Earlier this year, the twenty-seven European Union (EU) governments reached a consensus to institute new criteria that could ultimately blacklist around twenty-two chemicals--about fifteen percent of the EU pesticides market--used by the agricultural and pest control industries. The EU regulation embraces a more restrictive hazard structure based upon the "precautionary principle," which contends that some chemicals are intrinsically dangerous at any level, even absent definitive risk data. The new ban, to be phased in beginning in 2011, has been challenged by some policy experts who are concerned that it could damage food security while yielding limited or no health benefits. Opponents also argue that the measures could lead to unintended consequences such as damaging disease-control efforts in developing countries. Proponents of the new pesticide regulations hail them as necessary precautions for addressing the unknown cumulative effects of chemical residues.

This new EU decision breaks with long-standing protocol in the United States and many other countries that rely primarily on risk standards, which hold that chemicals are considered safe if studies on animals reveal no known risks at the levels found in food. Does the EU's new approach to pesticides place the scientific method in jeopardy? What are the implications of the precautionary standard, which may shape future regulations in many countries, including the U.S.?