Staying Cool in the Hot Zone: Preventing Heat Incidents with Cooling in the CBRNE/HAZMAT Environment


I worked in the Chemical, Biological, Radiological, and Nuclear (CBRNE) Defense world for three years within the Army. I’ve worked the last three years as a full-time HAZMAT Urban Search and Rescue Technician/Medic. Throughout these roles, I have spent well over 100 hours in a HAZMAT suit and hundreds more treating and monitoring soldiers for heat related injuries. Overheating is the most common injury associated with wearing one of these tarp-like protection suits. 

Rescue Team about to entry the Hotzone in 103 degree (F) weatherRescue Team about to enter the Hot Zone in 103 degree (F) weather.

Help, I've Fallen and I Can't Get Up!

Let’s walk through a common HAZMAT work scenario to give you a picture of these extreme conditions:

As you work beside your HAZMAT teammates, you start to feel the sweat drip down your shoulders, the gloves of your suit sloshing with accumulated sweat. How can I be this sweaty? You think to yourself. The sad reality is that your team has only been working for twenty or so minutes. You stand to lift a tool up to your team lead who is clambering into a wrecked vehicle. As you lift the 45 pound splitters, you see white and collapse to the ground!

This brief account sounds extreme but is a common scenario in the CBRNE/HAZMAT field. The irony is that the suits worn by the HAZMAT workers to protect them from the dangerous environment can actually cause an extreme and potentially dangerous heat environment within the suit itself.

Wet Bulbs and Heat Index

Cooling is crucial when wearing protective suits in the CBRNE world.  In 2016, according to The Medical Surveillance Monthly Report (MSMR) over 401 Soldiers suffered from Heat Stroke and 2,135 suffered from heat exhaustion in the Active Duty component alone! The number of annual heat related injuries within the Active Army continue to rise with each year. To have a more holistic understanding of the dynamics at play, let’s discuss the Wet Bulb Globe Temperature (WBGT) and how the U.S. Army uses this information to create guidelines on recommended work/rest cycles.

The Wet Bulb is a small device that uses temperature, humidity, wind, and a slew of other things to determine the WBGT. Once the WBGT is determined, this data point can be located on the chart. From there, individuals and organizations can find recommendations on their working protocol and determine the safest work rotations for their employees. For example, according to this chart, wearing the MOPP 4 (CBRNE Suit) adds 20 degrees to the external temperature. This increase may not be problematic in balmy 75 degree F weather, but when it is 98 degrees F out with 95% humidity, that 10-20 degrees changes the temperature conditions and safety requirements dramatically!

The Risk to Workers

Naturally, our bodies have several ways to cool down. Because of the protective nature of CBRNE Suits, the suit itself cuts off the flow of air between your body and the external environment. As a result, your body’s ability to cool down is severely limited. These circumstances can lead to very serious heat injuries. Some units try to mitigate the heat by using semi-permeable suits such as the Blauer suit (From personal experience, a HAZMAT suit is hot!  No matter what!).

The risk of heat injuries is so great within the suits that workers are required to have their vital signs checked before and after their work cycles. It is not uncommon for an individual to get out of the suit and have a body temperature of 100-103 degrees F and to lose 3-5 pounds over the course of their shift! These changes do not always warrant an emergency - the human body is generally able to compensate for these extreme conditions while in the suit and then return to normal during the rest cycles. During extended work periods, though, the body’s ability to maintain homeostasis slowly declines. At that point, the worker is highly susceptible to heat exhaustion.

The IcePlate: A Cooling (and Warming) Solution

Rescuer about to go in a confined space, the IcePlate fits comfortably underneath that harness.

Presently the cooling options made available by the Army to a Soldier working in a contaminated area are severely limited. Insulated CamelBaks may be worn outside of the suit, however these are bulky and cumbersome and are often left behind by Soldiers who prefer to not have something outside of their suit to catch on things. Once the Soldier is off shift and through decontamination, ice sheets, oral and IV fluids, and cold packs are the options to cool down. Oral fluids are the best medical method of re-hydrating an individual, followed by IV fluids, which are expensive and often saved for life threatening emergencies (this also applies to the ice sheets).

The other important factor in reducing heat injuries is the Work/Rest cycles.  These cycles are important but also extremely frustrating. When you are on a 30 min work/30 min rest cycle and it takes 15 minutes just to get from the “Cold Zone” (ie. non-contaminated area) to where you are working, you barely start your work before it’s time to break again.

In my endless search to find a better solution, I came across the Qore Performance IcePlate.  When I started to wear the IcePlate under my suit, the change was dramatic. I can’t begin to tell you how different I felt working in the hot zone in my CBRNE Suit with an IcePlate strapped to my back.  The IcePlate is literally a block of ice. As the water melts, the user can drink the water (There are adapters to the Gas Mask that allow the IcePlate to be worn externally and hooked to the mask in order to drink, if necessary). IcePlate cools the body conductively, while providing the hydration needed to keep up with my work demands (i.e. climbing dozens of stairs while carrying hundreds of pounds of equipment). While wearing the IcePlate, I feel energized and more alert on the scene. I found that work cycles could increase to 40/20 or even, 50/10. This is huge from a productivity standpoint. In addition to the increased work capability, the IcePlate can also be decontaminated for a majority of the hazardous chemicals that we work with. (IcePlate can also be filled with warm water in cold conditions, providing conductive heating - see picture below)

Rescue medics about to enter hot zone. Temp mid 40's, I used the Ice plate as a heater in this pic. 

I came across the Qore Performance IcePlate two years into my current three year HAZMAT mission and wish I had found it sooner! The IcePlate offers a great middleman solution to HAZMAT and CBRNE workers. It’s sleek, affordable, easy to wear and tacticool. Most Soldiers are willing to wear it simply because it looks cool, keeps them cool, and stays out of their way! A great device that I hope to see become a commodity among both the military and civilian CBRNE/HAZMAT workforce!

-Jeff Johnson

Instagram: @rescue13
Facebook: @R3scue13
Jeff Johnson is a 26 year old Utah native who enlisted into the Army Reserves right out of high school. He has filled multiple rolls within the last 8 years in the service including Combat Medic, Licensed Practical Nurse, Instructor, Training Non-Commissioned Officer, and presently fills the roll as a Rescue-Medic within the Chemical Response Enterprise Task force. 
When not working for the Army, Jeff can be found chasing his punk dog away from the garbage cans, camping, hiking, rock climbing, and spending time with friends and family. He also enjoys long walks on the beach with his fiance.
 

Myself (on right) and my team mate in Times Square, New York City working with FDNY on a nerve agent scenario.

Sources:

http://blog.mesonet.org/agriculture/wet-bulb-globe-temperature-what-it-is-and-how-to-use-it/

https://health.mil/News/Articles/2017/07/20/Exertional-Heat-Injuries-Pose-Annual-Threat-to-US-Service-Members

https://www.armystudyguide.com/content/powerpoint/First_Aid_Presentations/heat-injuries-2.shtml

https://health.mil/News/Gallery/Infographics/2017/07/20/Preventable-and-Treatable-Know-the-Signs-of-Heat-Exhaustion


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