When Are Nanoparticles New Chemicals? A Size-Based Criterion for Molecular Identity
A.M. Boyd, T. Hester, V.L. Colvin
Rice University, US
Keywords: nanomaterials, TSCA
Abstract:U.S. environmental laws will treat nanomaterials very differently if regulators conclude that nanomaterials are entirely “new chemicals” rather than simply novel versions of existing chemicals. These laws and regulations, however, do not provide a clear standard on when a nanomaterial might constitute a new chemical. When federal agencies have tried to answer this question, they have looked to prior legal decisions and guidance as to whether other novel chemicals in arguably similar circumstances were new chemicals. These governmental efforts have not attempted, however, to devise or outline a scientific test or procedure that directly assesses whether a certain nanomaterial has characteristics that would render it a new chemical for regulatory purposes. Here we propose a simple and quantifiable criterion for determining whether a nanoparticle’s size or atomic composition should dominate considerations of its identity.