The European Union operates under the precautionary principle, which assigns the burden of proving that something is not harmful to those responsible for that something (when concrete scientific evidence about that something does not exist).
In the United States, the opposite holds true. Often, manufacturers are self-policing (the pharmaceutical companies are the most obvious example) and the burden of proof rests with the public or advocacy groups to show that something is harmful.
The results are gaping policy differences. For example, the European Union just banned the use of bisphenol-A (BPA) in baby bottles (starting in June 2011), while in the United States, the American Chemistry Council, the lobbying arm for several chemical behemoths, prevented the inclusion of a similar ban in the Food Safety Modernization Bill that is on the verge of becoming law.
Unfortunately for Americans and our health, similar policy discrepancies exist in regard to hormones and antibiotics administered to livestock, genetically modified crops and petroleum-based artificial colorants.