Nanoparticles are so unimaginably small that 800 to 80,000 of them can line up across the breadth of a single human hair. Although some nanoparticles have always been found in nature, the invention and production of new forms is a booming industry. For example, zinc oxide and titanium dioxide in nano form render sunscreens transparent instead of pasty white. Nanoparticles in food packaging materials retard spoilage.
On June 9, the White House Office of Science and Technology Policy issued a set of principles meant to lay the groundwork for regulating nanoparticles to protect public health and the environment without stifling innovation. The same day, the U.S. Environmental Protection Agency and Food and Drug Administration published proposed definitions of nanomaterials, as a first step toward evaluating potential safety concerns about them.
The Environmental Working Group has submitted formal comments urging the FDA and EPA to broaden their definitions of nanomaterials to assess those concerns fully.
EWG believes that EPA’s proposed plan to collect information about nanomaterials in pesticides defines particles too narrowly. EWG has advised the agency to broaden its criteria to cover particles larger than 100 nanometers (nm) in at least one dimension because some larger particles may exhibit toxicity effects similar to smaller ones. EWG opposes EPA’s proposal to exempt naturally occurring nanomaterials such as some minerals found in soil. Finally, EWG urges EPA to require companies to disclose their own safety assessments of nanoparticles and to conduct additional monitoring of their long-term effects on human health and the environment.
FDA’s proposal focuses on nanomaterials in food, food packaging, drugs, cosmetics, and medical devices. Its draft definition of nanomaterial is more comprehensive than that proposed by EPA. However, FDA’s definition arbitrarily sets an upper limit of 1,000 nanometers, or one micrometer. Some particles larger than that exhibit properties like those of small particles. For example, several forms of zinc oxide used in sunscreen are larger than a micrometer, yet in some ways they behave like the smaller particles FDA proposes to evaluate.