5 years after TSCA reform – Why EPA must prioritize science to protect public health

Implementation by the U.S. Environmental Protection Agency (EPA) of the Toxic Substances Control Act (TSCA) does not fully account for science or protect the public’s health, so how can EPA strengthen implementation of the law?

The Program on Reproductive Health and the Environment (PRHE) has closely monitored EPA’s TSCA implementation, submitting public comments on how inadequate scientific methods used in EPA’s risk evaluations have led to an underestimation of risk for the chemicals EPA has evaluated to date.

We will share what we’ve learned, along with other science policy experts during a panel discussion, “5 Years After TSCA Reform: Strengthening Health Protection through Science on Friday, June 25th at 9:30am PST / 12:30pm EST.

Bottom line: EPA’s chemical risk evaluations under TSCA will continue to be inadequate until methodological, scientific, and technical problems are consistent with best scientific principles for risk evaluation and for systematic review. These key scientific issues include:

EPA must follow recommendations from the National Academies of Science, Engineering, and Medicine (NASEM) and implement a systematic review method that has been tested and is consistent with best practices, including the Navigation Guide developed by UCSF

The NASEM recently reviewed the TSCA method and stated that EPA should “step back from the approach that it has taken and consider what components of the OHAT, IRIS, or Navigation Guide methods could be incorporated directly and specifically into hazard assessment,” because the TSCA method “does not meet the criteria of ‘comprehensive, workable, objective, and transparent.”

We urge EPA to use one or more of these methods (OHAT, IRIS and Navigation Guide) and while some important flaws remain in the IRIS systematic review method, once these are addressed we believe it should be adopted across all of EPA’s programs.

EPA must identify Potentially Exposed or Susceptible Subpopulations (PESS) based on established extrinsic and intrinsic factors that increase vulnerability and fully assess the risks to these populations

Under TSCA, EPA has an obligation to protect susceptible subpopulations from any unreasonable risks from harmful chemicals. Scientific evidence demonstrates that intrinsic factors (e.g. age, pre-existing diseases, sex, genetic traits) and extrinsic factors (e.g. stress due to food insecurity, racism and/or poverty, geographic factors, workplace factors) can increase susceptibility to environmental chemical exposure risks.

The definition of PESS in EPA’s first ten TSCA risk evaluations fails to capture the full range of intrinsic and extrinsic factors that influence susceptibility to chemical exposures, and thus the evaluations failed to suitably account for risks to susceptible subpopulations.

EPA must include all conditions of use and all exposure pathways and consider aggregate exposures

EPA incorrectly decided to exclude certain exposure pathways from risk evaluations that may be addressed under other EPA statutes like the Clean Air Act. For example, the risk evaluation of 1,4-dioxane (a carcinogen) did not consider exposures in drinking water, which is especially concerning because EPA does not regulate 1,4-dioxane in drinking water. EPA also decided not to consider exposure to 1,4-dioxane used in industrial and commercial products such as detergents used in hospitals. These and similar decisions mean that EPA underestimated the risk posed by 1,4-dioxane and also means that EPA will not regulate the excluded exposures under TSCA.

TSCA also requires EPA to eliminate the unreasonable risk posed by a chemical substance from “the manufacture, processing, distribution in commerce, use, or disposal of a chemical substance or mixture, or any combination of such activities.” However, EPA failed to account for the combination of oral, inhalation and dermal exposures, again underestimating the risk to human health.

EPA must require data that are sufficiently comprehensive and sensitive to understand hazard and prevent harmful health effects of chemicals

In every TSCA risk evaluation EPA has proceeded without adequate data, and in several it lacked sufficient information on critical health endpoints. TSCA gives EPA authority to require testing from chemical manufacturers and processors to generate information needed to evaluate the risks of the chemicals. However, to date EPA has issued testing requirements that have been narrow in scope and failed to require critical toxicity studies. EPA must fully utilize the new authorities in sections 4, 8 and 10 of amended TSCA to address persistent data gaps and ensure adequate health effects information for decision-making.

TSCA risk evaluations must provide additional information to help ensure that TSCA regulations “appropriately benefit and do not inappropriately burden disadvantaged, vulnerable, or marginalized communities”

President Biden’s memorandum on “Modernizing Regulatory Review” indicates the intent of his administration to promote “social welfare, racial justice…and the interests of future generations” and the intention to develop “procedures that take into account the distributional consequences of regulations…to ensure that regulatory initiatives appropriately benefit and do not inappropriately burden disadvantaged, vulnerable, or marginalized communities.”

Disproportionate chemical exposures affect the well-being of disadvantaged and susceptible communities and can pose systemic barriers to opportunities for people of color.

TSCA risk evaluations have not provided robust analyses to assess the distributional consequences of TSCA risk management regulations. The demographic characteristics of exposed populations (race/ethnicity, income group, and life stage) should be reported to the extent possible in each risk evaluation. For example, EPA should use census data for populations living near facilities associated with exposure such as a factory, or a chemical storage facility near a drinking water source for analysis of how risk management alternatives will benefit disadvantaged, vulnerable, or marginalized communities.

Now is the time to put science and public health front and center at EPA to ensure that the most significant and pervasive threats to health from harmful chemical exposures are properly addressed. We urge EPA to take advantage of the monumental shift in public health priorities and use the best available science when conducting future risk evaluations under TSCA.