Fourth Circuit Vacates PFAS Injunction Against Chemours, Clarifies Standing and Irreparable Harm in Clean Water Act Citizen Suits

On Wednesday, June 3, 2026, the U.S. Court of Appeals for the Fourth Circuit vacated a preliminary injunction that had restricted PFAS discharges from Chemours’ Washington Works facility in Parkersburg, West Virginia. While the court held that the environmental plaintiff had Article III standing to pursue injunctive relief, it ruled that the district court misapplied the irreparable‑harm standard and abused its discretion in granting a preliminary injunction.

The decision has significant implications for Clean Water Act (CWA) citizen suits, PFAS litigation, and how courts evaluate risk‑based health evidence at the preliminary‑injunction stage.

Background

• The Washington Works facility discharges wastewater containing HFPO‑DA (a PFAS compound sometimes associated with “GenX chemicals”) into the Ohio River under a state‑issued NPDES permit.
• The permit caps HFPO‑DA concentrations at the outfalls, with limits derived from a state goal of 140 parts per trillion (ppt) at the point of human exposure, accounting for treatment and dilution (opinion at pp. 6–7).
• EPA later adopted a Safe Drinking Water Act (SDWA) maximum contaminant level (MCL) and MCL goal (MCLG) of 10 ppt for HFPO‑DA, to be enforceable no earlier than April 2029 (p. 8).
• Chemours exceeded its permit limits on multiple occasions and entered into an administrative consent order with EPA in 2023; EPA conditionally approved PFAS abatement projects in 2025 (pp. 7–8).
• West Virginia Rivers Coalition sued under the CWA’s citizen‑suit provision and obtained a preliminary injunction ordering Chemours to comply immediately with permit limits and take “any measures necessary,” including production changes or temporary shutdowns (p. 9).
• Chemours appealed, challenging (1) the plaintiff’s standing and (2) the finding of irreparable harm.

Key Holdings

1. Article III Standing: Recreational “Avoidance” Injury Upheld

The Fourth Circuit held that the plaintiff organization, West Virginia Rivers Coalition, had associational standing based on one member’s testimony:

• The member had boated on the Ohio River in the past, regularly boats and kayaks elsewhere, and avoids boating on the affected reach of the Ohio River because of Chemours’ alleged violations.
• She testified she would boat there more often and with greater enjoyment if Chemours complied with its permit (pp. 11–14).

Relying on Supreme Court and Fourth Circuit precedent (Friends of the Earth v. Laidlaw; Gaston Copper), the court held:

• A plaintiff who reasonably curtails recreational use of a waterbody due to unlawful discharges suffers an injury‑in‑fact, even without proof that pollution reaches a specific numeric threshold on any particular day.
• No detailed “actual level of pollution” showing is required when there is a “direct nexus between the [plaintiff] and the area of environmental impairment” (p. 13).

Standing thus remains relatively accessible for environmental plaintiffs where there is a concrete recreational connection and documented permit violations.

2. Irreparable Harm: No Presumption, No Public Harm Shortcut

The court vacated the injunction because the plaintiff failed to show likely irreparable harm, emphasizing several core points:

• Irreparable harm must be to the plaintiff, not the public at large.
  • Winter v. NRDC requires that “he is likely to suffer irreparable harm” (emphasis in original).
  • Public harm is accounted for separately under the “public interest” factor; it cannot be double‑counted as irreparable harm (pp. 16–18).
• No automatic presumption of irreparable harm from a CWA violation.
  • Citing Weinberger v. Romero‑Barcelo and Amoco v. Gambell, the court rejected the district court’s rule that a “continuing violation of federal environmental law” gives rise to a presumption of irreparable harm (pp. 18–20).
  • Congress has expressly created presumptions of irreparable harm in other contexts (e.g., Lanham Act), but not for CWA citizen suits.
• Permit exceedances alone are not “irreparable harm.”
  • A permit violation triggers liability and may support enforcement, but it is not itself irreparable harm to the plaintiff (p. 20).

3. Risk vs. Likelihood: Expert Testimony Insufficient

The district court relied on the plaintiff’s toxicology expert, who tied irreparable harm to any exposure above the 10‑ppt SDWA MCLG for HFPO‑DA. The Fourth Circuit found this insufficient for two reasons:

• “Increased risk” is not enough.
  The expert ultimately conceded that a single day’s exposure above 10 ppt increased the risk of adverse health effects but did not make harm “likely” or “more likely than not” (pp. 22–23).
  • Under Winter, irreparable harm must be likely, not merely possible.
• Failure to connect risk to this plaintiff’s actual exposure.
  • The record showed the member no longer drinks or cooks with her tap water, using it only for brushing teeth, bathing, cleaning, and watering plants (p. 23).
  • When asked whether such limited exposure would cause harm, the expert testified she could not reach a conclusion without more information on the extent of those uses (pp. 23–24).
  • Despite this, the district court found irreparable harm for “each incremental exposure.”

The appellate court held that relying on testimony that at most described an unquantified increase in risk—and expressly disclaimed an opinion tied to the member’s actual exposure—was clearly erroneous under the deferential standard of review (pp. 24–25).

Practical Implications

For Regulated Facilities and Permit Holders

• Citizen suits remain viable even where EPA or states are already pursuing administrative remedies; an administrative consent order does not itself bar CWA citizen actions.
• Standing remains broad in the Fourth Circuit: reasonable avoidance of recreation due to permit violations can support standing without extensive scientific proof of exposure levels.
• Irreparable harm is a meaningful constraint on preliminary injunctive relief:
  • Plaintiffs must tie health‑risk evidence to the probability of harm to specific individuals, not just statistical or theoretical risk.
  • Facilities facing PFAS or other risk‑based claims may successfully oppose preliminary injunctions where plaintiffs cannot show a likely (more‑than‑50%) personal harm under realistic exposure scenarios.

For Environmental and Community Groups

• The decision confirms that recreational and use‑based injuries are sufficient for standing where members credibly avoid using a waterbody because of unlawful discharges.
• But obtaining early injunctive relief will require:
  • Robust, exposure‑specific expert analysis that addresses how members actually use water (drinking vs. incidental contact).
  • Evidence that projected health effects are probable, not just possible or increased risk.

For PFAS and SDWA–CWA Interplay

• The court accepted that the 10‑ppt HFPO‑DA MCL/MCLG, though not yet enforceable for SDWA liability, is relevant to:
  • Standing (injury‑in‑fact) and
  • Assessing whether discharges and exposures create cognizable harm (pp. 8, 21–22).
• However, using a future SDWA standard as a health benchmark does not automatically satisfy Winter’s “likely irreparable harm” requirement—plaintiffs must still bridge the gap between regulatory benchmarks and individualized risk.

Key Takeaways

• No automatic injunction for CWA violations. Courts must still apply the full Winter test, including a rigorous irreparable‑harm analysis tailored to actual plaintiffs.
• Standing and irreparable harm are distinct. Recreational avoidance can establish standing, but early injunctive relief requires proof of likely—not just possible—harm.
• PFAS litigation will turn on exposure detail. How plaintiffs actually use water (drinking vs. non‑ingestion uses) and how experts quantify risk will be decisive at the preliminary‑injunction stage.
• Regulated entities should document compliance efforts. The existence of an EPA consent order and approved abatement plans featured prominently in the factual background and may influence equitable analysis, even though they did not bar the citizen suit.

This client alert is for general informational purposes only and does not constitute legal advice. For questions, readers should contact Michael Blumenthal, David Waxman, or a member of Frantz Ward’s Environmental Practice Group.