Baby and firefighter
15 Apr 2018

Healthy - "and cancer free" - firefighters - Part 1: A book about improving the working environment


It has long been established that there is a connection between the firefighting profession and the risk of suffering from serious illness. In 2007, the World Health Organization established the connection between the firefighting profession and various forms of cancer - testicular cancer, prostate cancer and cancer of the lymphatic system.

Stefan Magnusson and David Hultman
Text by Stefan Magnusson and David Hultman. Photos by Johan Eklund, except for page 19, David Hultman and page 25, Claes-Håkan Carlsson.

The result was reached by a work group consisting of 24 researchers from ten different countries (Straifet al. 2007).

Many questions remain unanswered and ambiguity surrounds the issue of how firefighters are affected by their work environment over time. The context is complex, as so many different factors work in combination to affect firefighters’ health.

According to research, the health risks entailed by firefighters’ work situation not only lead to cancer, but other health problems such as fertility disorders, cardiovascular diseases, asthma and allergies (LeMasters et al. 2006).

If we summarise firefighters’ conditions, we can distinguish a number of health factors that are known and well documented.

This article represents Chapters 1 and 2 of the book Healthy Firefighters. You can download the entire book as a PDF at CTIF.org here

The firefighting profession involves both evident and hidden exposure to hazardous substances in various forms.

Firefighters often work in shifts with irregular hours and thereby irregular stress patterns.

Firefighters expose themselves to extremely hard physical strain and thermal stresses for short periods.
Being a firefighter is associated with an identity rather than a profession, which leads to long employment.

This in turn lays the foundation for occupational illness.

Noone can know exactly which substances or combination of sub- stances individual firefighters are exposed to, nor the extent to which this happens. For unknown substances, there are no hygienic threshold values. It is not possible to establish what dose or how long an individual must be exposed to unknown combustible gas particles in order for it to be harmful.

It is therefore difficult to introduce health checks that provide an early warning of imminent illness. Some of the diagnostic methods available today for these types of illness are still not perfected and not entirely reliable. One example is the PSA test for prostate cancer (Cooper et al. 2004).

Attempts to diagnose illness at an early stage may therefore lead to unnecessary medical treatment and anxiety in the individual. The types of cancer concerned here are difficult to anticipate and detect in their preliminary stages. At the same time, the connection between a heightened risk of illness and the firefighting profession has been proven. (LeMasters et al. 2006).

A reasonable conclusion from this must therefore be that it is important to minimize the occasions on which firefighters come into contact with unknown matter and substances. Theoretically, it should be possible to completely protect fire- fighters from exposure to harmful substances.

In practice, how- ever, firefighters attending the scene of an accident/fire are sometimes forced to enter an extremely unhealthy work environment if they are to be able to carry out their work. Such situations not only arise in the event of large, spectacular fires but also smaller and more everyday incidents.

These everyday incidents are so frequent that they likely constitute the major portion of the total exposure to harmful substances. Even if the employer were to use all available means to improve the firefighters’ situation, the work environment could not be completely sterile and free from harmful situations and particles. With common sense and simple tools,however, clear improvements can be achieved for firefighters.

Thus far, there has been a lack of a compilation of effective measures for reducing the quantity of foreign substances in fire- fighters’ work environment. This book contains examples and solid advice on how firefighters and organizations can achieve an improved work environment with very simple means and thereby also better health for the firefighters.

The ”Healthy Firefighters” project and the Skellefteå Model‌‌
Sweden is no exception when it comes to problems facing firefighters across the world. Firefighters’ work environment is a global problem and several types of cancer are classed as an occupational illness for firefighters in Canada, Australia and parts of the USA (Forrest, A.2012).

Strong measures are required in order to quickly and adequately effect changes to the current situation. Back in 2006, Swedish employee and employer organizations came together over the issue in a collaborative project which took the name “Friska brandmän” (Healthy Firefighters).

At a fire station of average size in the northern part of the country, a model was created within the scope of the project with which to address the health risks. This work method came to be known as the Skellefteå Model, after the location of the emergency services where the method was developed.

The Skellefteå Model received the prestigious “Good practice award” from the European Agency for Safety and Health at Work in 2011 and thus became internationally acclaimed and recognised. Together with the European Trade Union Institute (ETUI), the European Federation of Public Service Unions (EPSU) has had the Skellefteå Model in its action programme since 2012. The programme names the model the Skellefteå Model. The Skellefteå Model is also referred to as The Swedish Way in international contexts.

Focus on being exposed to unknown substances
This book looks at the link between the firefighting profession and the risk of suffering from serious illness as a result of being repeatedly subjected to unknown harmful substances. It also discusses proposed measures for handling this.

There are many other examples of occupational illnesses that can affect firefighters. Several studies have investigated how night shifts and disruptions to the circadian rhythm affect the human body. It has been proven that there is a connection between disruptions to the circadian rhythm and metabolic disorders and changes in hormone level.

Circadian rhythm disorders also increase the risk of cardiovascular diseases (David and Mirick 2006). Many fire- fighters regularly work in shifts, with frequent night shifts. The consequence is that normal sleep and circadian rhythm are at risk of disruption, in addition to the added stress of emergency call- outs. Such matters are discussed sparingly in this book, however.

The Skellefteå model has become internationally acclaimed and is also known as The Swedish Way.
Furthermore, repetitive strain injuries, musculoskeletal disorders, exposure to liquid foam, fire-extinguishing powder, inert gases and other chemical extinguishing agents are not discussed here. The same applies to burns, blood infections, fertility disorders and injuries caused by trauma such as falls, explosions, being crushed, landslides and training-related injuries.

The term “firefighters” is used here as a collective term for what in certain cases may also include other members of the emergency services.

At the end of the book is a glossary of terms and expressions used in the text.


CHAPTER 2‌‌‌: Combustion gases

Content of combustion gases
The exact substances and combustion products created in a fire depend on the type and quantity of fuel, the size and nature of the surface, access to oxygen, the temperature and other conditions (Karlsson & Quintiere, 2000).

All the variables make it difficult to know what type and quantity of waste products are formed during a fire. The point of departure, however, is that harmful substances are always produced at the scene of a fire.

As there are so many artificial materials in our surroundings, most fires create combustion products derived from synthetic material. In a pyrolysis test of seven common plastics, over 400 different substances have been identified.

It is likely that additional sub- stances which could not be identified were also created (Bengtsson & Antonsson, 1993). In a normal house fire, for example, there is of course a much greater number of substances.

Common substances found in combustion gases, and which have been established as carcinogenic, include: benzene, dioxin, formaldehyde, polyaromatic hydrocarbons (PAH) and vinyl chloride. Some of these substances are easily absorbed through the skin. Certain substances, such as common components of flame retardants, can numb and dampen cough reflexes. This means even more substances are taken up.

Some substances are produced in the largest quantities when the combustion is incomplete; when the fire is very “sooty” and does not have enough oxygen. Other substances continue to be produced once the flame is out but the fuel is still glowing. This is often the case with the final extinction of a fire (Bengtsson and Antonsson, 1993).

New mixtures and compounds of materials are constantly being developed. In our lives we come across more and more new materials with to some extent unknown properties which can constitute a hazard to health in the long and short term. One example is nano- particles, where the extremely small size means that a substance can have entirely different properties when in nano material to those they possess in their normal form.

Nano particles, which have a small diameter compared to other particles, are able to penetrate the protective barriers of living organisms. The nano particles are easily taken up via the skin and airways, transported into the body via the blood, and spread throughout and accumulated in various organs. Whilst research has shown that certain nano materials are very toxic, it is necessary to conduct further studies which more extensively document the impact of these particles on health over a longer period. (Ostiguy et al. 2006).

Despite continuous research in the area, it is almost impossible to document the long-term effects of substances on people at the same pace as new nano- substances appear on the market. More documentation on the substances’ properties when they are combusted is also required.

In fire exercises with well-known fuels such as wood, chipboard,gas, ethanol, diesel and lighter fluid, products such as PAH (polyaro- matic hydrocarbons), VOC (volatile organic compounds), oxides, isocyanates, dioxins and particles which have a negative impact on the body are formed in different sizes.

At the fireground, firefighters are exposed to more unknown substances from the fire than during training as there are many types of fuel present at the same time. Instructors and firefighters that train a lot can, however, be exposed to harmful substances more often during training. (Svensson and Månsson 2009).‌

Spread of combustion gases
Combustion gases and combustion gas particles are able to spread and contaminate the surrounding environment. An indication of this is how even a small, limited fire in a household causes exten- sive damage to adjacent areas and surfaces.

According to Insurance Sweden (2010), payments to policyholders that have incurred fire damage in Sweden cost around SEK 5 billion every year. This only covers property damage. In addition to this, there are costs for healthcare, rehabilitation, absence from work, etc.

Even small apartment fires cost hundreds of thousands of Swedish Kronor in decontamination and restoration costs. It is thus very costly to clean up rooms after a fire so as to be rid of pollutants and odours. In more complex and extensive fires, in industrial areas for example, there is an even greater spread of harmful substances and toxic particles.

In such situations, it is not uncommon for emergency services to inform and warn the public of instances of toxic smoke. The warning may concern people in areas situated relatively far from the scene of the fire. Despite this, unprotected firefighters often find themselves in a considerably worse environment directly adjacent to the scene of the fire.‌‌


Do you as a firefighter know if the house you are extinguishing contains asbestos or how many glass particles from a cut up car window are in the air at incident site?


The body’s uptake of harmful substances
In this context, there are three primary ways in which airborne harmful substances can make their way into our bodies (Rodricks 1992):
- via inhalation
- via skin absorption
- via the mouth (orally).

Uptake via inhalation
All people must breathe to survive. Normal breathing frequency at rest is 12-20 breaths per minute (approx. 7-14 litres of air). Under extreme stress, firefighters with normal lung capacity can meta- bolise up to 100 litres of air per minute (Malmsten & Rosander 2006).

If the air inhaled contains foreign substances, the body’s metabolism of these substances will increase if the individual is subjected to hard work.

It is not uncommon for firefighters to believe they are protecting their airways via simple solutions which in reality do not provide proper protection. Examples of this are breathing through the nose instead of the mouth in the hope that nose hairs and mucous membranes filter and protect them against harmful substances in the smoke. Another example is the “skip breathing method” based on the theory that a lower frequency of breaths in a poor air environment reduces the intake of harmful substances.

It is also common to breathe into the elbow crease or the collar as a means of protection. Unfortunately, none of these methods is especially effective. These methods can be thought to be irrational, but are a real problem and have logical explanations. This behaviour occurs in situations which are not planned or premeditated. Such situations occur for example when the wind suddenly changes, the fire quickly changes character, or when the firefighters need to change position and circumnavigate the scene of the fire. There is often no immediate access to protection for the airways or any possibility of breaking off the task at hand and moving to a better environment.

A common type of emergency callout and task is “smoke smell investigation”. In order to locate a suspected source of fire, it is common for firefighters to use their sense of smell as a tool. For logical reasons, protective equipment for the airways is used in such situations, and at these times firefighters often find them- selves in spaces where people normally do not enter.

These may be attics, storage, crawlspaces, fan chambers and ventilation spaces. In such spaces, the presence of mould, spores, dust and other harmful airborne particles cannot be ruled out. Firefighters normally give no importance to the situation, but in other contexts these environments would be considered hazardous for people to enter.

Harmful substances in connection with fires are taken up by the body via inhalation, absorption through the skin and orally.

It is important to protect bo th the skin and airways in all situations potentiallyinvolving harmful substances.

Situations which at first glance are not perceived as hazardous can easily be overlooked or mistaken as harmless. Respiratory protection is almost always used when the environment is so unsuitable and unpleasant that the firefighters can establish with their natural senses that the environment is toxic or hazardous. But in situations when the normal defense mechanisms such as smell, taste, tear ducts and coughing reflex do not react in a natural way, it is normal for the firefighters not to use breathing apparatus.

Some of the harmful substances that form during fires can be seen and smelt but others are completely invisible or odourless. An environment without an irritating odour or visible soot is thus not necessarily harmless, despite there being no perceived threat. The reason for wearing respiratory protection is not that combustion gases are always toxic; rather, because it is impossible for firefighters to determine whether or not the air they will inhale is harmful (Bengtsson & Antonsson, 1993).


Are there any present or past contexts and situations that you can relate to in which you have unwillingly been forced to inhale bad air as a result of being unable to protect your airways.

When firefighters touch their own skin with contaminated hands, the surface of the skin comes into contact with combustion gas particles.‌

Uptake via skin absorption
There are many situations in which firefighters’ skin comes into contact with harmful substances. This happens every time the firefighters touch their own skin with contaminated hands or with gloves that have been in contact with fire debris, for example when scratching or urinating. Another example is when the fire- fighters are situated in a smoky environment and an area of skin is exposed. Here, particles from combustion gases come into contact with the surface of the skin.

How much of a substance is absorbed by the body via the skin is determined by the quantity and type of substance, the size of the molecules and the skin condition. The substance penetrates warm and sweaty skin quicker than dry or cool skin (Thors et al. 2013).

Firefighters often have warm and sweaty skin when they are in environments in which there are foreign substances. Moreover, it is not only in physically demanding tasks such as smoke diving, hose routing, venting or other demanding operations that firefighters’ skin is warm and moist. The construction and functional requirements of the turnout gear mean that even simpler tasks constitute a higher temperature.

Many medicines are designed to be absorbed by the skin, e.g., analgesic creams, heart disease medication and nicotine patches. As these medicines contain molecules that pass through the skin barrier, they can be absorbed into the blood stream and thereby take effect. In the same way, undesirable and harmful molecules can make their way into the firefighter’s body when they come into contact with the skin.

Today, knowledge about how firefighters’ protective clothing prevents the surrounding environment from reaching the skin during e.g., indoor firefighting.

Think about how your skin has been subjected to visible soot and how long after a fire you can still smell smoke on your body. Is it a matter of minutes, hours or even days? Can you possibly know what substances remain on your skin?


Uptake via swallowing‌
Not all harmful chemical agents and substances from the scene of a fire can be perceived or detected with our natural senses. This makes the situation even more treacherous and is one of the reasons why firefighters tend to swallow unknown substances (oral uptake). This can happen in different situations:

Gases and particles that have entered via the upper respiratory tract are carried via mucous and saliva into the digestive system and are thereby absorbed into the body.

After or during long operations, sustenance is required.

Food is often consumed at or directly adjacent to the fireground, with no opportunity for the firefighters to change clothing, wash themselves or even put the food in a clean place.

Firefighters that use snuff and carry out work that contaminates their hands are at risk of placing foreign substances in their mouth via their fingers, with the snuff as a carrier.
Eating close to the scene of a fire entails a risk of harm- ful substances entering the body via the mouth.

The correct equipment and a good working method are important for protecting firefighters against harmful substances.‌

The hazardous effects of combustion gases
Several research studies have shown that firefighters run a heightened risk of certain forms of cancer (LeMasters et al. 2006). To en- sure the quality and reliability of studies of illnesses that take a long time to manifest, it is necessary to perform measurements over a long period.

In parallel with these studies, firefighters’ personal protective equipment and work methods have been developed and improved, which has had a positive impact on their work environment.

In recent decades, the presence of new materials and chemi- cal substances in our surroundings has increased drastically. For many new substances, there is insufficient or no documentation about how they affect health in the long term (Ostiguy et al. 2006). Professional culture and local work methods are additional factors which affect how firefighters are subjected to combustion gases and their harmful effects.

Combination effects‌‌
When a person is exposed to a number of different substances at the same time, one of the following occurs:

- The substances have no effect whatsoever on one another.
- The substances are aggregated (additive).
- The substances counteract one another’s effects (antagonism).
- The substances enhance one another’s effects (synergy).

Normally, the more hazardous the substances people are subjected to, the more harmful the effect (Mayer 1977). When firefighters are subjected to combustion gases and particles, they are exposed to several harmful substances at once.

The effects of this are difficult to assess, but there is a risk of synergistic effects. Substances which at a determined quantity affect (or do not affect) the body can have an entirely different impact if the body is subjected to another sub- stance before, after or at the same time (Lidman 2008). There is a risk that the mixture of different substances absorbed by the fire- fighter’s body will become even more harmful than the sum of the various components; there can be a synergistic or “cocktail” effect.

When people are subjected to several harmful substances at once, the mixture can be more hazardous than the sum of its parts. This is known as the cocktail effect.

How harmful substances affect the body
Apart from the effects that harmful substances have on health previously mentioned, these substances can also impact on every- thing from the heart to the immune system, the muscles, the nerves, the internal organs and the body’s system for hormone regulation, including the reproductive organs (Lidman, 2008). Children of firefighters run a three to six times higher risk of


Some substances that fire- fighters can be exposed to are suspected to be, or have been established as, toxic to reproductionsuffering from congenital heart defects compared with children of parents in other professional groups (Olshan et al. 1989).

It has also been established that during their normal duties in connection with callouts, firefighters are  subjected to substances that are suspected to be, or have been established as, toxic to reproduction (McDiarmid et al. 1991).

Some substances that are formed in fires (e.g., acetaldehyde and formaldehyde) react with one another or with e.g., water (saliva or mucous in the airways). These substances can either remain in the upper respiratory tract or be transported down to the stomach and lungs and have harmful effects. Some substances (such as isocyanates from glue, plastic and paint) can evoke asthma, allergies and other hypersensitivity, even for those exposed to low quantities if this occurs repeatedly.

Free radicals are formed in fires involving normal construction materials. Free radicals are very reactive; i.e., they easily react with other substances, and they have a harmful effect on DNA, among other things.

At the scene of a fire, firefighters are at risk of being subjected to mixtures of harmful substances from parti cles, gases and waste products that come from fire and pyrolysis. These can include heavy metals (lead, cadmium, uranium), various chemical agents(benzene, polyaromatic hydrocarbons, toluene, formaldehyde) and minerals (asbestos, silicon dioxide, silicates).

Even the fire station, where the firefighters spend a great deal of time, contains complex mixtures of substances in particle form. (LeMasters et al. 2006).

Serious illness can be the result of having been exposed to many different harmful substances. It has also been proven that combi-nations of different chemicals which are not particularly harmful individually can give rise to entirely new and very hazardous effects (Mayer 1977). Firefighters are at risk of exposure to quantities of foreign chemicals at the scene of a fire and when handling material that has been in contact with pollutants from the fire. As a rule, both the type and concentration of substances that are formed or released in the event of a fire and pyrolysis are unknown to the firefighters.

People have varying degrees of sensitivity for exposure to different chemicals and mixtures of chemicals. This means that the risk of different individuals developing illnesses due to exposure to foreign substances varies.
It is known that harmful substances are formed in fires. Different substances can become even more hazardous in combination,

Some substances formed in fires only lead t o harmful effects when they react withwater from saliva or mucous in the airways.

People have varying degrees of sensitivity and the risk of developing illnesses varies,  and firefighters at risk of exposure to these mixtures do not know what substances they are exposed to or how this affects them as individuals.

It is known that firefighters as a professional group are affected by certain illnesses, but it is not known which fire- fighters are affected. It has been established through previously mentioned meta studies (LeMasters et al. 2006) that firefighters run a higher risk of certain types of cancer. What is less researched is what other illnesses can arise as a result of firefighters being subjected to foreign substances.

More studies are required to investigate the connection between the firefighting profession and serious chronic or sub-chronic diseases other than cancer.

Difficult to make early and reliable diagnoses
The only reasonable way to determine how people are affected by combinations of unknown substances suspected to be included in complex mixtures in different concentrations is via tests or taking samples. The problem with some of the illnesses that affect fire- fighters is that they can remain latent for a long time before any symptoms arise or are even measurable (Barry 2001).

Measuring and controlling illnesses is therefore difficult. Aside the fact that detailed health examinations can be resource-intensiveand lengthy, it is difficult to decide what should be measured and how. As the substances and consequences can be unknown, this can also mean there is a false sense of security in measuring certain substances as the most relevant tests could be those not carried out. Health examinations are necessary, but before we be gin measuring health markers, the measurements must be so reliable that they do not cause more concern in the person being examined.

Even if it is possible to measure and prove the presence of certain substances in firefighters’ bodies, it is at present difficult to predict the consequences of the combination of substances that a particular individual has been exposed to and how this affects him or her in the long term.

When discussing firefighters’ heightened risk of serious illness as a result of their work, this must always take into account the fact that everyone can contract cancer and other diseases. Cancer is found among all professional groups, and it is very difficult in each individual case to ensure that an illness which takes a long time to manifest is work-related. At the same time, the connection between the professional role of a firefighter and a heightened risk of cancer has been evidenced, so it is therefore important to ensure that firefighters are not exposed to harmful substances more than absolutely necessary.

It is difficult to predict the consequences of harmful substances in the body, even if it is possible to check
whether the substances exist in the body.