In a Clean Water Act (CWA) citizen suit, the district (trial level) judge issued a preliminary injunction against a chemical company; the injunction ordered the company to cease releasing more hexafluoropropylene oxide dimer acid (HFPO-DA) than allowed under its CWA permit. HFPO-DA is part of the large chemical class of per- and polyfluoroalkyl substances (PFAS).

Factors for Preliminary Injunctions
Courts use preliminary injunctions to regulate a party’s actions while the case is pending. To issue them, courts require a clear showing 1) of the likelihood of success on the merits, 2) of the necessity of the preliminary injunction to avoid irreparable harm, 3) that the balance of equities tips in favor of the injunction, and 4) that an injunction is in the public interest.

The chemical company filed an appeal to the US Court of Appeals for the Fourth Circuit, arguing that the district court improperly found irreparable harm. The 4th Circuit agreed with the company and reversed the injunction.

Evidence Insufficient to Show Irreparable Harm
The 4th Circuit concluded that the district court’s determination of irreparable harm to the public was insufficient. Rather, the organization that brought the suit had to show irreparable harm to its individual member who established the organization’s standing. While finding irreparable harm to the member might have established irreparable harm to the public, establishing irreparable harm only to the public cannot establish harm to any individual.

The 4th Circuit said the district court was wrong to presume irreparable harm, noting that the United States Supreme Court has held that such a presumption should be made only when the statute expressly demands it, which the CWA does not do.

Finally, the environmental organization’s expert could not quantify the member’s likely future exposure to HFPO-DA, thus preventing a determination of irreparable harm to that member.

To see the court’s opinion https://www.ca4.uscourts.gov/opinions/251924.P.pdf