TSCAblog™

Jeffery Morris, Former OPPT Director, Examines TSCA as a Gap-Filling Statute
Posted on October 13, 2020 by Lynn L. Bergeson

By Lynn L. Bergeson and Carla N. Hutton

After reading the article below by Jeffery Morris, former Director of the U.S. Environmental Protection Agency’s (EPA) Office of Pollution Prevention and Toxics (OPPT), we were inspired to post it.  We appreciate having the opportunity to share his analysis with our audience.

TSCA as a Gap-Filling Statute:  Potentially Exposed and Susceptible Subpopulations

By Jeffery Morris, PhD

In its response to public comments on the scope documents for its next twenty chemical risk evaluations conducted under the Toxic Substances Control Act (TSCA), the US Environmental Protection Agency (EPA) has asserted that TSCA is a “gap-filling statute” for the regulation of chemical substances in the United States (US EPA, Summary of Public Comments Received on the Draft Scopes of the Risk Evaluations for Twenty Chemical Substances Under the Toxic Substances Control Act (TSCA), August 2020, p. 13).  This assertion relates to the regulatory nexus between TSCA and other federal statutes.  At issue regarding regulatory nexus is whether TSCA’s role is to:  (1) fill gaps where issues are not addressed by other laws that regulate chemicals1, (2) serve as the nation’s primary and preeminent statute for chemicals, or (3) operate somewhere between these two positions.  Inherent in the TSCA-as-gap-filler position is the view that federal laws should work together to advance the public welfare, and that different environmental statutes have their own strengths in how they govern the impact of chemicals on people and the environment.

TSCA requires the consideration of potentially exposed or susceptible subpopulations in the EPA’s evaluation of chemicals.  While TSCA is not the only environmental law with provisions for susceptible or vulnerable subpopulations, the direct, repeated emphasis across multiple sections of the law that the EPA consider potentially exposed or susceptible subpopulations may be unique in US environmental law.  Therefore, how the EPA meets this requirement with respect to other laws’ treatment of such populations is an important consideration for regulatory nexus.  Key questions regarding regulatory nexus and TSCA’s role are how to go about identifying whether other statutes leave gaps in this area for TSCA to fill and if they do, how those gaps should be filled in the EPA’s chemical evaluations.

The recently released final scope documents and the accompanying response-to-comments document do not fully answer these questions, including regarding comments that have been raised about how the EPA will apply exposure and susceptibility considerations to people living in communities located near high concentrations of chemicals-related activity.  My hope is that exploring these questions now can help inform a path forward for further addressing comments the EPA has received on potentially exposed or susceptible subpopulations as the twenty draft risk evaluations are developed, as well as in scope documents for future chemicals brought into the TSCA prioritization process.

In its response to scope document comments, the EPA makes two important statements regarding the regulatory nexus issue as applied to potentially exposed or susceptible subpopulations.  The first, on page 13, is that “EPA believes that coordinated action on exposure pathways and risks addressed by other EPA-administered statutes and regulatory programs is consistent with statutory text and legislative history, particularly as they pertain to TSCA’s function as a ‘gap-filling’ statute ….”  In the second statement, also on page 13, the EPA adds that “[t]o the extent that specific exposure pathways are not under the jurisdiction of other EPA-administered statutes and associated regulatory programs, EPA plans to evaluate those exposures in the risk evaluations for the individual substances.”

The first statement’s focus on “coordinated action” between laws and regulations with respect to chemical evaluation and management is a crucial consideration for regulatory nexus.  Coordination by the EPA’s Office of Chemical Safety and Pollution Prevention (OCSPP), which administers TSCA, with other EPA offices that manage statutes that address chemicals, as well as with other federal agencies that implement laws impacting chemicals, is good government practice.  What is missing from the final scope documents, and therefore would be a valuable addition to the chemical-specific dockets, is a detailed description of the type of coordination cited in the response to comments.  Ideally, this description would appear in the scope documents, but for these twenty chemicals an addition to the dockets would be helpful.  For example, the EPA could strengthen its explanation of whether potential exposures or susceptibilities are based on geography (e.g., exposures are higher in a particular location), biology (e.g., a particular population has a genetic or otherwise biologically based predisposition to suffer adverse effects from exposure to a chemical), or cultural/societal factors (e.g., a cultural or community practice results in exposure potential greater than in the general population, or an attribute of the subpopulation’s location in society, such as having low income or poor access to health care, creates susceptibilities to adverse effects from chemical exposure).

Because some comments on community exposures refer specifically to 1,3-butadiene, it is a useful example to illustrate the challenges and opportunities presented by the coordination the EPA is conducting within the regulatory nexus construct; it also can illustrate what I mean by a detailed description of cross-office coordination on potentially exposed or susceptible subpopulations.  This example looks at just one of 1,3-butadiene’s uses:  in the production of tires.  Under its Clean Air Act (CAA) authority, the EPA’s Office of Air and Radiation (OAR) conducted a Residual Risk Assessment for the Rubber Tire Manufacturing Source Category in Support of the 2020 Risk and Technology Review Final Rule (EPA-HQ-OAR-2019-0392-0047, February 2020) that includes 1,3-butadiene within this source category, among numerous other chemical substances designated as hazardous air pollutants (HAP).  This assessment supports a July 24, 2020, final rule, National Emission Standards for Hazardous Air Pollutants: Rubber Tire Manufacturing Residual Risk and Technology Review (EPA-HQ-OAR-2019-0392; FRL 10008-48-OAR, 85 FR 44752, July 24, 2020).

The coordination challenge, therefore, is to crosswalk the CAA review, which covers numerous HAPs within one sector, with a TSCA risk evaluation covering the conditions of use of a single HAP chemical across multiple sectors.  On page 49 of the 1,3-butadiene TSCA scope document, the EPA states that air emission pathways are covered under the CAA (Final Scope of the Risk Evaluation for 1,3-Butadiene, EPA Document # EPA-740-R-20-011, August 2020).  It would be useful for the 1,3-butadiene record to include a table and/or narrative that describes how, for its TSCA coordination on the consideration of potentially exposed or susceptible subpopulations, OCSPP evaluated the 1,3-butadiene conditions of use against the respective source category-based and any other analyses conducted by OAR that included 1,3-butadiene.  Such a crosswalk could serve as a best practice for application of regulatory nexus analysis in the implementation of TSCA.  It would also aid in transparency to the public around a very complex but important concept:  that although different environmental statutes may use different approaches (e.g., sector or source category versus individual chemical analysis), it is possible to coordinate their respective contributions to chemical evaluation and management so that, if gaps exist, TSCA can play its appropriate role in health and environmental protection.

For instance, OAR’s 2020 final rule states that “the percentage of the population potentially impacted by Rubber Tire Manufacturing emissions is greater than its corresponding nationwide percentage for: African Americans (25 percent for the source category compared to 12 percent nationwide) and below the poverty level (21 percent for the source category compared to 14 percent nationwide)” (page 44759).  Strong coordination between TSCA and the CAA would suggest that such information obtained through CAA activities would be helpful to OCSPP in determining how to address the “potentially exposed or susceptible subpopulations” considerations required under TSCA section 6, including as they may apply to TSCA’s gap-filler role in addressing comments to the 1,3-butadiene scope document concerning disproportionate exposure to communities located near high concentrations of chemicals-related activity.

This consideration leads to the EPA’s statement in its response-to-comments document that where there is not overlap with another regulatory jurisdiction, the EPA will evaluate the exposures.  Using the above TSCA-CAA coordination example for 1,3-butadiene, a question for OCSPP could be whether the TSCA requirement that the EPA consider potentially exposed or susceptible subpopulations in its risk evaluations is covered by the work done by OAR on 1,3-butadiene, specifically with respect to commenters’ input on community-based impacts.  One would assume “covered” to mean that this particular aspect of TSCA’s potentially exposed or susceptible subpopulations requirement has been evaluated and addressed in OAR’s CAA activities, and therefore can be excluded from the 1,3-butadiene risk evaluation.  However, if the CAA has not addressed this particular TSCA requirement in a manner or to an extent intended by the best read of TSCA’s language regarding the consideration of those potentially exposed or susceptible subpopulations in a particular chemical risk evaluation, then there exists a gap that TSCA, as a gap-filling statute, should address.

The manner in which a TSCA risk evaluation fills any identified gaps is also important.  This again will require careful and transparent coordination and analysis between statutes.  In its chemical risk evaluations, EPA would presumably want to fill gaps in ways that meet the specific requirements of TSCA for potentially exposed or susceptible subpopulations, without doing so in a manner that is at odds with other statutes’ treatment of a chemical substance under TSCA evaluation.  Not only would this careful gap filling be in general sound government practice, but it also would help avoid difficulties if the risk evaluation identifies unreasonable risks that the EPA determines, under TSCA section 9, should be addressed under a law other than TSCA.

The 1,3-butadiene example shows how greater explanation, preferably in scoping documents, on how the EPA coordinates among its offices and other agencies to make regulatory nexus decisions for TSCA risk evaluations can not only provide greater transparency to the public on individual chemical evaluations, but also can inform broader discussions on regulatory nexus by showing how such coordination can identify gaps that TSCA is best situated to fill.  For some chemicals, it may be the case that other statutes have already adequately assessed the risks to potentially exposed or susceptible subpopulations, obviating the need for additional analysis in a TSCA risk evaluation.  However, the mere existence of another statute with jurisdiction over a particular environmental pathway or human exposure scenario for a chemical substance subject to TSCA review should not lead to an a priori assumption that there is not an evaluation gap for TSCA to fill.  Any assumptions about other statutes’ coverage of TSCA’s chemical evaluation requirements should be explored, tested, and fully described in TSCA chemical scope documents or elsewhere in the risk evaluation record.  This is particularly important with potentially exposed or susceptible subpopulations, given TSCA’s unique approach to requiring their consideration in chemical prioritization, evaluation, and management.  I would argue that a good starting point for articulating TSCA’s gap-filling role is in the application of these requirements to people living near high concentrations of chemicals-related activity.

1  By “chemicals” I refer in this article to chemicals regulated under TSCA, and not to chemicals that are regulated under other federal statutes, such as pesticides, drugs, and food additives.

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