EPA Adds Microplastics to Drinking Water Contaminant Study List

The Environmental Protection Agency proposed on April 2, 2026, to add microplastics and pharmaceuticals to its Contaminant Candidate List for the first time, opening a 60-day comment period before expected finalization in mid-November 2026. The move comes as Health Secretary Robert F. Kennedy Jr. announced a $144 million STOMP initiative to measure and remove microplastics from human bodies, and EPA Administrator Lee Zeldin explicitly framed the proposal as appealing to Kennedy's MAHA movement. However, environmental advocates like the Natural Resources Defense Council remain skeptical, noting the EPA rarely moves contaminants from the list to actual regulation and recently announced it would not regulate any of nine pollutants from its most recent review. The designation occurs amid political tensions, with MAHA activists frustrated by lack of action on pesticides while President Trump issued an executive order boosting glyphosate production earlier in 2026.

EPA's Proposal to Add Microplastics and Pharmaceuticals to Contaminant List

• ▪The new draft Contaminant Candidate List includes four contaminant groups: microplastics, pharmaceuticals, PFAS, and disinfection byproducts, as well as 75 chemicals and nine microbes.
• ▪The EPA's Contaminant Candidate List identifies contaminants in drinking water not regulated under the Safe Drinking Water Act.
• ▪The EPA is publishing the draft of the sixth version of the Contaminant Candidate List, which opens a 60-day public comment period.
• ▪The Environmental Protection Agency proposed on Thursday, April 2, 2026, to include microplastics and pharmaceuticals on the Contaminant Candidate List for drinking water contaminants for the first time.
• ▪The EPA expects to finalize the sixth version of the Contaminant Candidate List by mid-November 2026.
• ▪The Safe Drinking Water Act, as amended in 1996, directed the EPA to publish the Contaminant Candidate List every five years.

Health Concerns and Scientific Research on Microplastics

• ▪Health Secretary Robert F. Kennedy Jr. announced a $144 million effort called STOMP (Systematic Targeting of Microplastics) to measure, understand, and remove microplastics from human bodies.

Political Context: MAHA Movement and Kennedy-Zeldin Collaboration

• ▪EPA Administrator Lee Zeldin said the microplastics and pharmaceuticals proposal aims to hand a win to Health Secretary Robert F. Kennedy Jr.'s MAHA movement.
• ▪In February 2026, EPA press secretary Brigit Hirsch told The Associated Press that the MAHA agenda was in its final stages.
• ▪Health Secretary Robert F. Kennedy Jr.'s MAHA movement has for months pressured EPA Administrator Lee Zeldin to further crack down on environmental contaminants.
• ▪Robert F. Kennedy Jr. ran an independent presidential campaign in 2024 that focused in part on tackling plastic pollution.
• ▪President Trump issued an executive order earlier in 2026 aimed in part at boosting the production of glyphosate, a controversial herbicide ingredient.
• ▪Health Secretary Robert F. Kennedy Jr. said he was disappointed by President Trump's glyphosate executive order but sees it as necessary for agricultural stability and national security.

Historical Limitations and Skepticism About Regulatory Action

• ▪The Natural Resources Defense Council and other environmental advocates are fighting to keep the entire Biden-era forever chemicals rule in place.
• ▪In five cycles of the Contaminant Candidate List process, the EPA has determined that no regulatory action is appropriate or necessary for most of the contaminants it considered.
• ▪The EPA said in March 2026 that it will not develop regulations for any of the nine pollutants from the Contaminant Candidate List it most recently examined.
• ▪The EPA rarely moves pollutants off the Contaminant Candidate List to set limits for how much is allowed in public drinking water.
• ▪In May 2026, the EPA announced plans to rescind limits on some less common forever chemicals in drinking water, roughly a year after the Biden administration finalized the first-ever national standards.
• ▪Erik Olson, a senior attorney at the Natural Resources Defense Council, said the Contaminant Candidate List process is the beginning of a very long process that routinely ends in nothing.
• ▪The Safe Drinking Water Act requires the EPA to determine whether to regulate at least five contaminants from the Contaminant Candidate List after each publication.

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