On July 6, 2026, Environmental Protection Network submitted formal comments opposing EPA’s proposed rule to delay the phase-in schedule for Tier 4 vehicle emission standards, arguing that the rollback is based on speculative assertions rather than objective data. EPN contended that the proposal ignores the agency’s own in-house certification data, violates fundamental administrative law principles under the Clean Air Act, and relies on an unlawful “fig-leaf” theory that undermines rigorous, fact-based environmental regulation.
Revision of Tier 4 Criteria Pollutant Standards, Part 1: Amendments to Phase-In Schedule for Light-Duty and Medium-Duty Vehicles
