Nanotechnology materials have numerous new properties that make them potentially useful, but it is not yet clear how these materials might act in the body or the environment. Indeed, those same unique properties could make the materials dangerous.

A report released last week by a leading nonpartisan policy institute suggests that a new law is needed to ensure that products based on nanotechnology do not harm consumers.

The proposed law, which is only outlined in the report, would place the burden on businesses to prove that new materials "do not present an unacceptable risk."

The call for a nanotech law is the latest volley in the continuing debate of how to handle safety questions raised by nanotechnology. Some argue that a law, such as the one suggested in the new report by J. Clarence Davies of the Woodrow Wilson International Center for Scholars, could harm small businesses and discourage innovation. Others, while acknowledging shortcomings in the current regulatory system, especially a lack of adequate funding, have responded to the report with calls for voluntary self-regulation by industry or a series of laws or amendments rather than a single law. And, in the past, nanotech critics have even called for a moratorium on nanotechnology development until more is known about the potential hazards involved in its use.

The Wilson report points out that existing laws and regulations were not designed with nanotechnology in mind, and also leave out categories of products, such as cosmetics, which has become an important area for nanotechnology applications. Also, right now certain chemicals are exempt from reporting requirements because they are made in relatively small amounts. But rules based on the mass of material may not apply to nanotech, where tiny amounts could be highly potent.

Richard Denison, senior scientist at Environmental Defense in Washington, DC, points out that new chemicals are grouped into toxicity categories by similarities between their chemical formulas to existing chemicals. There is not enough information to do similar grouping of nanomaterials, he says, which can have the same chemical formulas, but different shapes and sizes that make them act dramatically unlike otherwise similar materials.

Without such categories in place for nanotech, each product would have to be evaluated separately, leading to a bureaucratic nightmare. What is needed is basic science that will allow government and industries to know which particles could be dangerous and so deserve special attention, says Denison. And this means more funding for research, a need acknowledged in the report and by most involved in the debate.