‘Stay clear from the smoke’: effects of alternative public messages in case of large-scale chemical fires

In the Netherlands, until recently, public messages in case of a large chemical fire, routinely contained phrases such as: ‘no hazardous materials have been detected in the smoke’, ‘there is no danger to public health’, and ‘people are recommended to stay indoors and close doors and windows’. Such messages not only fail to adequately inform people about risk, they are also inherently inconsistent. That is, the advice to stay clear from the smoke makes little sense unless there is a potential danger of the smoke. To improve risk communication in case of major fires, we developed several alternative risk messages and tested them in a digital experiment. We found that participants who read alternative messages that included the phrase: ‘all smoke is harmful’ considered the message more credible and less inconsistent than those who read the routine message. However, they also perceived the risk as higher. Participants who read an alternative message in which a qualification of the extremely low chance of developing cancer by inhaling the smoke was added, considered the message just as credible but also more clear. Moreover, they had lower perceptions of risk than those who read the alternative message without a qualification of risk. Responses with respect to adherence to recommendations or expectations towards government actions did not differ depending on the message. Based on our findings, we conclude that a public warning in case of major fires should take the public perspective into account, fitting the content s to the needs of the final receivers, and conveying a clear, consistent and informative message to enhance a basic understanding of the risk involved and the rationale of recommendations. This will not only enhance trust and credibility it may also reduce concerns and promote adherence to recommendations.