Cumulative Impacts Research

In everyday life, some people are exposed to numerous pollutants from a wide array of sources through multiple media and pathways. Chemical stressors in environmental media (air, water, land) and non-chemical stressors (e.g., social determinants of health, extreme weather events) aggregate and accumulate over time from one or more sources in the built, natural, and social environments, affecting individuals and communities in both positive and negative ways―referred to as cumulative impacts. In communities, particularly those already overburdened, disproportionate impacts can arise from unequal environmental conditions and exposure to multiple stressors. Additionally, changes in climate can exacerbate many of these disproportionate impacts.

Agency Directive

In January 2021, President Biden signed Executive Orders (EO) 13985 and 14008 to advance racial equity and support for underserved communities and to address the climate crisis. These EOs provide a framework for stimulating action across the federal government to address health inequities in the U.S. caused by disproportionate exposures to pollution and environmental degradation that are exacerbated by racial, economic, and geographic factors and climate change. 

In support of these Orders, EPA Administrator Regan issued an Agency-wide directive to take steps to better serve historically marginalized communities using cumulative impact assessment.

To fulfill its mission to protect human health and the environment, EPA must address cumulative impacts from exposure to multiple stressors. To do this, the Agency must strengthen the scientific foundation for assessing cumulative impacts, exposures, and risks. Recognizing the need to bolster the scientific basis for identifying actions that can improve community health and well-being, and to select, implement, and evaluate these actions, EPA has made cumulative impacts research a priority.

How EPA’s Research is Addressing Cumulative Impacts

Solving longstanding environmental health problems, including health disparities exacerbated by racial and social injustices, requires an accurate and realistic assessment of the effects from combined exposures to chemical and non-chemical stressors (cumulative impacts) that inform decision-making at all levels.

EPA’s Office of Research and Development (ORD) aims to support federal, tribal, state, and community decision-making by strengthening the scientific foundation for assessing cumulative impacts, exposures, and risks through existing and new methods, tools, data, and monitoring. Cumulative impacts research is a priority to bolster the scientific basis for identifying actions that can improve community health and well-being.

Over the past year, ORD developed fiscal years 2023-2026 Strategic Research Action Plans (StRAPs) for each of its six National Research Programs. The StRAPs integrate efforts to improve our understanding of cumulative impacts to support real-world assessments of both adverse and beneficial health and environmental effects.

Cumulative Impacts Research Report

ORD published the final report, Cumulative Impacts Research: Recommendations for EPA’s Office of Research and Development, to inform the FY23-26 StRAPs. This report focuses on recommendations to enhance cumulative impact research that are applicable across the National Research Programs and includes recommendations for how ORD can provide management support to facilitate this complex research.

This report represents ORD’s commitment to develop an integrated cumulative impact research portfolio, in collaboration with others, to inform decision-making at all levels.

• The recommendations in the report are already informing actions within ORD to advance the state of the science, and we are prepared to do more as we implement cumulative impacts research in the years to come.
• Building on the broad input we received from partners and stakeholders, the report presents recommendations that will assist ORD with integrating research efforts to improve our understanding of cumulative impacts and conduct real-world assessments.
• Both cumulative impacts and cumulative impact assessment are defined in the interest of providing clarity and consistency across ORD’s research portfolio.
• Research gaps and barriers to implementing cumulative impact research at EPA are identified and recommendations are made for advancing this research as an explicit part of each of ORD’s six FY23-26 StRAPs.
• Recommendations are included for cumulative impacts research that will provide data and information the Agency needs to meet its commitment to advancing environmental justice.
• Recommendations are provided for cumulative impact assessments that will address the unique vulnerabilities of children and vulnerable populations.

This report was prepared by an interdisciplinary group of scientists and experts from EPA’s ORD, Office of Environmental Justice, and regional offices, and is based on input from EPA programs and regions; states, tribes, and community representatives; the EPA Science Advisory Board; public comments; and previous recommendations from the National Environmental Justice Advisory Committee and the White House Environmental Justice Advisory Committee.

Science Matters article: EPA Researchers Release Cumulative Impacts Report, Prioritizing Environmental Justice in New Research Cycle

Additional Resources

• ORD Strategic Research Action Plans
• FY 2023–FY 2026 EPA Strategic Plan
• Science Advisory Board (SAB) - The Chartered SAB consulted with EPA on research needed to improve the state of the science supporting cumulative impact assessments as part of public meetings.