Public perceptions of risk have often been dismissed on the basis of "irrationality", and have tended to be excluded from policy processes by risk assessors and managers. People's responses to different risks are determined by psychological factors. The technical risk estimates traditionally provided by experts do not influence people's behaviours and responses in the same way as their risk perceptions. Some concerns are very specific to particular hazard. It is also important to communicate the difference between probability and variability associated with risk estimates. Risk communication must take account of the actual concerns of the public (for example, potential for negative environmental impact, unintended human health effects, or vulnerable groups within the population). When the public want information about a risk, they prefer a clear message regarding risks and associated uncertainties, including the nature and extent of disagreements between different experts. Furthermore, societal priorities for risk mitigation activities may not align with those identified by expert groups. Dismissing the former as irrelevant may result increased distrust in the motives of regulators and industry, with consequences for public confidence in regulatory activities linked to public protection. Awareness and understanding of public concerns must be the basis of an effective risk management strategy.