Toxic Substances Control Act and Nanotechnology

The Toxic Substances Control Act (TSCA) is the U.S. environmental legislation most immediately relevant to nanomaterials. Enacted in 1976, it grants broad authority to the Environmental Protection Agency (EPA) to regulate hazardous materials, but sets stringent conditions on the use of those powers. In particular, the burden of proof for action on existing chemicals (those listed in the TSCA inventory) is substantial, much more so than that for “new” substances. This distinction is particularly salient to nanomaterials, because many are molecularly identical to materials already present in the TSCA inventory, even though the properties of the nanoscale materials may be very different than those of the same substance in bulk.

Firms that wish to introduce new chemicals must notify EPA prior to marketing them through a process called Premanufacture Notice (PMN). The agency has 90 days to review the material, and the authority to require additional data, or usage restrictions by issuing a Significant New Use Restriction (SNUR). To date, EPA has issued several SNURs for buckyballs and carbon nanotubes, because it considers these as “new” allotropes (structural configurations at the molecular level) of carbon, and thus “new” chemicals under TSCA. TSCA does give EPA authority to issue SNURs for classes of chemicals, and the voluntary Nanomaterials Stewardship Program (NMSP) is partly designed [Page 765]to gather information that might feed into future rule making. However, EPA has determined that nanomaterials whose molecular structure is unchanged at the nanoscale do not constitute new chemicals under TSCA. Thus, PMNs are not required for nanoscale silver, titanium dioxide, and gold, among many others, and any regulatory action EPA might take under TSCA would have to satisfy the evidential standards for existing chemicals.

These standards include the need for EPA to demonstrate that an existing substance presents an unreasonable risk in order to justify regulatory measures, including any mandates for manufacturers to conduct additional risk assessments. Additionally, the agency must consider the economic and social implications of any proposed action; in this sense, “unreasonable risk” is a risk-benefit standard.

Finally, EPA must show that any recommended regulation is the least burdensome avenue to achieve the desired results, and that no other statute could better address the concern. A federal court ruled against a proposed ban on certain types and applications of asbestos on the latter grounds in 1989, and the agency has not attempted to invoke this particular authority over existing chemicals since.

TSCA has been criticized as inadequate to meet the regulatory challenges posed by nanomaterials, and the 21st century in general. The legislation is more than 30 years old, and critics argue that the modern pace of innovation increasingly outstrips the capacity of list-based approaches such as the TSCA. These critiques are particularly salient in light of recent European actions, most notably the ongoing implementation of the Registration, Evaluation, Authorization, and restriction of Chemicals (REACH) legislation. REACH takes a more comprehensive approach to chemical regulation than does TSCA, and largely eliminates the distinction between new and existing chemicals.

The differences between the two regulatory schemes extend far beyond nanomaterials, and there is some confusion and controversy about the efficacy of REACH at the nanoscale. REACH has become an important element of the context for TSCA implementation with respect to nanotechnologies, and is a source of pressure for TSCA reform. TSCA is also a good example of the power of nanoscale science and engineering to challenge existing paradigms. A portion of this is novel; uncertainties about the parameters of nanoscale toxicity are forcing a reconsideration of prevalent risk assessment procedures and practices. Other aspects are not new, but rather highlight preexisting issues with TSCA and related legislation. Innovations at the nanoscale may thus be catalyzing parallel inventions within regulatory domains. TSCA, and calls for reform thereof, are likely to emerge as battlegrounds in the near future, prompted in part by the increasing importance of nanotechnologies.

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