Trained first as a physician, Denis Bard was a general practitioner for 8 years. Interested then in public health issues, he got degrees in epidemiology and public health. He has been an environmental health risk assessor for more than 15 years. His research and practice have focused on risk assessments concerning free-living amebas, ionizing radiation, and chemical agents (dioxins and its related compounds, and lead). After working as a research scientist at the French national utility company, he headed and developed the Laboratory of Epidemiology at the French Institute for Radioprotection and Nuclear Safety for 4 years. He is currently a professor of Epidemiology at the École des Hautes Études en Santé Publique (EHESP School of Public Health) at Rennes (France). He is president of the IRSTEA-IFSTTAR Ethics Committee,vice-president of the Committee for Prevention and Precaution, under the aegis of the French Minister of the Environment. He co-founded (2008) and is vice-president of the French Society of Health and Environment. He has written or co-written more than 60 articles published in scientific journals and 21 books, book chapters and numerous reports for both governmental bodies and the industry.