The invisible risk to firefighters
Polycyclic aromatic hydrocarbons (PAH)
In this interview, Dr Jonas Schubert explains why he and his fellow firefighters aren’t completely protected against carcinogens despite wearing protective clothing. Joining forces with other researchers, he developed a paste that allows rescue workers to easily and efficiently remove harmful substances such as polycyclic aromatic hydrocarbons (PAH) from the skin. But the really clever part is that it binds the toxic molecules and can simply be rinsed off with water without damaging the skin barrier.
Firefighters have a significantly increased risk of developing cancer. Why is that?
Firefighters are exposed to toxins they need to protect themselves from during fires, but also during hot fire training or at the respiratory protective equipment workshop.
Let’s take a look at the most frequent problem: Fires produce polycyclic aromatic hydrocarbons, or PAH for short. Unlike soot, these PAH are invisible to the human eye. But precisely these molecules are carcinogenic.
Firefighters wear protective clothing and respiratory protection. So where’s the problem?
That’s true, but they don’t offer total protection. Respiratory protection ensures that we don’t breathe in the PAH. But we humans absorb PAH through the skin. Or through hand-to-mouth contact.
The protective clothing isn’t particle-tight, so during fires or in fire containers, PAH are deposited onto the skin at the interfaces to the protective clothing especially.
And after responses, all the way to the respiratory protective equipment workshop, the handling of contaminated materials is crucial. This is where, in the aftermath, PAH are often transferred to the skin, or they’re transported to the fire station, contaminating door handles, areas where we eat, etc.
How often do carcinogens have to penetrate the skin before they actually become a danger to the human organism?
In occupational health and safety, there is a threshold for most harmful substances – all the way down to dust at construction sites. As long as our body isn’t exposed to more than this limit, statistically speaking, the risk of resulting health issues is low enough for us in occupational health and safety to accept these measures taken, without having to take any further steps.
But there isn’t a biological threshold for PAH! Even the smallest amounts can make all the difference. Statistically, it isn’t possible to say that a certain amount above 0 is okay. The logical consequence would be to completely rule out any and all skin contact with PAH. In practice, however, that simply isn’t possible. So we have to ask ourselves what we can do to reduce the absorption of PAH as far as possible.
And how can PAH be washed off the skin?
An interesting question, as there have been new insights into this in recent years: For years, we fire brigades have relied on soap or decontamination wipes. This may get rid of the soot, but in reality more than half of the PAH remain on the skin – that figure jumps to more than three-quarters with the wipes. And these are substances that are carcinogenic and that are absorbed through the skin.
So we need a different washing method to remove these PAH molecules from the skin. With pak-ex, we have developed a paste that contains no scrubbing agents or soaps at all, but still performs unbelievably well in terms of decontamination, achieved with clays that bind the PAH.
The second important effect is that our patent doesn’t damage the skin barrier during washing. This is one of the problems with soaps, wipes or cleaning pastes, which have a negative effect on the skin barrier, enabling toxins to enter the body faster and more easily. So there are two reasons that they’re not at all suitable after a fire, after an exercise in a fire container or in the respiratory protective equipment workshop.
How soon should the skin be cleansed of toxic substances after a call-out?
The faster, the better, ideally still while at the scene. If possible, showering at the scene, as like I’ve said all the interfaces to the protective clothing – that is, the interfaces between boots and trousers in the leg area and in the hip area between the jacket and trousers – are potential points of contact.
If it isn’t possible to shower on site, which is currently still the case for most fire brigades, we recommend at least preliminary cleaning at the hygiene board, that is, cleaning the hands, face, throat and neck. And then promptly taking a shower at the fire station.
In the MEIKO online magazine, rescue workers will find more tips for protecting themselves and their colleagues from toxic substances, for example in the articles on operational hygiene. In the most recent one, Dr Jonas Schubert also explains when it makes sense to wash your hands with soap and when with soap-free products. What personal protective equipment SCBA technicians should wear when working in dirty and clean areas is discussed in the article: Treatment of respiratory protective equipment.
