A science perspective

Four scientists talk you through about risk perception applied to work-related cancer, the importance of behavioural psychology, an inductive way of thinking and developing less harmful conditions for Bitumen workers.




‘The outside world needs to see you as one unified group’


Jop Groeneweg  – Assistant Professor at Leiden University, Netherlands


Involved with Cognitive psychology, specialized in risk perception and occupational safety


Vision  The human brain has two different responsive speeds: Groeneweg refers to these as the hare-brain and the tortoise-brain. The hare-brain gives you a quick (if not always correct) understanding of how to respond to something; the tortoise-brain kicks in much slower to analyse a given situation. An encounter with carcinogens, Groeneweg explains, ideally should trigger an immediate warning response from the hare-brain – but our brain is not automatically activated by every potential risk we encounter. Visibility, repetition, availability and clustering do influence the hare-brain, as does public outrage. These factors may help to change the risk perception of carcinogens. Referring to Jaws, the 1977 Spielberg movie that has given thousands of people a very deep and immediate fear of sharks, Groeneweg points out that there is little relation between actual risk and perceived risk. “What you need to manage”, he urges, “is the perception of the risk: to create a situation in which alarm signals in people are immediately triggered.”


Future  “One big threat to acceptance of carcinogens as a risk, is that people feel that they are part of the job; that this is a voluntary risk that they have to take in order to create a living for themselves and their families. The difference in risk acceptance between voluntary and involuntary risk is about a factor thousand. It’s also a matter of source credibility. You have to ask yourselves very carefully: who do I get to tell the story? Who will I make owner of the problem? Many of the issues surrounding carcinogens are not completely known. There are some discussions about statistics, and you might go into an endless discussion about what the actual risk is. But what you have to realise is that one thing that really undermines source credibility is lack of consensus. Whatever you do, the outside world needs to see you as one unified group of people. If you don’t go out in unity the outside world will perceive the actual risk as much lower. Make carcinogens visible, keep repeating your message, and make sure that the nature of the risk is such, that people are thoroughly worried by them”, concludes Groeneweg.

'Old habits die hard'

Bert Pol  – Founder of Tabula Rasa


Involved with behavioural change and communication


Vision  We still have much to do to reduce work related cancer and create safer conditions for workers. It is not simply enough to give information to workers. It is about changing workers habits. As the saying goes, 'old habits die hard': if we are to prevent work-related cancer, old habits need to change and the desired behaviours need to be continually reinforced. One of the main challenges, we face in the workforce, is ensuring that the right equipment will be worn by workers. Workers need to be encouraged to change their habits in a positive manner, rather than in a negative manner. That is, workers need to be nudged towards positive behavioural change. Education is of course the first step, but then steps need to be put in place to prevent relapsing back to the old, bad and dangerous habits. Problems may arise when workers may be distracted, thinking about something else, or, perhaps, their team-leader may be setting a poor-example.


Future  How can poor behaviour be prevented and the desirable behaviour encouraged? A combination of strategies needs to be used in order to promote safer practices. Social influence is an important factor. People will often act in a similar manner to how their peers are acting. Nudging is a useful strategy, for example through changes in the physical environment. For example, when lines are placed on the floor, indicating where the stairs are, people are more likely to take the stairs, rather than use a lift. Such a practice can easily be applied to the workplace. For example, lines could be placed on the floors of change rooms pointing towards the safety equipment that workers must wear. People are easily influenced when they are not concentrating on our behaviour. So, reminders are necessary. In the case of unsafe student homes, for example, a simple wall sticker of a fire alarm was enough to encourage cleaner and tidier homes to avoid fire. This was a simple change, but it was an approach based on evidence. In the workplace, the challenge is to make the desired behaviour the default option. Conditions need to be created so that workers never want to enter the workplace without their appropriate safety equipment. This would mean that that desired behaviour has become routine and a normal part of one's working life. Evidence based research is useful to change bad and dangerous habits. Simple changes can promote and stimulate new and safer workplace routines. The challenge, however, is to make sure that over time, workers do not slip back into the old habits.


‘Structural cooperation on identification, evaluation and control’

Lode Godderis  – Professor at the Centre for Environment and Health of the KU Leuven, Belgium


Involved with early warning systems to prevent occupational cancers


Vision  In general, cancer risk assessments follow a deductive reasoning, in which a conclusion logically follows from a premise. An example of this reasoning: Polycyclic Aromatic Hydrocarbons are carcinogenic, so if workers are exposed to PAH, they have an increased cancer risk. Godderis: “When we use deduction, we reason from general principles to specific cases: like applying a mathematical theorem to a particular problem, or citing a law of physics to predict the outcome of an experiment”.


Since the outcome of deduction largely depends on the basic assumption, it is necessary that we are sure about the basic premise. This is a problem in cancer risk assessment, since workers are exposed to thousands of agents of which we do not know the carcinogenic properties. To overcome this problem Godderis advocates to introduce an inductive way of thinking, working the other way around: starting from clinical observations and early effect monitoring. “From these observations, we can look for patterns and (ir)regularities, and formulate an hypothesis that one can work with”, says Godderis. This would eventually conclude with the development of general theories, or the drawing of conclusions.


Future  It is necessary that we carefully follow-up trends in health of workers, and install early warning systems. Compare it with pharmacovigilance: drugs have undergone very extensive assessments and testing before entering the market, but unknown or unpredicted side effects are still reported often. Accordingly, Godderis pleads for OSHvigilance, which he defines as the science and activities relating to the detection, assessment, understanding and prevention of adverse effects or any other work-related problem.

Action is needed. Godderis advocates structural cooperation on identification, evaluation and control between EU Member States. “Part of this is prevention, but we also have to try and recognize clinical effects as soon as possible.”

‘Implementing the results in praxis’

Reinhold Rühl  – statutory accident insurance for the construction industry, Frankfurt, Germany


Involved with The German Bitumen Forum 


Vision  Providing a forum for makers and workers of bitumen products: including paving companies, roofers and construction companies. When initial limit values were set, the exposure data was only based on the aerosals and vapors from hot bitumen. The GBF thus started a more comprehensive measurement program.


Future  There needs to be increased cooperation between stakeholders throughout Europe. This is no longer solely the German Bitumen Forum as such, but involves much Europe-wide cooperation and collaboration. Evaluation means not only comparing the exposure with limit values, but implementing the results in praxis. The German Bitumen Forum has promoted the use of warm-mix asphalt. This has several benefits: it has lower-energy consumption, reduced C02 in production, lower-emissions at the mixing plant and emits fewer vapours and aerosols. The warm-mix has now been 'exported' to the US. Now, 30% of asphalt in the US is warm-mix. The German Bitumen Forum is confronting related questions such as: is the oxidised bitumen in the US and Europe the same; what is the difference between semi-blown and oxidised bitumen?


article by REINHOLD RÜHL