“A new inferno,” an August 2026 New York Times documentary, follows Phoenix Fire Department Engine 18 as they responded to reports of people overheating in the scorching heat of downtown Phoenix during the summer of 2025. The National Weather Service Phoenix reported on Instagram that the average temperature of 96.2 degrees Fahrenheit was the fourth hottest meteorological summer (June, July, August) on record. In July 2025, the average minimum temperature was 86.2 degrees Fahrenheit and average maximum temperature was 107.6 degrees Fahrenheit.
In that environment, with shade hard to come by, there are few safe places outdoors for anyone.
READ NEXT | Managing hyperthermia: Prevent heat exhaustion, heat stroke in fire/EMS
“It’s the evolution of our job. Heat related emergencies are definitely on the rise and we are on the frontlines,” a Station 18 firefighter said in the documentary. “This is what we have to do.”
Extreme heat isn’t unique to Phoenix. July 2026 was the warmest month on record in the lower 48 United States, according to the National Centers for Environmental Information, which also forecasted above-normal temperatures in August.Record-breaking heat, it seems, is becoming the new normal, as average summer temperatures set or near historical records and the hot season starts earlier and ends later. With that in mind, here is how to use the “A new inferno” documentary and the ice immersion cooling it teaches in upcoming EMS and fire training.
Watch “A New Inferno”
After setting the scene of America’s hottest city, the video demonstrates how Phoenix firefighters and hospital staff call a hyperthermia alert and practice ice bag immersion. The tools are simple — a rubber bag, ice and water, but the timing and choreography are lifesaving.
In addition, the filmmakers and firefighters capture the complexity of working in extreme heat you don’t get by simply reviewing heat stroke signs and symptoms. When a crew responds to an unresponsive man on the street, they quickly assess his heat stroke and move him into the immersion bag, only to discover the ice bags they carry on the engine have already melted. They pour cold water on the man, who’s tympanic temperature is 107 degrees Fahrenheit, while waiting for ice to be delivered by the ambulance.
At the end of the documentary, two firefighters climb to the roof of Station 18. As they watch the sunset and decompress, they wonder aloud about the patients they care for and if they are doing enough.
“I felt like we did the best we could for him,” one of the firefighters said. “If it’s so hot out here we got to throw people in bags, what are we doing out here?”
Identify heat-vulnerable patients in your community
Because hyperthermia is historically associated with exertion on the football practice field or outdoor job sites, it is important to discuss that heat stroke has non-exertional causes and is an increasing threat to people who are underhoused or unhoused, those who abuse drugs and alcohol, and those with chronic medical conditions. Aging and medications can disrupt thermoregulation for elderly patients. Those same patients, because of a fixed income, may not be able to cool their home or apartment to a comfortable temperature, or self-evacuate to a community cooling center during extreme temps.
Distinguish heat exhaustion from heat stroke
Heat exhaustion is a circulatory system problem caused by heat-related fluid loss (perspiration) and inadequate fluid intake. The patient’s history often includes exertion, excessive sweating and fluid intake that can’t keep up with the fluid loss. Like other types of volume shock, the patient presents with tachycardia and tachypnea. Hypotension may be a late finding of heat exhaustion and the patient’s core temperature is less than 40.5 degrees Celsius.
Heat stroke is a brain overheating problem that is characterized by severe hyperthermia, typically a core temperature above 40 degrees Celsius, plus brain dysfunction with signs and symptoms like confusion, combativeness, delirium and seizures. The patient’s skin condition and moisture are not a determining finding for heat stroke. Depending on their circulatory volume and perspiration, their skin can be hot and dry or hot and moist. Instead, focus your assessment on the scene size-up — heat exposure, core temperature and level of consciousness.
Measure core temperature accurately
In the field, a rectal temperature probe is the closest measure of a core temperature. If a rectal temperature isn’t available, combine clinical assessment of the environment with the patient’s warmth and reduced level of consciousness to diagnose heat stroke. Oral, axillary and tympanic temperature measurements can underestimate the patient’s core temperature, making them unreliable for diagnosing heat stroke.
Recognize complicating conditions
Heed the reminder of Phoenix and assess for comorbidities like alcohol or drug intoxication, chronic illness and superficial or partial thickness burns. Some of these, like fentanyl overdose, may have caused the patient’s dangerous heat exposure and heat stroke, while others like burns, might be a result of becoming unresponsive on the hot pavement.
Start rapid whole-body cooling immediately
Heat stroke is a life-threatening emergency and deserves the same all-hands and choreographed care given to sudden cardiac arrest and multi-system trauma patients. Lifesaving care for heat stroke is rapid, immediate immersion in cold water.
When the Phoenix Fire Department adopted the practice in 2024, Dr. Aneesh Narang, assistant medical director of emergency medicine at Banner University Medical Center in Phoenix told the Associated Press, “The standard of care, which starts on scene, is cold-water immersion.”
During the hands-on training session, remind personnel that we lose heat through radiation, convection, evaporation and conduction. Heat loss is most efficient from conduction. Ice water is more efficient at conductive heat loss because it maximizes the total body surface participating in conduction. The body’s thermoregulatory system is already pushing heat away from the core to every capillary bed to lose heat.
The goal of treatment is rapid cooling that starts in the field. The National Association of EMS Physicians, in a 2018 consensus paper, advises EMS to “cool first, transport second” and recommends that cooling techniques should result in a reduction of the patient’s rectal temperature to less than 38.6 degrees Celsius (101.5 degrees Fahrenheit) within 30 minutes.
Practice cold-water immersion as a crew
In a 2024 update to the Wilderness Medical Society Practice Guidelines for the Treatment and Prevention of Heat-Related Illness, cold-water immersion was described as “the gold standard for achieving rapid temperature reduction.”
Hands-on training, following the example of the Phoenix Fire Cadets, is the centerpiece of your training session. Lift a manikin or willing human subject into a rubber bag, pour ice over the chest and groin, add water and close the bag. Move the bagged patient to the cot and ambulance as the crew continues to assess airway, breathing and circulation, and provide other supportive treatments, like airway adjuncts and IV access.
Stock the equipment before the heat call
Here’s what you need for rapid, immediate field cooling:
- A person-sized rubber or plastic bag. A tarp can be used, but ice and water will probably leak out of the tarp.
- Ice. Lots of ice. When Engine 18 discovered their ice melted, they asked the ambulance to bring four 5-pound bags of ice.
- A gallon or more of water. Pour the water over the ice and patient, but not into the patient’s airway, as they may not be able to swallow.
Use TACO when immersion is impractical
These two videos demonstrate and explain tarp-assisted cooling with oscillation (TACO).In the Eastern Kentucky University video, Dr. Eric Fuchs states, TACO “is nearly equivalent to cold-water immersion when done correctly.”
- Heat stroke treatment in the field, Eastern Kentucky University
- TACO Method Provides Rapid Cooling (Christopher Sampson, MD), MU Health
Regardless of the technique, rubber bag or TACO, leave the patient’s face exposed for airway monitoring and management. Don’t delay immersion to insert a just-in-case airway adjunct or start an IV. Cold IV fluids might help if the patient is also fluid depleted, but the trickle of coolness isn’t nearly enough to counter the extreme core temperature.
Know when to stop cooling
Continue cooling the patient until their rectal temperature is below 38.6 degrees Celsius (101.5 degrees Fahrenheit). The patient’s extreme core temperature is lethal, unless it is rapidly lowered.
Time is brain: Make heat stroke a high-acuity training priority
Heat stroke is cooking the patient’s brain. Like stroke and other time dependent emergencies, field treatment is focused on recognizing and reversing the life threat and transporting the patient to definitive care.
