Governments in leading industrialized countries are currently relying on existing regulatory frameworks for environmental, health, and safety regulation to cover nanotechnology risks. European Union (EU) and U.S. regulators generally have concluded that any risks posed by nanomaterials can be addressed using existing frameworks, but minor adjustments to specific regulations and their implementation are currently being made in order to close any potential gaps or eliminate uncertainties. Identifying the appropriate response to uncertain risks is a difficult task for policy makers and regulatory agencies. They are faced with a high degree of scientific uncertainty and need to balance the costs and benefits of regulation as well as seeking a durable compromise between the often conflicting interests of scientific freedom, technological innovation, consumer safety, and environmental protection.

This article discusses how regulators in the United States and EU have addressed key uncertainties inherent to nanomaterial regulation in the context of chemical, food, and cosmetic regulation. We first discuss the key areas of uncertainty that plague efforts to regulate nanotechnologies and nanomaterials. We then consider how regulators on both sides of the Atlantic have responded to these uncertainties and identify common regulatory responses. We conclude by considering how regulatory responses have reduced uncertainty and suggesting further steps to effectively reduce uncertainty.