Fifth Circuit Extends Pause In 1,4-Dioxane Suit Amid Government Shutdown

The U.S. Court of Appeals for the Fifth Circuit has granted the U.S. Environmental Protection Agency (EPA) another 90-day extension in its litigation over the Biden administration's revised evaluation of 1,4-dioxane (1,4-DX) under the Toxic Substances Control Act (TSCA). This pause, requested by EPA, is intended to allow continued review of the chemical's cancer risk assessment. Union Carbide Corp. v. EPA, No. 24-60615 (5th Cir., filed September 30, 2025).

In 2020, during the final days of the first Trump administration, EPA concluded that 1,4-DX poses unreasonable risk to workers in 13 of 24 evaluated conditions of use. But the 2020 evaluation also concluded that the chemical poses no unreasonable risk as a byproduct in consumer products. In a 2024 evaluation, the Biden EPA reversed course, concluding that 1,4-DX poses unreasonable risk across its uses, including byproduct exposures previously deemed safe. Industry groups challenged the revised assessment,