What the EPA’s GHG Rescission Means for Vehicle Emissions Testing Requirements

Troy, Michigan — July 2026 — Following the EPA’s February ruling on greenhouse gas standards, manufacturers face shifting regulatory landscapes. While federal GHG reporting requirements have been reduced, the need for emissions testing remains robust.

Criteria pollutants—regulated since the 1970s—remain mandatory compliance areas. Requirements for carbon monoxide, nitrogen oxides, total hydrocarbons, NMOG, and particulate matter continue to demand rigorous testing. “CO2 measurement plays a critical role in determining vehicle exhaust volume,” which is essential for calculating mass-based emissions under CFR testing procedures.

Despite reduced GHG reporting, manufacturers must still measure CO2, N2O, and CH4. The rescission does not eliminate measurement requirements; instead, it reshapes compliance priorities.

Organizations should maintain CFR Part 1065/1066-compliant testing, expand support for state-level CARB requirements, integrate emissions testing into broader validation programs, and leverage independent laboratories for pre-compliance work. As the article notes, “independent testing laboratories become even more critical” in providing objective data, supporting flexible testing programs, and accelerating time-to-market across multiple regulatory pathways.

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