NOTE: This is the second part of a series on EPA’s prioritization of existing chemicals.
What happened?
EPA just suggested to classify five chemicals, including the widely known toxic vinyl chloride, as high priority chemicals – that is, they are toxic to human health and/or the environment. If this decision is taken, these chemicals will immediately be subjected to the risk assessment process under the Toxic Substances Control Act (TSCA).
When EPA designates these chemicals as high priority chemicals and further assesses their health risks, it can – and should – consider exposure to multiple chemicals that can cause the same health effects. To illustrate the importance of these cumulative exposures, we conducted an analysis of simultaneous exposure to these five chemicals and submitted this analysis to the EPA to better consider the actual risks to people exposed to these toxic chemicals.
Why it is important
Communities near industrial facilities are often exposed to multiple chemicals that cause the same health effects. Assessing the health risk of these chemicals individually, as is currently done in EPA’s TSCA program, often underestimates the true risks communities face. In addition, many of these border communities face a number of non-chemical stressors that exacerbate the health effects of chemical exposure, such as physiological stress from poverty and racial discrimination, limited access to health care, or health effects from climate stressors such as flooding and heat. Failure to consider these cumulative health stressors in chemical risk assessments often underestimates the true risks these chemicals may pose to human health.
Our opinion
Our analysis of Toxics Release Inventory (TRI) data from 2016 to 2021 shows that many chemicals that cause the same health effects – such as cancer, central nervous system (neurological) effects, cardiovascular disease, liver, kidney and thyroid, and reproductive and developmental effects – are often released together from the same facilities. For example, chemicals that cause cardiovascular disease are released together with at least one other chemical that causes the same effects 74% of the time.
The five chemicals just proposed as high priority under TSCA are known or probable carcinogens, with some of them also causing other adverse health effects. Based on our analysis, there are some notable joint releases that EPA should consider when assessing cumulative risk with other chemicals that cause the same harms. For example, creosote, which is also a probable carcinogen and can cause liver, kidney, and thyroid damage, is released 11% of the time with acrylonitrile, 18% with aniline, 11% with vinyl chloride, and 11% with 4,4-methylenebis(2-chloroaniline).
Heat map of joint releases of cancer-causing chemicals that are part of the TSCA work plan. Legend shows the percentage of facilities releasing both chemicals compared to facilities releasing at least one of the two chemicals. Stars represent the 15 chemicals considered as part of the TSCA pre-prioritization.
To demonstrate that EPA should also consider non-chemical stressors such as climate and environmental justice in its TSCA prioritization and risk assessment, we examined the vulnerability of communities to climate and environmental justice factors in areas where certain chemicals are released using EDFs. Climate Vulnerability IndexOn average, vinyl chloride is released into communities at higher risk than other chemicals analyzed – up to 12% more than the average for other carcinogenic chemicals.
What’s next?
EPA is now accepting comments on its proposal to designate these five chemicals as high priority chemicals, and we plan to submit comments in support of the designation as high priority chemicals. When the proposal is finalized, EPA will begin risk assessment of these chemicals. We hope that EPA will consider cumulative risk and environmental justice as this process progresses.
In our next post in this series, we provide recommendations on how EPA can improve its prioritization process by considering the risks associated with the transportation and distribution of chemicals.
