EPA Rolls Back National Park Pollution Rules Amid Lawsuits

The United States Environmental Protection Agency is rolling back pollution restrictions under the regional haze rule, which governs air quality across 150 national parks and wilderness areas. Following a March 2025 announcement by Administrator Lee Zeldin to roll back 31 environmental regulations, the agency shifted its policy to approve state pollution plans based on visibility benchmarks rather than requiring technology evaluations at polluting plants.

This policy shift led the agency to approve plans for West Virginia and California that were previously rejected. Conversely, the EPA rejected Colorado's air quality plan in January 2026 and signaled a likely rejection of Hawaii's plan in February 2026. The agency argues that these states mandated coal plant or boiler closures that could jeopardize grid reliability and violate legal property rights.

The National Parks Conservation Association, the Sierra Club, and Earthjustice have filed lawsuits against the EPA. These organizations allege that the regulatory reversals allow polluting facilities to remain online and threaten air quality in parks such as Shenandoah and Mammoth Cave.