EPA is going down a dangerous path on toxic chemicals

EPA has taken many important steps toward protecting people from harmful chemicals in recent years, but a disturbing pattern has emerged in the Office of Chemical Safety and Pollution Prevention in which EPA uses flawed and outdated science to estimate risk to human health. In doing so, EPA is taking several steps backwards in protecting public health and setting a dangerous precedent in the Agency’s implementation of the Toxic Substances Control Act (TSCA).

EPA’s latest draft risk evaluation of DIDP and draft hazard assessment of DINP under TSCA are a perfect example of this backwards sliding. DIDP and DINP are phthalates that are widely used as plasticizers in building and construction materials, automotive and electrical materials, and consumer products including food packaging, nail polishes, pharmaceuticals, as well as adhesives, sealants, and paints. Because of their widespread use, both phthalates have been detected in most people living in the United States.

Where the science went wrong

Both the DIDP risk evaluation and DINP hazard assessment rely on flawed methodologies and make a number of scientifically unsupported assumptions that lead to a significant underestimation of hazard and risk. Many of these scientific shortcomings are unprecedented, and have only been previously observed in EPA’s recent draft risk evaluation for formaldehyde, which we discuss here.

1. EPA ignored the most up to date health effects studies for DIDP and DINP. For example, both assessments relied on systematic review methods that lacked transparency and inappropriately excluded health effects studies without scientific justification. For both DIDP and DINP, epidemiologic studies published after 2019 were only considered if they were submitted to the EPA docket. Toxicological studies published after 2019 were not considered at all.

2. EPA’s significantly underestimated DIDP and DINP health risks by using flawed hazard assessment methods. We used methods from the World Health Organization (WHO) to quantify health risks other than cancer and found that DINP and DIDP exposure levels EPA determined to be “allowable” resulted in risk levels up to 10,000 times higher than what EPA typically considers a safe benchmark for cancer risk.

3. EPA ignored its own risk estimates in its conclusions for DIDP risks. EPA’s own estimates of high risks from numerous worker and consumer uses of DIDP were disregarded and downplayed in EPA’s risk determinations for DIDP. For example, in its evaluation of risk to workers, EPA found that 10 use scenarios resulted in estimates that were lower than its identified benchmark—a conclusion that would normally constitute “unreasonable risk” to human health. However, EPA concluded without scientific justification that only 1 out of these 10 scenarios constituted unreasonable risk—and all of the 9 disregarded scenarios were based on high-end exposure estimates. In doing so, EPA effectively ignored high-end risk estimates at the final stages of risk determination after finding that risks were, in fact, high, and disregarded risk for 50% of the human population, including potentially exposed or susceptible populations.

4. EPA failed to consider real world exposures and risks for DIDP and DINP, leaving individuals and communities at serious risk of harm from exposures. For example, EPA failed to consider exposures from “non-TSCA” uses, including exposures through food packaging and personal care products. Given that food is the primary route of exposure to both DINP and DIDP in children and adults, EPA’s approach significantly understates the risk to the general population. EPA also failed to adequately identify and quantify risks to potentially exposed or susceptible subpopulations in both assessments, including residents of fenceline communities and individuals experiencing multiple chemical and non-chemical stressors.

What steps should EPA take moving forward?

EPA cannot continue down this dangerous path of underestimating, ignoring, and downplaying the risks of harmful chemical exposures. EPA should change its current approach by:

• Identifying health effects using the best available methods in systematic review to ensure that EPA’s decision-making is based on the most current science;

• Utilizing the best available methods (like the WHO method) to quantify non-cancer risk;

• Ensuring that all risk determinations are based on high-exposure estimates, which are more representative of real-world exposures, instead of downplaying or disregarding calculated risks;

• Accounting for “non-TSCA” or background exposures to DIDP and DINP, including sources like dietary exposures, which is the primary route of exposure to phthalates in humans; and

• Utilizing uncertainty factors to account for the full range of human responses to DIDP and DINP exposures.

We urge EPA to correct their oversights so that the Agency’s conclusions lead to better health protections for workers and other populations most at risk from DIDP and DINP chemical harms, including children, pregnant people, and low-income and communities of color already overburdened by chemicals and pollutants.

About the authors

Abena BakenRa, MPH is a Science Associate for the Science, Policy & Engagement team at PRHE. Through her research, Abena aims to address health effects in underserved and vulnerable communities, especially among historically oppressed groups. She received her MPH from University of California, Berkeley, specializing in Epidemiology and Biostatistics.

Rashmi Joglekar, PhD leads the Science, Policy & Engagement team at PRHE. She comes with a wealth of knowledge and understanding of how toxic chemicals impact susceptible populations and communities and is skilled in addressing these issues with decision-makers in Washington, DC. She completed her PhD in the Integrated Toxicology and Environmental Health Program at Duke University, specializing in neurodevelopmental toxicology.