The relationship between the precautionary principle and World Trade Organization (WTO) rules is an area of potential conflict. The precautionary principle legitimizes the need to act (for example, to ban or to restrict a product), even in the absence of conclusive scientific evidence, and even on the basis of a qualitative but not quantitative scientific assessment of risk, in order to protect public health or the environment. The precautionary principle is thus by definition an issue where available evidence does not permit a full risk assessment approach on the lines embedded in Article 5 of the Sanitary and Phytosanitary Agreement (SPSA) which requires justification on the basis of scientific evidence. Article 5.7 of the SPSA does however embed the precautionary approach in WTO, at least for health-related issues. The 1999 dispute between the US and EU on imports of beef treated with growth hormones illustrated an international problem arising from different assessments of the precautionary issue. Genetically modified food raises similar issues.
In 1998, the highest French court invoked the precautionary principle when it suspended commercialization of three GM corn varieties.
To gain public trust, the US government should convene a national dialogue to define a precautionary approach for resolving trade and environment disputes. A national definition should recognize governments' right to protect health and the environment even when, as is the case with many environmental pollutants, less than full information is available, and especially when postponing decisions in order to obtain more information could expose people and ecosystems to potential harm. The US should commit to apply this approach to its activities in the WTO, including dispute settlement, and urge others to do so as well.