The purpose of this review was to determine how effectively the U.S. Environmental Protection Agency (EPA) is managing the human health and environmental risks of nanomaterials. Nanomaterials are currently used in a wide variety of applications, including consumer products, health care, transportation, energy, and agriculture. The Agency considers nanomaterials as chemical substances that are controlled at the scale of approximately one-billionth of a meter. EPA has the authority, through several environmental statutes, to regulate nanomaterials. Although the development of nanomaterials and nanomaterial-enhanced products is expanding rapidly, the health implications of nanomaterials have not yet been determined.