EPA Sends 4 More California Vehicle Emission Waivers To Congress For Potential Nullification

Highlights

• The U.S. Environmental Protection Agency (EPA) recently announced that it was submitting four waivers issued to California under the Clean Air Act to the U.S. Congress for review under the Congressional Review Act.
• Section 209 of the Clean Air Act expressly preempts states from regulating motor vehicle emission standards with the exception of California, which may request a "preemption waiver" from EPA.
• Now that the waivers have been submitted, Congress has 60 days of continuous session (which excludes days that either or both houses of Congress is adjourned for more than three days pursuant to an adjournment resolution) to pass a disapproval resolution invalidating them.

The U.S. Environmental Protection Agency (EPA) announced on June 12, 2026, that it was submitting four additional waivers issued to California under the Clean Air Act to the U.S. Congress for review under the Congressional Review Act (CRA). This follows the three waivers disapproved by Congress under the CRA in May 2025.

Section 209 of the Clean Air Act¹ expressly preempts states from regulating motor vehicle emission standards with the exception of California, which may request a "preemption waiver" from EPA. When EPA issues a waiver to California, Section 177 of the Clean Air Act² also allows other states to adopt the same emission standards for which California has received a waiver. Since the passage of the Clean Air Act in the 1970s, California has received numerous waivers from EPA to set its own vehicle emission standards, and many states have adopted these vehicle standards.

The Waivers at Issue

The waivers at issue in this transmittal to Congress are for:

• California's greenhouse gas (GHG) emission standards for 2009 and subsequent model year passenger cars, light-duty trucks and medium-duty vehicles³
• the Advanced Clean Cars I (ACC I) program,⁴ which addresses criteria pollutant and GHG emissions for light-duty vehicles starting with model year 2015
• the Biden Administration's 2022 reinstatement of the ACC I waiver,⁵ which had been rescinded during the first Trump Administration
• the Small Off-Road Engine (SORE) amendments,⁶ which set exhaust standards for lawn and garden equipment but cannot be adopted by other states

Expansion of CRA Strategy and Legal Uncertainty Over Applicability

The Trump Administration and Congress have taken aim at California's Section 209 waivers before. As described in a previous Holland & Knight alert, in 2025, Congress used its authority under the CRA to disapprove multiple waivers issued to California by the Biden Administration, including for California's Advanced Clean Cars II program, and President Donald Trump signed the disapprovals in June 2025.

The use of the CRA against these waivers has been the subject of legal debate. Historically, EPA had not submitted Section 209 determinations to Congress as "rules" under the CRA.⁷ Prior to Congress considering the 2025 disapprovals, the U.S. Government Accountability Office and U.S. Senate Parliamentarian had asserted that the waivers did not qualify as "rules" subject to the CRA.⁸ Congress proceeded with the disapproval resolutions over those objections, and President Trump signed them into law. California and a coalition of states subsequently filed suit,⁹ challenging EPA's submission of the waivers to Congress and the validity of the congressional disapprovals. As of this writing, that litigation is ongoing.

The new CRA submissions extend this strategy in a notable direction. Unlike the June 2025 CRA actions – which targeted relatively recent waivers granted by the Biden Administration – these submissions include waivers dating as far back as 2009. They also encompass the SORE amendments governing lawn and gardening equipment, which are categories that were not previously subject to CRA review. On June 22, 2026, California filed a separate lawsuit seeking declaratory and injunctive relief against EPA's actions, this time in federal district court in Washington, D.C.¹⁰

These developments are unfolding against the backdrop of a period of significant volatility for mobile source regulation more broadly. The submission of the ACC I waiver to Congress is occurring in parallel with a lawsuit filed by the U.S. Department of Justice in March 2026 seeking to permanently enjoin California's ACC I program on the grounds that it is preempted by the Energy Policy and Conservation Act.¹¹ At the federal level, the status of GHG emission standards for light-, medium- and heavy-duty vehicles is itself in flux following EPA's February 2026 final rule repealing those standards alone with the 2009 Endangerment Finding that formed their legal predicate.¹²

Next Steps

Now that the waivers have been submitted, Congress has 60 days of continuous session (which excludes days that either or both houses of Congress is adjourned for more than three days pursuant to an adjournment resolution) to pass a disapproval resolution invalidating them.

Footnotes

1. 42 U.S.C. § 7543.

2. 42 U.S.C. § 7507.

3. 74 Fed. Reg. 32744 (July 8, 2009).

4. 78 Fed. Reg. 2112 (Jan. 9, 2013).

5. 87 Fed. Reg. 14332 (March 14, 2022)

6. 90 Fed. Reg. 640 (Jan. 6, 2025).

7. See, e.g., 69 Fed. Reg. 59920, 59922 (Oct. 6, 2004).

8. Rachel Frazin, "Senate Parliamentarian Says Lawmakers Can't Overturn California Car Rules – But Republicans May Try Anyway," The Hill (April 4, 2025); U.S. Gov't Accountability Off., B-337179, "Observations Regarding the Environmental Protection Agency's Submission of Notices of Decision on Clean Air Act Preemption Waivers as Rules Under the Congressional Review Act" (March 6, 2025); U.S. Gov't Accountability Off., B-334309, "Environmental Protection Agency – Applicability of the Congressional Review Act to Notice of Decision on Clean Air Act Waiver of Preemption" (Nov. 30, 2023).

9. California v. United States, Case No. 4:25-cv-04966-HSG (N.D. Cal.).

10. California v. EPA, Case No. 1:26-cv-2815 (D.D.C.).

11. United States v. CARB, Case No. 2:26-cv-450 (E.D. Cal.).

12. 91 Fed. Reg. 7686 (Feb. 18, 2026).