On June 21, 2018, the U.S. Environmental Protection Agency (EPA) issued guidance intended to “assist companies in creating structurally descriptive chemical names for chemical substances whose specific chemical identities are claimed confidential, for purposes of protecting the specific chemical identities from disclosure while describing the chemical substances as specifically as practicable, and for listing substances on the Toxic Substances Control Act (TSCA) Chemical Substance Inventory.”  EPA states that the guidance, entitled Guidance for Creating Generic Names for Confidential Chemical Substance Identity Reporting under the Toxic Substances Control Act, was developed in response to the requirement under new TSCA Section 14(c)(4) that EPA “develop guidance regarding – (A) the determination of structurally descriptive generic names, in the case of claims for the protection from disclosure of specific chemical identity…” and the requirement under new TSCA Section 14(c)(1)(C) that submitters who assert a confidentiality claim for a specific chemical identity must include a structurally descriptive generic name developed consistent with EPA guidance.  The guidance updates and replaces the 1985 guidance published in the TSCA Inventory, 1985 Edition (Appendix B: “Generic names for Confidential Chemical Substance Identities”).  EPA states that, also consistent with 14(c)(4) and 14(c)(1)(C), EPA will be reviewing generic names upon receipt in TSCA filings where chemical identity is claimed as confidential for consistency with the guidance.  EPA encourages companies to consult the Agency’s Office of Pollution, Prevention, and Toxics (OPPT) if they feel that it will be necessary to mask more than one structural element of a specific chemical name to mask a confidential chemical identity.

In contrast to the 1985 guidance, which distinguished only between constructing generic names for class I and class II chemical substances, the new guidance specifically distinguishes between inorganic chemical substances, class I organic chemical substances, and class II organic chemical substances.  Suggestions and examples for masking elements of inorganic substances are detailed in a separate section from the guidance for class I and class II organic chemical substances.  The new guidance also specifically refers to Unknown or Variable composition, Complex reaction products and Biological materials (UVCB) substances when addressing class II organic chemicals, unlike the 1985 guidance.  In addition, the new guidance lists an additional structural element of a class I organic chemical substance that can be masked when creating a generic name:  stereochemical or isomeric identifiers.  Other, minor, additions include more detail on the generic descriptors that can be used to mask a parent structure describing a specific chemical class or an attached chemical group for a class I organic chemical substance, more examples of generic names for a class I organic chemical substance, and many more examples of generic names for a class II organic chemical substance. 

Commentary 

The requirement under Section 14 of new TSCA that generic names be structurally descriptive does not constitute a substantive shift away from previous EPA guidance on generic names.  The 1985 guidance illustrates generic names as being crafted by masking a single structural feature of the specific substance name.  Masking multiple structural features, which may cause a chemical name to no longer be structurally descriptive, is permitted only if the submitter justifies the need in writing for the additional masking.

Similarly, the new guidance focuses on generic names that mask a single structural feature only and encourages companies to consult OPPT if they wish to do multiple masking of a generic name.  The major difference between the two appears to be not the type of generic name that EPA advises submitters provide, but the strictness with which EPA determines what constitutes an acceptable generic name.  The many new examples provided for class II organic chemical substances, in particular UVCBs, and inorganic substances, suggest that these chemical classes in particular are ones for which EPA will be expecting more specific generic names than those submitted according to the 1985 guidance.  Additionally, EPA’s specific identification of stereochemical or isomeric identifiers as a structural feature that can be masked suggests that, while EPA may previously have allowed the masking of stereochemistry along with the masking of an additional structural feature without requiring additional justification (i.e., without considering it to be multiple masking), this will no longer be the case going forward.

EPA’s new approach is perhaps best summed up by the guidance that submitters should begin with the substance’s specific name and mask only the elements that are confidential rather than starting with a very generic name and adding structural information.  If more than one level of masking is necessary, written justification will be required. 

Submitters should expect significant scrutiny of generic names and may find premanufacture notifications (PMN) being rejected as invalid if the generic names are too generic.