, and endurance, and it is important to be outfitted in attire that does not hinder your 

performance. During the CPAT, you may get dirty and/or wet from maneuvering through the 

exercises. Plan your dress accordingly.

• Protective gloves are optional and it is the candidate’s choice whether or not to use gloves. You 

may bring your own gloves, kneepads, etc. to use; however, the testing authority reserves the right 

to inspect all equipment, and to disallow equipment, to ensure that its use does not affect the fair 

and impartial administration of the CPAT. 

• All five elements of this component of the CPAT will be timed in a series. The test has a cutoff 

time and failure to complete the course in the allowed time will result in disqualification.

• You must not run during the test. Running is not permitted on a working fireground, and it will not 

be allowed during this test. Failure to heed a first warning not to run may result in disqualification. 

Running is defined as any time both feet are off the ground at the same time while you are 

advancing on the course. You may move as fast as you like, while remaining safe on the stair climb 

stations, as it is not technically possible to run during these components. 
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• You should hit every stair going up and coming down while climbing the stairs. You may move as 

quickly as you like and are encouraged to use the handrails as needed.

• Test monitors will be assigned to time you while on the course. It is acceptable to ask the test 

monitor questions concerning course rules and layout prior to beginning the course and while on 

the course.

• You will be allowed as much time as needed to complete each individual component of the CPAT 

within the maximum allotted time. Should you perform one of the components incorrectly, the test 

monitor will guide you as to how to correct your actions or to perform the component again. Pay 

careful attention to the instruction of the test monitor and ask for clarification when needed. 

• Unnecessarily dropping, throwing, or other intentional misuse of any of the testing props will be 

grounds to disqualify a candidate. 

The following provides a description and preparation information regarding each of the five events 

contained in the first component of the CPAT. 

1. Ladder Raise. The candidate will raise the fly section of a 24-foot extension ladder using the rope 

(halyard). The ladder is secured to the rails of the tower staircase. The candidate will use a hand-overhand technique to extend the fly section of the ladder until the ladder is fully extended. The candidate 

will then lower the fly section down using a hand-under-hand technique. If the candidate loses control 

of the halyard (e.g., the rope slips through hands), he/she will be required to perform the event again. 

While raising and lowering the ladder, the candidate’s feet must remain in a 3-foot-by-3-foot box that 

is painted on the ground. 

Preparation: To simulate the ladder raise exercise, you can tie a rope securely to a weighted bag and 

place the rope over a sturdy horizontal bar that is eight to ten feet above the ground. Then you can use 

the same movements as you would in the ladder raise to bring the weight to the top of the bar and 

slowly lower it back to the ground. 

2. Stair Climb. The candidate will climb up to and back down from the 7th floor of the training tower 

(6 flights of stairs) while carrying a bundled section of 21⁄2-inch hoseline that weighs 35 pounds. Before 

entering the tower, the candidate will pick up the bundled hose pack. The candidate must carry this 

hose pack without dragging it. The candidate should hit every stair going up and coming back down 

the staircase. When the candidate reaches the 7th floor, he/she will place his/her feet on the landing 

and then turn around and descend the stairs. The candidate may use the handrails and may move as fast 

as he/she chooses on the stairs. Once the candidate exits the tower, he/she should set the hose pack on 

the ground. 

Preparation: This station assesses muscular and cardiovascular endurance. You may practice for this 

station by ascending and descending stairs while carrying approximately 55 pounds of weight (SCBA 

plus hose pack). 

3. Hose Hoist. The candidate will ascend to the third floor of an outdoor staircase, use a rope to hoist a 

rolled-up section of hoseline up to and back down from the third floor, and then descend the staircase. 

If the candidate loses control of the rope (e.g., the rope slips through hands), he/she will be required to 

perform the event again. While raising and lowering and hose roll, the candidate’s feet must remain in 

a box that is painted on the ground on the 3rd floor landing. 
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Preparation: To simulate the hose hoist, you can tie a rope securely to a weighted bag and place the 

rope over a sturdy horizontal bar that is eight to ten feet above the ground. Then you can use the same 

movements as you would to reel in a load attached to the rope. The weight of the hoseline is 

approximately 35 pounds. 

4. Equipment Carry. The candidate will carry a box weighing 75 pounds for a distance of 100 feet. The 

candidate will pick up the box off a 2-foot platform, carry the box for 50 feet around a cone and back 

to the starting location, and place the box on top of a 3-foot platform. The weighted box simulates the 

weight of a hydraulic power plant. You may set the box down at any time to rest, but may not drag or 

push the box – it must be carried.

Preparation: This station assesses core body strength, grip strength, and overall cardiovascular 

endurance. You may prepare for this event by carrying a 75-pound object for a distance of 100 feet. 

5. Victim Rescue (Dummy Drag). The candidate will drag a human form dummy weighing 165 pounds 

(weight of dummy and clothing) for 25 feet, around a barrel/cone and then back across the starting 

point for a total distance of 50 feet. The candidate will drag the dummy using the pull harness attached 

to the dummy or by placing his/her elbows under the armpits of the dummy. In order to complete this 

station, the candidate and the dummy must both completely cross the finish line. 

Preparation: This station assesses lower body strength and endurance. You may prepare for this event 

by dragging a weighted object using a rope. 

The five simulation events are timed in a series. Any candidate that completes the course in 6 minutes 

and 40 seconds (6:40) or less will pass this first component of the CPAT. 

Component 2: 1.5-Mile Run

Assuming the candidate successfully completed the first component of the CPAT, he/she will be 

afforded a rest period of approximately 15 to 20 minutes. After this time, the candidate will run 1.5 

miles. The 1.5-mile run must be completed in 15 minutes (15:00) or less to pass the CPAT. 

The 1.5-mile run is cardiovascularly demanding. In order to prepare for this component, you should 

run 1.5 miles multiple times and time yourself to ensure that you can achieve the necessary time.
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Appendix D

Academy Candidate Physical Ability Tests (PAT)

Grading

Trainees must obtain a minimum score of 70% on each Physical Ability Test. Failure to obtain a 70% 

will result in a retest. If upon retest the trainee passes that portion of the Physical Ability Test, the 

trainee will be given the minimum passing score (70%) for that portion of the test. The total number of 

Physical Ability Tests will be averaged for a final grade standing. The Training Officer will provide 

specific information regarding each portion of the Physical Ability Tests.

PAT #1 will be given approximately one month into the training program and will consist of: 

1. 1.5-mile run under 13:07 for the minimum passing score of 70 - scores will then be prorated with 

8:30 considered to be 100. 

2. Sit-ups (1 minute) - The minimum number is 25 for a grade of 70 - with one-half a point awarded 

for each additional sit-up. 

3. Push-ups (1 minute) - The minimum number is 25 for a grade of 70 - with one-half a point awarded 

for each additional push-up. 

4. Pull-ups (1 minute) - The minimum number is 1 for a grade of 70 - with one-half a point awarded 

for each additional pull-up. 

PAT #2 will be given approximately two months after PAT #1: (1 month for Fast Track) 

1. 1.5-mile run under 12:15 for the minimum passing score of 70 - scores will then be prorated with 

8:30 considered to be 100. 

2. Sit-ups (1 minute) - The minimum number is 30 for a grade of 70 - with one-half a point awarded 

for each additional sit-up. 

3. Push-ups (1 minute) - The minimum number is 30 for a grade of 70 - with one-half a point awarded 

for each additional push-up. 

4. Pull-ups (1 minute) - The minimum number is 3 for a grade of 70 - with one-half a point awarded 

for each additional pull-up. 

PAT #3 will be given approximately two months after PAT #2: 

1. 1.5-mile run under 11:30 for the minimum passing score of 70 - scores will then be prorated with 

8:30 considered to be 100. 

2. Sit-ups (1 minute) - The minimum number is 35 for a grade of 70 - with one-half a point awarded 

for each additional sit-up. 

3. Push-ups (1 minute) - The minimum number is 35 for a grade of 70 - with one-half a point awarded 

for each additional push-up. 
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4. Pull-ups (1 minute) - The minimum number is 5 for a grade of 70 - with one-half a point awarded 

for each additional pull-up. 

PAT #4 will be given approximately two months after PAT #3: 

1. 1.5-mile run under 11:30 for the minimum passing score of 70 - scores will then be prorated with 

8:30 considered to be 100. 

2. Sit-ups (1 minute) - The minimum number is 35 for a grade of 70 - with one-half a point awarded 

for each additional sit-up. 

3. Push-ups (1 minute) - The minimum number is 35 for a grade of 70 - with one-half a point awarded 

for each additional push-up. 

4. Pull-ups (1 minute) - The minimum number is 5 for a grade of 70 - with one-half a point awarded 

for each additional pull-up. 

NOTE: All trainees may be subjected to additional PAT tests following PAT #4 during their tenure at 

the academy. 
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Appendix E

Evaluation of a Self-Contained Breathing Apparatus 

for Potential Contribution to a Fatal Event 

in the Fire Service

NIOSH Task Number 20842

NOTE: The full report, including Appendices I–III, is available at 

https://www.cdc.gov/niosh/npptl/ppe-fireservice/completedrpts.html. 

Background

As part of the National Institute for Occupational Safety and Health (NIOSH) Fire Fighter Fatality 

Investigation and Prevention Program (FFFIPP), the National Personal Protective Technology 

Laboratory (NPPTL) agreed to examine and evaluate a self-contained breathing apparatus (SCBA) 

unit. 

This SCBA status investigation was assigned NIOSH Task Number 20842. The NIOSH Division of 

Safety Research (NIOSH/DSR) and the Fire Department were advised that NIOSH/NPPTL would 

provide a written report of the inspections and any applicable test results. 

The SCBA unit was shipped to the NIOSH/NPPTL facility in Morgantown, West Virginia. The unit 

was received on May 13, 2016, and placed in secured storage. 

SCBA Inspection

The unit was inspected on May 13, 2016 by staff from the Morgantown Testing Team (MTT), NPPTL 

(Mr. Jeremy Gouzd, Fellow, and Ms. Karis Kline, Contractor). The SCBA was identified as the Fire 

Department SCBA and was extensively examined, component by component, in the condition received 

to determine how well the unit conformed to the NIOSH-approved configuration. The unit was 

identified as the Scott® Safety Company model Air-Pak® 4.5, 30 minute, 4500 psi unit, NIOSH 

approval number TC-13F-212CBRN. The visual inspection process was documented photographically. 

The cylinder was included and gauges showed that the tank was empty. No facepiece was included 

with the unit. The following components were included with the SCBA unit and were thoroughly 

inspected: mask mounted regulator (MMR) with Heads Up Display (HUD), low pressure line, pressure 

reducer assembly, high pressure line and cylinder attachment, console assembly PASS (personal alert 

safety system), PASS control module, backframe assembly, straps and buckles, cylinder and valve 

assembly. The NFPA approval label was present and readable. The SCBA unit exhibited signs of 

normal wear and tear and did not show any signs of heat damage. All components were in fair to good 

condition. Following inspection, the unit was returned to secured storage until testing was performed. 
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The complete SCBA inspection is summarized in Appendix I of the full report. The condition of each 

major component of the SCBA that was photographed with a digital camera is contained in Appendix 

III of the full report.

SCBA Testing

Testing of the SCBA unit began on August 5, 2016. The purpose of the testing was to determine how 

well the SCBA conformed to the approval performance requirements of Title 42, Code of Federal 

Regulations, Part 84 (42 CFR 84). Further testing was conducted to provide an indication of the 

SCBA’s conformance to the National Fire Protection Association (NFPA) Airflow Performance 

requirements of NFPA 1981, Standard on Open-Circuit Self-Contained Breathing Apparatus for the 

Fire Service, 1997 Edition. 

NIOSH SCBA Certification Tests (in accordance with the performance requirements of 42 CFR 84): 

1. Positive Pressure Test [§ 84.70(a)(2)(ii)] 

2. Rated Service Time Test (duration) [§ 84.95] 

3. Static Pressure Test [§ 84.91(d)] 

4. Gas Flow Test [§ 84.93] 

5. Exhalation Resistance Test [§ 84.91(c)] 

6. Remaining Service Life Indicator Test (low-air alarm) [§ 84.83(f)] 

NFPA Tests (in accordance with NFPA 1981, 1997 Edition): 

7. Airflow Performance Test [Chapter 5, 5-1.1] 

A stock Scott® facepiece was used for testing as no facepiece was provided. The SCBA unit passed all 

NIOSH SCBA certification tests. The measured service time (adjusted to correspond with the recorded 

breathing cycles) was more than the rated service time of 45 minutes. The SCBA unit passed the 

NFPA airflow performance test. The PASS unit, HUD, and alarm systems were all functional. The 

SCBA unit was returned to storage pending return to the Fire Department. 

Appendix II of the full report (online) contains the complete NIOSH test report for the SCBA. Tables 

ONE and TWO summarize the NIOSH and NFPA test results. 

Summary and Conclusions

As part of the NIOSH FFFIPP, the NPPTL evaluated an SCBA unit submitted by the Fire Department. 

The SCBA unit was received at NPPTL on May 13, 2016 and inspected the same day. The unit was 

identified as a Scott® Safety model Air-Pak® 4.5, 4500 psi, 30-minute, SCBA (NIOSH approval 

number, TC-13F-212CBRN). A cylinder was included, and gauges showed the tank was empty. A 

facepiece was not provided with the unit. Inspection of the SCBA components showed normal signs of 

wear and tear, no signs of heat damage, and the overall condition of the SCBA was good. A stock 

Scott® facepiece was used for the testing portion of the evaluation, which began on August 5, 2016. 
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Results from testing showed that the SCBA unit passed all of the NIOSH SCBA certification tests as 

well as the NFPA airflow performance test. If the unit is to be placed back in service, the SCBA must 

be repaired, tested, cleaned, and any damaged components replaced and inspected by a qualified 

service technician, including such testing and other maintenance activities as prescribed by the 

schedule from the SCBA manufacturer. 
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Appendix F

Autopsy Findings

Cause of Death: 

Hyperthermia and Dehydration (based on autopsy, history, and circumstances of death)

Autopsy findings: 

a. Vitreous humor post-mortem chemistry results “consistent with dehydration”

 Sodium 151 milliequivalents per liter

 Vitreous urea nitrogen (VUN) 20 mg/dL 

Normal range: sodium 135–150 mEq/L; VUN 8–20 mg/dL [NMS Labs 2018] 

b. Other vitreous humor results: creatinine 0.6 mg/dL, chloride 113 mEq/L, potassium 

11.9 mEq/L, glucose 11 mg/dL, and no ketones (all within normal ranges [NMS Lab 2018]) 

c. Cardiomegaly (heart weight 450 grams) 

d. Left ventricular hypertrophy (wall thickness 1.7 centimeters) 

e. Microscopic exam of heart: 

 Myocyte hypertrophy; only minimal interstitial and perivascular fibrosis

 Multifocal contraction band necrosis 

f. Coronary artery atherosclerosis 

 40% to 50% stenosis of left main artery 

 10% to 20% stenosis of left anterior descending artery

g. No evidence of infection, sepsis, or rhabdomyolysis detected on microscopic exam 

h. Bladder contained 35 milliliters (cc) of clear, yellow urine 

i. No evidence of pulmonary embolus (blood clot in the lung arteries) 

j. Carboxyhemoglobin level < 5% (not elevated)

k. Normal hemoglobin and thyroid studies 

l. Toxicology testing was negative. 

Medical co-author’s discussion:

The predicted heart weight for males of the same body weight as the Cadet is 331 grams (251–437 

grams), according to autopsy studies by Kitzman et al. [1988]. The normal thickness of the wall of the

left ventricle is in the range of 1.07 to 1.39 centimeters (average 1.23 centimeters) [Kitzman et al. 

1988]. The findings of a heavier than predicted heart, thicker than normal left ventricle wall, and 

enlarged ventricles may be consistent with physiologic “remodeling” that can develop in response to 

intense and prolonged endurance training [Weiner and Baggish 2012]. These changes are often 

referred to as “athlete’s heart.” 
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It is not uncommon to find coronary atherosclerosis at the time of autopsy in adults whose deaths were 

not due to heart disease. (Nearly 1 in 4 military members in their 30s who died from combat or injuries 

were found to have some degree of atherosclerosis at autopsy [Webber et al. 2012]). Stable coronary 

atherosclerosis lesions that cause < 50% obstruction in an artery are very unlikely to be of clinical 

consequence [Knudtson 2014]. 

Regarding hyperthermia/heat stress, autopsy findings from these deaths may be absent or nonspecific, 

particularly for victims who succumb shortly after severe hyperthermia develops [Lifschultz and 

Donoghue 1998; Nixdorf-Miller et al. 2006]. In heat stroke victims who survive for hours, postmortem findings are not consistent but may include evidence of rhabdomyolysis, acute kidney damage, 

liver failure, and other pathological changes. 

REFERENCES

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, PMID: 

3276974. 

Knudtson M [2014]. Coronary scoring systems: a historical perspective, March 2014. Alberta, Canada: 

Alberta provincial project for outcomes assessment in coronary heart disease (APPROACH) 

https://www.approach.org/pdfs/tutorials/History_of_Coronary_Scoring_March2014.pdf.

Lifschultz BD, Donoghue ER [1998]. Forensic pathology of heat-and cold-related injuries. Clin Lab 

Med 18(1):77–90, PMID: 9523065. 

Nixdorf-Miller A, Hunsaker DM, Hunsaker JC 3rd [2006]. Hypothermia and hyperthermia 

medicolegal investigation of morbidity and mortality from exposure to environmental temperature 

extremes. Arch Pathol Lab Med 130(9):1297–1304, PMID: 16948514. 

NMS Labs [2018]. Test catalog. Willow Grove, PA: NMS Labs, http://www.nmslabs.com/test-catalog. 

Webber BJ, Seguin PG, Burnett DG, Clark LL, Otto JL [2012]. Prevalence of and risk factors for 

autopsy-determined atherosclerosis among US service members, 2001-2011. JAMA 308(24):2577–

2583, http://dx.doi.org/doi:10.1001/jama.2012.70830. 

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.