For the first time, the U.S. Environmental Protection Agency (USEPA) is including microplastics as a priority contaminant group. The draft Sixth Contaminant Candidate List (CCL 6) is now open for public comment. The CCL 6 also includes pharmaceuticals as a group for the first time, as well as per- and polyfluoroalkyl substances (PFAS), disinfection byproducts, 75 individual chemicals, and nine microbes that may be present in public drinking water systems.
The CCL is published every five years under the Safe Drinking Water Act and guides USEPA research priorities, funding decisions, and regulatory agenda for substances not yet subject to national primary drinking water standards. Inclusion on the CCL does not constitute regulation, but signals that a substance warrants serious scientific attention and may be considered for future regulatory action.
Additionally, the Advanced Research Projects Agency for Health (ARPA-H) announced the launch of the Systematic Targeting of Microplastics (STOMP), a first-of-its-kind nationwide initiative to build a comprehensive toolbox for measuring, researching, and removing microplastics and nanoplastics (MNPs) from the human body.
STOMP consists of a three-pronged approach:
- Measure: Deploy detection technology to accurately quantify microplastics levels in water and human tissue.
- Target: Identify the most harmful plastic contaminants and determine how they enter and move through the body.
- Remove: Develop and validate methods to eliminate microplastics from the human body.
Together, the CCL 6 and STOMP initiatives represent the most comprehensive Federal effort to date to understand and combat the risks posed by microplastics to public health.
USEPA is accepting public comments via the Federal Register through June 5, 2026. Learn more about CCL 6 and STOMP on the USEPA and Health and Human Services websites.