Regulation of carcinogenic food additives and drugs in the US.

The four components of the process by which a decision is made about the acceptability of human exposure to a chemical are outlined. The quantity and quality of the data that are required have increased considerably in recent years, and the standards governing the conduct of the studies done to obtain them have become more stringent. Thus, many chemicals now in widespread use were admitted on the basis of evidence that is now considered woefully inadequate; the steps being taken in the US to remedy this situation are described. Since such testing is long and expensive, four regulatory agencies have joined together to develop guidelines that can be used by each. The interpretation of data presents yet another problem. Further, what constitutes adequate evidence for safety is a matter subject to wide ranges of opinion: this is illustrated by the example of cyclamate. The difficulties of extrapolating results to actual situations are outlined; and the limitations of the usefulness of experimental testing are pointed out. Determination of an acceptable ratio between benefits and risks depends on a wide variety of factors, and regulatory decisions in this regard thus depend on several kinds of scientific judgements and on policy decisions based on cultural aspects.