Building more robust evaluation of health risks from chemicals and other stressors
The Toxic Substances Control Act (TSCA), the main U.S. chemical safety law, presents one of the most far-reaching opportunities to address the cumulative risks chemicals can pose to public health. TSCA, which was heavily reformed in 2016 with the passage of the Frank R. Lautenberg Chemical Safety for the 21st Century Act, is unique among U.S. environmental laws because it requires a holistic consideration of chemical risks. This includes an evaluation of all sources and pathways of exposure to the general population, as well as special consideration of those who may be at greater risk because they are more susceptible to a chemical’s effects or more highly exposed.
However, risk evaluations conducted by the U.S. Environmental Protection Agency (EPA) under TSCA have yet to live up to their regulatory potential. This ultimately leaves both the public at large, and the most vulnerable subpopulations in particular, at risk of adverse health effects.
Watch: Webinar on Improving TSCA risk assessment
EDF’s TSCA Cumulative Risk Assessment (CRA) Framework describes how the narrow risk evaluations conducted to date can scale up to yield a fully inclusive and comprehensive assessment of cumulative risk that matches the promise and requirements of TSCA. The CRA Framework illustrates how EPA can conceptualize and apply comprehensive cumulative risk evaluations in a way that is pragmatic and more protective of public health, especially for those at greatest risk.
Building towards a full evaluation of real-world risks
- Single-use risk: Limited evaluation of risk from specific uses of a single chemical and risk to selected vulnerable subpopulations
- Limited risk: Evaluation of risk from combined exposures to a single TSCA chemical and considering all vulnerable subpopulations.
- Aggregate risk: Expanded evaluation of risk from aggregate exposures to a single chemical accounting for background exposures from non-TSCA uses or other unidentified sources
- Cumulative risk: Complete evaluation of risk from exposure to multiple chemicals (or categories of chemicals) associated with the same health outcome(s)
- Cumulative impacts: Comprehensive evaluation of risk from both multiple chemicals and non-chemical stressors linked to the same health effects as the chemical undergoing risk evaluation
- Single-use risk: General population, workers on the job, pregnant women, and children
- Limited risk: General population, workers on the job, pregnant women, children, and frontline communities
- Aggregate risk: General population, workers on the job, pregnant women, children, frontline communities, and workers exposed to chemicals at home
- Cumulative risk: General population, workers on the job, pregnant women, children, frontline communities, workers exposed to chemicals at home, and persons with health conditions that are exacerbated by exposure to other chemicals
- Cumulative impacts: General population, workers on the job, pregnant women, children, frontline communities, workers exposed to chemicals at home, and persons with health conditions that are exacerbated by exposure to other chemicals and non-chemical stressors
- Single-use risk: Workers exposed to trichloroethylene during vapor degreasing operations
- Limited risk: Frontline communities that experience higher levels of exposure to 1,3-butadiene from rubber production facilities, including communities in Greater Houston and the Texas-Louisiana Gulf Region
- Aggregate risk: Workers exposed to formaldehyde in multiple ways, such as at their jobs in wood or paper manufacturing and at home from washing their hair with shampoo containing formaldehyde
- Cumulative risk: People with asthma who are exposed to multiple respiratory toxicants, such as particulate matter 2.5 (PM2.5) and formaldehyde, or Black women who are exposed to higher concentrations of multiple ortho-phthalates than other demographic groups
- Cumulative impacts: Combined effect of phthalate exposure and high stress during pregnancy, which is associated with preterm birth, among pregnant women experiencing discrimination and marginalization
1. Single-use risk
This level of risk evaluation assesses specific uses for a single chemical, excludes numerous sources of exposure to the chemical, fails to evaluate combinations of exposures, and does not consider all vulnerable subpopulations. It is incomplete and underestimates risk. Vulnerable subpopulations are any groups or communities that are more highly exposed to a chemical or susceptible to a chemical’s harmful effects. Under TSCA, EPA is required to consider how chemicals can affect these vulnerable subpopulations.
Since the 2016 reforms, however, EPA has taken a limited approach to chemical risk evaluations – such that all vulnerable subpopulations are not receiving appropriate consideration or protection.
2. Limited risk
Builds on Level 1. This risk evaluation considers all sources and pathways of exposure from single and combined uses of a specific chemical. It also considers all vulnerable subpopulations, as mandated under TSCA.
3. Aggregate risk
Builds on previous levels. This risk evaluation captures relevant, real-world, aggregate exposures from a single chemical. It also accounts for background exposures from non-TSCA uses or other unidentified sources that may overlap with other statutes and regulatory agencies, such as exposures to a chemical through food packaging or personal care products regulated by U.S. Food and Drug Administration.
The inclusion of background exposures in the risk evaluation captures relevant, real-world exposures to a chemical that inform the true extent of risk posed by an individual chemical being evaluated under TSCA.
4. Cumulative risk
Builds on previous levels and leverages EPA’s authority under TSCA to manage risks from multiple chemicals or categories of chemicals. This level of risk evaluation considers exposures to multiple chemicals and pollutants that are associated with the same health effects (e.g., neurodevelopmental or male reproductive effects) as the specific chemical undergoing risk evaluation.
5. Cumulative impacts
Builds on the previous level. This is a comprehensive evaluation of risk from both multiple chemicals and non-chemical stressors linked to the same health effects as the chemical undergoing risk evaluation. Non-chemical stressors include the detrimental effects associated with experiencing discrimination and marginalization, having limited financial resources and access to education and health care, and being subject to other social inequities. This is the most protective and realistic level of risk evaluation for individuals and communities.