Microplastics and per- and polyfluoroalkyl substances, or PFAS, are showing up in regular conversations about drinking water, regulation, and business risk.
Last month, the Environmental Protection Agency released the draft Sixth Contaminant Candidate List, or CCL 6. The list includes 88 unregulated contaminants the EPA is considering for possible future drinking water regulation: 75 individual chemicals, four broader chemical groups, and nine microbial contaminants. The four chemical groups are microplastics, PFAS, disinfection byproducts, and pharmaceuticals.
It isn’t a proposed rule, so it doesn’t create any immediate obligations. And not every contaminant on the list will necessarily end up being regulated. Before the EPA can move forward with a formal rule, Section 1412(b)(1)(A) of the Safe Drinking Water Act requires the agency to find that:
- A contaminant may pose a risk to human health
- The contaminant is known or likely to show up in drinking water at concerning levels
- Regulation would actually help reduce that risk
But companies should still pay attention, because the draft list points to where EPA focus could shift next. Possible actionable steps include requesting more information from suppliers, reviewing contracts and internal controls, and submitting comments on CCL 6 by June 5.
Main Emerging Contaminants
At a high level, all items on the draft list can be understood as emerging contaminants. They aren’t regulated under national drinking water standards yet, but they’re important enough to monitor. Microplastics and PFAS are drawing the most immediate attention.
Microplastics are tiny plastic fragments, fibers, and particles (generally smaller than five millimeters) that may enter drinking water through the breakdown of plastic products, synthetic textiles, personal care products, and industrial activity.
This is the first time microplastics are appearing on the EPA’s candidate list for drinking water, and the agency appears to be deciding some basic questions: what characteristics matter, how they should be measured, and from where they are coming.
PFAS, known as “forever chemicals” for their persistence in the environment, is further along. PFAS are synthetic compounds designed to resist heat, water, and stains and have been widely used in food packaging, cookware, cosmetics, clothing, carpeting, coatings, and firefighting foam. PFAS appeared on the EPA’s draft CCL 5 and returns on CCL 6—with a narrower focus on compounds not already regulated.
The real issue now is where this watch list is most likely to affect businesses first. That starts with three practical questions:
Where do microplastics and PFAS create exposure? Some businesses already know where these substances could appear. For others, the answer is less obvious. Microplastics or PFAS may enter through raw materials, manufacturing equipment, packaging, supplier practices, wastewater discharges, or products purchased from third parties.
This means companies should consider mapping where these substances could arise across their businesses—not only in finished products, but also in manufacturing processes, waste streams, and supplier relationships.
Companies also may want to ask suppliers whether they use PFAS-containing materials or whether their products may generate or contain microplastics. This exercise could be especially important, as some of the greatest exposures may sit elsewhere in the supply chain.
Businesses operating in California have even less reason to wait. The state already requires large public water systems to test for and disclose microplastics data, which may preview what could happen more broadly across the country.
Are testing, reporting, and defensibility systems in place? This question comes next for a reason: Once a company knows where microplastics or PFAS might enter the business, the practical follow-up is whether it could identify, measure, and respond to them if regulators asked tomorrow.
For many companies, the answer still may be no. That matters because the EPA also noted there is no widely accepted method for detecting and measuring microplastics in drinking water, while PFAS regulation is moving quickly and testing demands may continue to expand.
If a business can’t reliably detect or report these substances, the next question is whether its contracts and internal controls are built to absorb that gap. Companies may want to review product specifications, indemnities, insurance provisions, supplier agreements, and disclosure obligations.
The same issue may arise with marketing claims. “PFAS-free,” “plastic-free,” or “microplastic-free” statements may become more important as regulators and consumers pay closer attention. But they can also create risk if companies can’t substantiate them.
Why does the comment period matter, and how can businesses use it? The EPA’s draft CCL 6 now gives companies a concrete next step: Submit comments by June 5 if they want to help shape what the agency is considering.
For microplastics, the EPA still appears to be working through what should count as microplastic, how it should be measured, and which exposure pathways matter most. Companies in plastics, packaging, textiles, water treatment, consumer products, and manufacturing have a clear opportunity to help shape those definitions.
PFAS presents a slightly different set of issues. Companies should consider commenting on whether the EPA’s structural definition is too broad or narrow, which compounds should take priority, and how already regulated PFAS should be treated.
Across both topics, the most useful comments are likely to be practical ones discussing limits on testing, supply-chain impacts, implementation challenges, costs, and unintended consequences the EPA may not yet have fully considered.
Bottom Line
CCL 6 is an early warning, not a headline to skim past. The EPA is telling companies where scrutiny may intensify next, and businesses that treat that signal seriously now will have a better chance of avoiding rushed disclosures, awkward surprises, and reactive cleanup later.
This article does not necessarily reflect the opinion of Bloomberg Industry Group, Inc., the publisher of Bloomberg Law, Bloomberg Tax, and Bloomberg Government, or its owners.
Author Information
Ayodeji Ayolola is senior counsel at Gordon Rees Scully Mansukhani, representing businesses in toxic tort matters involving alleged exposure and contamination.
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