Quick Facts

• EPA’s draft Sixth Contaminant Candidate List includes microplastics and pharmaceuticals as drinking water threats for the first time
• HHS launches $144 million STOMP program to develop tools for measuring and removing microplastics from human bodies
• Research shows 93% of bottled water contains microplastics, with plastic concentration in human brains rising 50% since 2016

The Environmental Protection Agency flagged microplastics and pharmaceuticals as potential drinking water contaminants for the first time in its draft Sixth Contaminant Candidate List (CCL 6) released April 2, 2026.

EPA Administrator Lee Zeldin announced the list includes four contaminant groups—microplastics, pharmaceuticals, PFAS, and disinfection byproducts—plus 75 chemicals and nine microbes that may appear in drinking water systems.

“For too long, Americans have vocalized concerns about plastics and pharmaceuticals in their drinking water. That ends today,” Zeldin said. “By placing microplastics and pharmaceuticals on the Contaminant Candidate List for the first time ever, EPA is sending a clear message: we will follow the science.”

The Department of Health and Human Services simultaneously launched STOMP: Systematic Targeting Of MicroPlastics, a $144 million program to develop tools for measuring and removing microplastics from human bodies.

HHS Secretary Robert F. Kennedy Jr. warned that researchers have found plastic particles in human blood, lung tissue, livers, kidneys and every tested human placenta sample. The concentration of plastics in human brains has jumped 50% since 2016.

“We are not dealing with a distant or theoretical risk. We are dealing with a measurable and growing presence inside the human body,” Kennedy said.

A clinical study found patients with microplastics in arterial plaque faced a 450% higher risk of heart attack, stroke or death within three years. Research shows tap water leads to an estimated 4,000 microplastic particles consumed annually, while bottled water adds approximately 90,000 particles per year.

Analysis of 259 bottled water products across nine countries found 93% contained microplastics.

The EPA also released human health benchmarks for 374 pharmaceuticals, giving water systems tools to assess risk when drug residues appear at concerning levels. Pharmaceutical contamination occurs because humans excrete medications and conventional wastewater treatment plants fail to remove them completely.

The draft list enters a 60-day public comment period. EPA will consult its Science Advisory Board before finalizing the list by November 17, 2026.

Inclusion on the candidate list allows local regulators to evaluate risks and can trigger research and regulatory action, but does not guarantee new regulations will follow. The EPA said in March it will not develop regulations for any of the nine pollutants from its most recent examination.

ARPA-H Director Dr. Alicia Jackson said the STOMP program will develop a clinical test for microplastics that takes less than 15 minutes and costs under $50.

“Microplastics are in every organ we look at—in ourselves and in our children. But we don’t know which ones are harmful or how to remove them,” Jackson said.

Environmental advocates called the announcement an important first step but noted the regulatory process typically takes a decade or longer to produce new drinking water standards.

Read more: EPA flags microplastics, pharmaceuticals as contaminants in drinking water