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June 20, 2013

EPA Announces Availability of Fact Sheet on Isotopes

Bergeson & Campbell, P.C.

On June 19, 2013, the U.S. Environmental Protection Agency (EPA) announced the availability of a fact sheet intended to provide guidance on reporting chemical substances that are or contain different isotopes of the same elements that are already on the Toxic Substances Control Act (TSCA) Inventory. Elemental isotopes have the same number of protons and therefore are the “same” element, but differ in molecular weight and possibly other properties because of a differing number of neutrons. EPA states that the primary goal of the fact sheet “is to help the regulated community comply with the requirements of the TSCA Section 5 Premanufacturing Notice (PMN) Program for chemical substances that contain deliberate isotopic modification to an element in the substance.” The fact sheet is available online.

In the fact sheet, EPA states that chemical substances “have different molecular identities for the purposes of TSCA when they contain different isotopes of the same element or the isotopic composition of a constituent element has been intentionally changed from the naturally-occurring isotopic composition.” Accordingly, EPA states that if a specific isotope of a chemical substance is not currently individually listed on the TSCA inventory, it is subject to TSCA’s new chemical reporting requirements. Similarly, if a chemical compound contains a constituent element that differs in its isotopic state from the Inventory listing, it also is subject to TSCA’s new chemical reporting requirements. EPA encourages manufacturers to consult with EPA representatives to determine if a new chemical notice is required. In the fact sheet, EPA estimates that manufacturers should be able to compile the information necessary for a TSCA Section 5 new chemical notification within a one-year timeframe, and that EPA’s review of a submitted PMN “should be completed within the 90-day statutory review period (30 days for exemption requests).”

Elemental isotopes and chemical compounds that contain elements of differing isotopes have widespread commercial applications in medical and other technical applications, some of which (e.g., several medical applications) are not subject to TSCA’s jurisdiction. The U.S. Department of Energy is a principle supplier of isotopes for research and commercial applications. In its fact sheet, EPA identifies a limited number of elements and chemical compounds with differing isotopic states that are individually listed on the TSCA Inventory. Whether the regulated community has appreciated the distinctions EPA has made in this new guidance document is unclear.


While the “fact sheet” does not provide a context for EPA’s decision to provide guidance at this time on isotope reporting under TSCA, it seems clear that EPA believes guidance is necessary. There is little existing guidance on TSCA reporting of isotopes. The most recent explicit guidance issued by EPA was in 2008, when EPA outlined its approach to determining whether a nanoscale substance is a “new” chemical for TSCA Inventory purposes. EPA clarified then that it considers chemical substances with any differences in certain structural and compositional features to have different molecular identities, including, among others, “hav[ing] different isotopes of the same elements.” See online. On October 31, 2008, EPA issued a Federal Register notice urging carbon nanotube (CNT) producers to address their TSCA Section 5 obligations within 90 days of the notice, after which time EPA anticipated “focusing its compliance monitoring efforts” on determining whether companies were complying with the TSCA Section 5 obligations. The Federal Register notice is available online.

Years ago, EPA addressed in an enforcement proceeding whether a substance containing a distribution of isotopes in one or more of its atoms that is different from the distribution of naturally-occurring isotopes for those atoms requires TSCA notification. In In re Concord Trading Corporation, Docket No. TSCA – 94-H-19 (1997), Judge Greene rejected EPA’s motion for a summary decision on the issue of liability for TSCA Section 5 violations for importing depleted zinc oxide (DZO). Concord Trading contended that DZO was in fact listed on the Inventory since zinc oxide was listed, arguing that because these chemicals have the same molecular structure and the only distinction between DZO and zinc oxide occurs at the sub-atomic level, EPA’s assertion of liability must fail. Judge Greene concluded EPA had not demonstrated DZO was not listed on the Inventory and that “[g]reater certainty than is afforded by the current record must accompany legal conclusions of this type.” Despite the suggestion that greater clarity would be helpful, no further guidance has been issued by EPA on this issue since the 1997 decision, with the exception of the 2008 guidance noted above.

There are several notable differences between the 2008 general approach to CNTs and the “fact sheet.” First, the fact sheet is not published in the Federal Register, a distribution vehicle that arguably provides greater notice to stakeholders. Second, the fact sheet makes no mention of the enforcement consequences for failure to address any TSCA notification issues that may arise based on EPA’s “guidance” as set forth in the fact sheet. The fact sheet makes no reference to enforcement consequences although it seemingly provides a year in which to address what might (or might not) be compliance issues. At the same time, what this means to any affected regulated entity is not particularly clear as no explanation (and almost no discussion) is offered in the fact sheet. At least one interpretation is that this reflects diminished concern with the consequences of any lack of clarity on the TSCA Inventory status of isotopes. It would have been helpful if EPA had provided more of a context for issuing the fact sheet, particularly since the only reference provided is to an EPA Office of Air and Radiation website.

Further, given Concord Trading Corporation and the fact that EPA’s interpretation of isotope issues in that case was rejected, and in conjunction with very little discussion of isotopes in general over TSCA’s history, this would suggest that EPA needed to provide more background and discussion of the issue, if not submit the guidance to appropriate Notice and Comment procedures rather than release it as an informal “fact sheet.”

Manufacturers and importers of elemental isotopes or chemical compounds that contain isotopes other than the one specified as part of the compound’s TSCA Inventory listing should review this guidance carefully and follow up with EPA as appropriate. While EPA’s fact sheet makes no reference to enforcement consequences, there is no reason to believe EPA would decline to use its enforcement authority for failure to notify EPA of isotopes deemed “new” under TSCA Section 5, or at least seemingly deemed by EPA to be “new” based on the fact sheet.