“Everything’s fine, until it’s not.” For firefighters, heat-related illness can fulfill this prophecy like few other fireground events. Unlike changing out an air bottle, there’s no quick fix for heat-related illness once crews begin to experience symptoms. Little can be done except to remove afflicted personnel from operations and use relief crews if they are available.
Because of this, firefighter safety in hot weather is a constant concern for fire service leaders — especially during the summer months. Establishing a fireground rotation schedule and recognizing early signs, however, can dramatically reduce rehab time, allowing for preservation of resources.
Heat-related illness comes on swiftly and sometimes without notice. Crews begin to heat up and sweat when they put on their gear and mount the apparatus, and their internal temperatures continue to rise upon initiation of fireground operations. This can be a recipe for disaster, but the potential for injury or even death can be mitigated by proper planning and fire scene management.
What Are Heat-Related Illnesses?
According to Johns Hopkins, there are three main types of heat-related illness: heat cramps, heat exhaustion and heat stroke. All three occur as the result of “exposure to abnormal or prolonged amounts of heat and humidity without relief or adequate fluid intake.” Here are the illnesses and their symptoms, in increasing order of severity:
- Painful cramping, particularly in the legs
- Moist, flushed skin
- Painful cramping
- Moist, pale skin
- Body temperature over 100.4 degrees F
- Nausea, possible vomiting and diarrhea
- Headache and/or fatigue
- Feeling generally weak, anxious, or faint
- Dry, warm skin
- Abnormally high heart rate
- Body temperature over 104 degrees F
- Nausea, possible vomiting and diarrhea
- Headache and/or fatigue
- Decreased appetite
- Feeling confused or agitated
- Feeling of lethargy or stupor
- Possible seizures, coma, and death
What Conditions Cause Heat-Related Illnesses?
The Occupational Safety and Health Administration (OSHA) notes that millions of workers are exposed every year in the U.S. to high-heat environments — both indoor and outdoor. While OSHA doesn’t specifically call out firefighting, an examination of the major risk factors allows anyone to draw some conclusions:
- Air temperature
- Physical activity
- Heat sources
- Air movement
- Heavy clothing/protective gear
- Individual/personal risk factors
Obviously, when fighting a fire in the middle of the day during the summer, wearing full protective gear, a firefighter is experiencing most if not all of the risk factors on this list. The most basic element when considering the potential for heat illness, though, is the heat index, which factors in both the air temperature and the dew point or humidity. You can calculate the heat index using this handy online tool. Firefighters and others should take precautions anytime the heat index nears or exceeds 90.
Another factor is acclimatization. People exposed to high heat are especially susceptible to illness if they’re not accustomed to the conditions. Again, according to OSHA: “Most outdoor fatalities, 50% to 70%, occur in the first few days of working in warm or hot environments because the body needs to build a tolerance to the heat gradually over time. The process of building tolerance is called heat acclimatization. Lack of acclimatization represents a major risk factor for fatal outcomes.”
Because of this, firefighter safety in hot weather is an especially grave concern at the beginning of the summer or the onset of a particularly warm spell.
What Personal Factors Impact Heat-Related Illnesses?
In addition to environmental factors, individual members of your crew may be particularly susceptible to heat-related illnesses if they are 55 or older or have any of these other personal risk factors:
- High blood pressure
- Heart disease
- Lower level of physical fitness
- Alcohol consumption and illicit drug use
- Use of medications such as diuretics, heart and blood pressure medications, stimulants, sedatives, tranquilizers, and medications for psychiatric conditions
- Other risk factors including heart, lung, or kidney disease; mental illness; and sickle cell disorder
When it comes to firefighter safety in hot weather, Lexipol’s Heat Illness Prevention Training Policy, Heat Illness Prevention Program Policy and the On-Scene Rehabilitation Procedure can provide the foundation for a safer fireground.
Increased Risks on the Fireground
The impact of firefighting activities on the potential for heat-related illnesses is significant. When determining whether a crew is at risk for heat cramps, heat exhaustion, and/or heat stroke, an incident commander (IC) should consider the following:
Climatic conditions: Again, when the heat index exceeds 90, early onset of heat exhaustion and/or collapse becomes more likely. Rehabilitation efforts should generally be established when ambient air temperature is over 85 degrees and there is a potential for extended operations. If the IC even thinks any of these conditions may exist, rehab resources and additional crews should be requested while the first crews are en route. In the time it takes for rehab units to arrive, locate and establish formal rehab, initial crews may already be suffering from heat-related illness.
Length of the operation: Pay close attention to the severity and anticipated length of the fire incident. As a general guideline, it’s good to observe the two-bottle rule: After the use of two air bottles (or 30 to 60 minutes of strenuous activity), a firefighter should be evaluated in the rehabilitation area. The higher the heat index, the shorter the active times should be. Rehabilitation should generally be considered for second-alarm fires or greater. Prolonged motor vehicle incidents and heavy rescues in hot weather are additional examples where rehab is appropriate.
Amount of exertion: Officers should maintain an awareness of the exertion/exhaustion level of crews. The degree of exertion can vary greatly in each incident. Individuals who are under-hydrated or are on the first day back after any gastrointestinal illness are particularly susceptible to early onset of heat-related illness.
Pre-event shift activities: Dehydration and heat illness can have a cumulative effect on personnel who are constantly working in the heat during a shift. Multiple responses, as well as completing regular station duties, can compound over time to cause heat-related illness. Therefore, the IC and officers should consider the workload of the crew throughout the shift when determining the need for rehab operations on any single incident.
Managing Crews in a High-Risk Incident
Let’s face it, practically everyone looks overheated during a fire or rescue incident. That being the case, how can officers size up their crews and determine who needs relief before operations suffer? When should an incident commander (IC) establish formal rehab? For practical purposes, if you think you need formal rehab, you probably need formal rehab.
When resources permit, assign a rehab officer. The IC should get this responsibility moved off his or her plate as soon as practicable. An assigned rehab officer can focus on those tasks more effectively.
Hydrate, Hydrate, Hydrate: One of the best things crew members can do to prevent or delay the onset of heat-related illness is to remain hydrated. At the station and while performing routine tasks, crews should drink plenty of water and avoid caffeinated and sugary beverages. During hot and/or humid weather, where resources permit, station commanders should consider stocking a case of water or a large cooler on responding apparatus, along with ice, towels, misting fans or other cooling resources. Having these items at the ready allows for informal rehab should the IC determine that formal rehab will not be needed, and provides some measure of rehab until formal rehab is established.
Observe and Communicate: Officers and crews should continually look for and communicate signs and symptoms of heat-related illness down and up the chain of command:
IC <–> Group Officers <–> Division Commanders <–> Apparatus Operators <–> Crew Commanders <–> Crew members
Follow Policy and Regulation: When it comes to firefighter safety in hot weather, Lexipol’s Heat Illness Prevention Training Policy, Heat Illness Prevention Program Policy and On-Scene Rehabilitation Procedure can provide the foundation for a safer fireground. In addition, while this article addresses best practices, some states have heat illness prevention-related laws and regulations, which are cited in Lexipol’s state policies. It’s up to every IC to be familiar with policies and regulations and follow them carefully.
Individual crew members should be encouraged to self-evaluate and communicate the need for rest to a supervisor. Heat-related illness training should emphasize that the fear of appearing weak is no excuse for hesitating to communicate the need for rest. Also, supervisors should remember that if one individual is experiencing heat exhaustion, there may be additional members in need of rehabilitation. Therefore, where practicable, crews should rehab together.
This article was originally published on Jun 8, 2018, and was significantly updated on July 13, 2023.