This article examines our emerging knowledge base about the hazards of nano-sized particles (NSPs), focusing on risks posed by two types of exposure, inhalation of NSPs and topical application of products containing NSPs. It examines why the current regulatory framework is inadequate to respond to these risks and why regulators believe their hands are tied until new legislation is enacted. It then argues that this regulatory inaction leaves a significant role for the private insurance market, but that regulators should support this market in tangible ways, such as requiring federal grant recipients to carry commercial liability policies that would protect the public from potential adverse consequences