SRA-E Lisbon 2017

In large industrial of chemical fires, many people worry about the risk of developing cancer, even at a great distance from the fire. In addition, they overestimate the possibilities of environmental monitoring during the acute phase of a fire. In the Netherlands, public messages routinely contained phrases such as: ‘no hazardous substances are detected in the smoke’, ‘there is no threat to public health’, and ‘people are recommended to stay indoors and close doors and windows’. Such messages, meant to reassure the public, not only fail to adequately inform people about risk as they do not fit people’s ideas about risk, they are inherently inconsistent. That is, the advice to stay away from the smoke does not make sense unless people are also warned about the potential danger of the smoke. The above messages may even be counterproductive. When people think the messages are part of a cover up and the risks are being downplayed they can make people worry more. To improve risk communication in case of large fires, we developed alternative risk messages and tested them in a hypothetical scenario. We found that although the messages did not differ with respect to adherence to recommendations or expectations towards government actions, they differed in how they were evaluated and in how risks were perceived. Alternative messages that included the phrase: ‘all smoke is harmful’ were considered more credible but also led to higher perceptions of risk than the routine message. The same message in which a clarification of the extremely low chance of developing cancer by inhaling the smoke (i.e. comparable to smoking a few cigarettes) was added, was also considered credible but did not lead to higher perceptions of risk than the routine message. Based on our findings, we conclude that clear warnings such as: ‘all smoke is harmful’ are more informative than vague statements intended to reassure them, such as: ‘there is no threat to public health’. In addition, we recommend to include a comprehensible qualification of cancer risk in such warnings.