In Berkey International, LLC v. Environmental Protection Agency, No. 24-1917 (1st Cir. September 18, 2026), a Puerto Rico limited liability company, Berkey International, LLC, manufactured water filters known as Black Berkey Filters, which contained silver —a substance recognized as a pesticide. Berkey distributed these filters without EPA registration, claiming the silver was intended only to protect the filters themselves, not for pesticidal purposes. Inspections by the Environmental Protection Agency (EPA) revealed that Berkey and associated distributors made claims on product labels and websites indicating the filters could remove viruses, bacteria, and other pathogens, suggesting pesticidal intent. As a result, the EPA issued a Stop Sale, Use, or Removal Order prohibiting Berkey and other distributors from selling or distributing these filters.
Reviewing the matter, the United States District Court for the District of Puerto Rico considered Berkey’s request for a preliminary injunction to halt enforcement of the EPA’s order. The district court evaluated the administrative record, held hearings, and reviewed extensive briefing. The court found that Berkey had not substantiated its claims that the silver was not intended for pesticidal use and denied Berkey’s motion for preliminary injunctive relief. Berkey’s subsequent motion for reconsideration was also denied, prompting Berkey to file an interlocutory appeal.
The United States Court of Appeals for the First Circuit reviewed the district court’s denial of preliminary injunctive relief for abuse of discretion. Applying a highly deferential standard to the EPA’s technical determinations, the appellate court concluded that Berkey had not shown a likelihood of success on the merits of its claims under the Administrative Procedure Act, including its assertions of arbitrary and capricious agency action and violations of notice-and-comment and due process requirements. The First Circuit affirmed the district court’s order, holding that the EPA had reason to believe Berkey’s filters were unregistered and misbranded pesticidal products under federal law.