Skin's role in firefighter rehab
Fire scene conditions conspire to circumvent the skin's ability to keep deadly toxins at bay
By Bruce Evans
Many would miss this on a trivia quiz, but the skin is the human body's largest organ. And the importance for firefighters to protect their skin also goes largely unrecognized.
With a huge surface area and critical biological functions, the skin is key to providing a barrier to toxins and regulating temperature.
For the latter, the skin changes dramatically to provide thermoregulation and ensure proper cooling. It needs to function correctly for you to know when the heat is too much.
Yet the care and consideration of the skin is not addressed in the NFPA 1584 Standard on the Rehabilitation Process for Members During Emergency Operations and Training Exercises for Firefighter Rehabilitation. NFPA 1581 Standard on Fire Department Infection Control Program does address hand washing and decontamination as it relates to blood-borne pathogens.
This, of course leads to skin's function as barrier protection.
Until recently the focus has always been about breaks in the skins and not the inherent nature of how toxic material crosses that barrier. Both the introduction of blood into a wound and the absorption of toxic byproducts of combustion have the same consequences that can add to the potential for death, cancers or disease.
Whether it is the risk of liver cancer via an exposure to Hepatitis C or the risk of myeloid leukemia from the breakdown of formaldehyde in pressboard and glues for laminates, these exposure may be extracting a price much later in our careers.
Toxins' direct route
The skin is very porous and extremely vascular with a lot of small blood vessel, sweat glands and pours that can all act a potential pathways for toxins to enter the body. As toxins sit on the skins they readily migrate to the hands or eyes, making it easy for substances to be ingested or pass through the even more vascular eye.
More significant is how these chemicals embed in the pores that open to help thermo-regulate heat stress during firefighting operations. With every 5 degrees that body temperature rises, skin absorption rates increase by as much 400 percent.
The other major component of the skin is the lipids or a thin layer of fat that makes the skin elastic. The skin is made up of a lipid bi-layer that helps protect the body from a variety of substances getting into the body.
The sweat glands and subcutaneous tissues have a lot of lipid or fatty structures. Many toxins are lipid soluble meaning that they pass though the layers or they lodge in the lipid layer.
The unfortunate part of toxicology is that lipid-loving toxins stick or migrate to fat tissues. The commonly used flame retardants known as polybrominated biphenyls has an affinity to lodge in lipid layers or fats. When it comes to skin exposure, these four terms should be part of a firefighter’s vocabulary: furans, dioxins, benzene and radical aldehydes.
The big four
In a 2014 article published in the Annals of Occupations Hygiene entitled "Systemic Exposure to PAHs and Benzene in Firefighters Suppressing Controlled Structure Fires," researchers from the Illinois Fire Service Institute and NIOSH found that polycyclic aromatic hydrocarbons (PAHs) and other aromatic hydrocarbons were present in firefighters after fire suppression and overhaul activities in fire simulations.
The PAHs most likely entered firefighters' bodies through their skin, with the neck being the primary site of exposure and absorption due to the lower level of protection from hoods. Aromatic hydrocarbons could have been absorbed through the skin during firefighting or inhaled while doffing gear that was off-gassing contaminants after the fire simulations, according to the study.
The hood serves as a big sponge full of the toxins sitting around the neck. The skin thickness of the neck along with the blood and lymph vessels in the neck make it a super highway for skin absorbed toxins and carcinogens.
Brominated flame retardants are used to slow the rate of burning in plastics, foams, fabric and other materials. These flame retardants convert into dioxins and furans when burned.
Materials treated with brominated flame retardants also create more carbon monoxide and smoke, while providing a very little increase in fire resistance. A concerted effort to remove these chemicals has been met with strong resistance from the chemical industry and legislative gridlock.
Radical aldehyde causes inflammation and exhibit high reactivity with bio-molecules, such as proteins, DNA and the lipids that make up the base layers of the skins. The higher concentrations correspond to pathological situations.
According to the study, adehydes can lead to oxidative stress, a state with increased formation of reactive oxygen species that overwhelms antioxidant protection and inflicts DNA damage, lipid peroxidation and modifies proteins. Acrolein is one of these aldehydes. The malfunctions can promote numerous diseases, involving cancer, cardiovascular disease, diabetes, atherosclerosis, neurological disorders and chronic inflammation.
Sweat it out
To combat this, keep towels or disposal fire wipes available to remove soot and unseen particulates or toxins from the skin in the rehab sector. After the incident, it is critical that firefighters shower and clean their turnout gear.
Canadian firefighters have been using saunas and bicycles to detoxify after a fire. The University of Alberta has identified that sweating is the best way to remove heavy metals and other toxins from the body.
The "sweat study" compared measurable amounts of toxins, including heavy metals, and found them more pronounced in sweat than in blood. Urine measurements are similar to those that come from sweat measurements.
The study also found sweat more reliable than blood for detecting cadmium antimony and tin from the test subject that did not show up in their blood or serum. Testimony by Canadian firefighters about how quickly the off gas and smell of a fire is removed is also an indicator of the detoxification potential of steam and sweat.
At the very least showering after the fire should be common practice. Firefighters should not be returning to bed or lounging on station furniture without removing as much of the products of combustion as possible.
The final threat to skin comes from above. As firefighters shed gear and expose skin to the sun's ultraviolent rays, they often forget the risk.
Melanoma remains a significant risk to firefighters no only due to sunlight exposure but the skin's exposure to carbon and coal tar, which has for years been linked to skin cancer. Sunscreen is often neglected in fireground rehab, but needs to be a staple.
While easy to ignore, the skin cannot be taken lightly in firefighter rehab.
About the author
Chief Evans is the fire chief and a paramedic at the Upper Pine River Fire Protection District in Bayfield, Colo. He is on the board of directors at the National Association of EMT's, a National Fire Academy instructor and sits on the National Academy of Science's Institute of Medicine's Preparedness Committee. He has a master's degree in public administration and bachelor's degree in science from the University of Nevada, Las Vegas. You can reach him at Bruce.Evans@FireRescue1.com.