May 24, 2018

Firefighters absorb chemical products through their protective gear

Firefighters absorb chemical products through their protective gear

It is acknowledged that cancer incidence rates are higher among firefighters than the general population despite their higher level of fitness.

Fire combat is still one of the most dangerous occupations, and one of the least studied in terms of exposure and the connection with occupational diseases. The cancer incidence seems to be higher in firefighters compared to the general population. In most Canadian provinces, the presumptive legislation recognizes come cancer as occupational related diseases for firefighters despite the lack of studies to better understand all the cause and effect relationships. Since many cancers have an environmental component, the occupational exposure of firefighters to carbon combustion by-products, such as polycyclic aromatic hydrocarbons (PAH), is a cause for concern. The skin of firefighters may be vulnerable to chemical products due to the permeation/penetration of combustion by-products through the personal protective equipment (PPE) or caused by a cross-contamination from the PPE to the skin.

While it’s apparent that the respiratory organs of fire service workers are most at risk because of the many toxic combustion products released during a fire, skin contamination protection has been much less extensively studied.

Small combustion particles (≤ 1 μm) and semi-volatile compounds can go through many layers of the firefighter’s protective clothing by permeation and penetration through interstices and other imperfections. For firefighter clothing, two types of infiltrations are relevant as there is a usual lack of resistance or absorption capacity to limit the transfer of airborne chemical products. Furthermore, frequent air movements due to the fabric’s air permeability and the absence of joints combined with intensive body movements during exercises allow harmful particles to end up on the surface of the skin despite the protective clothing.

Increasing evidence shows that firefighters are at a greater risk of cancer and other severe illnesses compared to the population in general, in part because of their exposure to dangerous chemical components found in smoke. The University of Ottawa has recently conducted a study indicating, among other things, that the Ottawa firefighters have three to five times more toxic chemicals in their urine after a fire than during one. And more significantly, the study suggests that the chemicals made their way inside the body through the skin.

The study is not the only one coming to this conclusion. Several more recent studies indicate that skin absorption of airborne chemicals could play a much greater role than what we previously thought. The harmful substances in question would primarily be polycyclic aromatic hydrocarbons (PAH), substances classified as having the highest carcinogenic potential according to the US EPA toxicity rating scale.

Smoke diving simulations established the importance of inhalation and skin absorption through multiple paths. Studies revealed that even a self-contained breathing apparatus (SCBA) worn and fully operational is contaminated within 25 minutes following its use in fire combat situations. The results mean the accumulation of toxic substances on clothing and equipment used repeatedly, leading to an increase in toxic exposure for firefighters through their PPE. The neck is the primary site of skin exposure and the helmet only offers minimal protection. When firefighters remove their equipment, skin and inhalation exposure to contaminants persists.

To minimize the risks associated with toxic particle exposure, it is important to decrease the exposure of firefighters to combustion particles by reducing the amount of time the equipment is worn and material manipulation after smoke exposure.

Reduce exposure to PAH for firefighters:

The first step is to implement a decontamination process. For example, before taking off the respirator, the worker must remove his bunker gear, including the clothing worn under the fire-retardant protection as well as the other contaminated layers in contact with the skin. The material used during fire combat must be kept in separate compartments of the truck and firefighters must wear clean clothes before returning to the fire station.

As PAH are extremely volatile, it is important to wear all the protective equipment, including the helmet and respirator, even for outside work.

Extra layers of clothing under the flame-resistant protecting may increase the protective factors. However, adding layers of permeable clothing allows an accumulation of contaminants on the fabric. Removing clothing quickly can be beneficial to reduce the risk of prolonged skin exposure.

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