Laws and rules

United States Code

Section 202 of the Clean Air Act (42 U.S.C. § 7521) authorizes EPA to prescribe emission standards for new motor vehicles and new motor vehicle engines.

United States Code

Federal law prohibits removing or rendering inoperative any emission control device installed on or in a motor vehicle or engine, and prohibits manufacturing, selling or installing defeat devices.

United States Code

Section 205 of the Clean Air Act sets civil penalty amounts and rules for violations of the motor vehicle emissions provisions.

United States Code

Section 113(c) of the Clean Air Act provides criminal penalties for knowing violations, including tampering-related conduct when charged under the applicable subsection.

United States Code

Section 306 bars federal agencies from contracting with a person convicted of certain Clean Air Act offenses at the facility giving rise to the conviction, until the EPA Administrator certifies that the condition has been corrected.

United States Code

Section 209 preempts state motor vehicle emission standards but allows California to receive a waiver of preemption, which other states may then adopt under § 177.

United States Code

Section 610 of the RFA requires agencies to periodically review rules that have a significant economic impact on a substantial number of small entities.

U.S. Environmental Protection Agency · 2026

EPA has opened a rulemaking docket concerning heavy-duty diesel inducement, nonconformance penalty and derate provisions, and has invited public comment and hearing testimony.

U.S. Environmental Protection Agency · 2026

EPA has scheduled public hearings on the heavy-duty diesel inducement proposal and provided a written-comment period on docket EPA-HQ-OAR-2026-0728.

U.S. Environmental Protection Agency / regulations.gov · 2026

The regulations.gov docket page is the on-record channel for written comments on the heavy-duty inducement proposal.

Code of Federal Regulations

40 CFR 1036.111 specifies diagnostic and inducement requirements for heavy-duty engines, including reduced-power (derate) responses to certain aftertreatment or DEF-related fault conditions.

Code of Federal Regulations

40 CFR 1068.225 provides a conditional exemption for engines used in tactical military vehicles or equipment when certified in accordance with applicable Department of Defense standards.

Code of Federal Regulations

40 CFR 1090.605 permits fuel used for national security purposes to be exempted from certain fuel-content standards under specified conditions.

Code of Federal Regulations

40 CFR Part 1039 establishes the Tier 4 nonroad diesel emission standards and supporting diagnostic and inducement provisions applicable to agricultural and construction equipment.

Code of Federal Regulations

40 CFR Part 1036 is the umbrella regulation setting exhaust-emission standards, useful-life provisions and warranty requirements for on-road heavy-duty engines.

Code of Federal Regulations

40 CFR Part 15 is the implementing regulation for the § 306 federal-contractor listing process, including EPA Administrator listing, notice to the offending facility, and the reinstatement procedure.

U.S. Environmental Protection Agency · 2026

EPA has opened a rulemaking docket concerning heavy-duty diesel inducement, nonconformance penalty and derate provisions, and has invited public comment and hearing testimony.

Code of Federal Regulations

40 CFR 1068.225 provides a conditional exemption for engines used in tactical military vehicles or equipment when certified in accordance with applicable Department of Defense standards.

Code of Federal Regulations

40 CFR 1090.605 permits fuel used for national security purposes to be exempted from certain fuel-content standards under specified conditions.

Code of Federal Regulations

40 CFR Part 1039 establishes the Tier 4 nonroad diesel emission standards and supporting diagnostic and inducement provisions applicable to agricultural and construction equipment.

U.S. Environmental Protection Agency · 2026

EPA has opened a rulemaking docket concerning heavy-duty diesel inducement, nonconformance penalty and derate provisions, and has invited public comment and hearing testimony.

United States Code

Federal law prohibits removing or rendering inoperative any emission control device installed on or in a motor vehicle or engine, and prohibits manufacturing, selling or installing defeat devices.

United States Code

Section 205 of the Clean Air Act sets civil penalty amounts and rules for violations of the motor vehicle emissions provisions.

United States Code

Section 113(c) of the Clean Air Act provides criminal penalties for knowing violations, including tampering-related conduct when charged under the applicable subsection.

U.S. Environmental Protection Agency · annual

EPA publishes annual civil monetary penalty inflation adjustments that set the current maximum per-vehicle, per-violation dollar amount for Clean Air Act mobile-source violations.

U.S. Department of Justice, Environment and Natural Resources Division (public statement); Office of the Deputy Attorney General (internal memorandum, reported) · 2026-01-21

On January 21, 2026 the DOJ Environment and Natural Resources Division publicly stated it is exercising its enforcement discretion to no longer pursue criminal charges under the Clean Air Act for tampering with onboard diagnostic devices in motor vehicles. Reporting seen by CBS News and E&E News/POLITICO describes an accompanying internal memorandum issued by Deputy Attorney General Todd Blanche directing federal prosecutors to drop pending criminal defeat-device cases and to bring no new ones. This is an enforcement policy change — not a statutory repeal. The Clean Air Act (42 U.S.C. §§ 7413(c), 7522, 7524) remains unchanged; EPA civil enforcement is not automatically terminated; existing convictions are not automatically vacated; existing consent decrees are not automatically terminated.

U.S. Environmental Protection Agency, Office of Enforcement and Compliance Assurance · annual

EPA publishes annual enforcement results reporting civil penalties assessed, injunctive relief secured and mobile-source consent decrees entered in each fiscal year.

U.S. Environmental Protection Agency · 2026

EPA has opened a rulemaking docket concerning heavy-duty diesel inducement, nonconformance penalty and derate provisions, and has invited public comment and hearing testimony.

U.S. Environmental Protection Agency · 2026

EPA has scheduled public hearings on the heavy-duty diesel inducement proposal and provided a written-comment period on docket EPA-HQ-OAR-2026-0728.

U.S. Environmental Protection Agency / regulations.gov · 2026

The regulations.gov docket page is the on-record channel for written comments on the heavy-duty inducement proposal.

U.S. Small Business Administration, Office of Advocacy · 2025

SBA attributes $4.4 billion in annual savings to farmers and $13.79 billion in annual savings to Americans from removal or reconsideration of a specific DEF sensor requirement.

U.S. Environmental Protection Agency · January 2026

EPA has restated its approach to monetizing PM2.5 and ozone co-benefits in regulatory impact analyses, prompting the question whether prior diesel rules would survive re-analysis under the current methodology.

U.S. Department of Justice, Environment and Natural Resources Division (public statement); Office of the Deputy Attorney General (internal memorandum, reported) · 2026-01-21

On January 21, 2026 the DOJ Environment and Natural Resources Division publicly stated it is exercising its enforcement discretion to no longer pursue criminal charges under the Clean Air Act for tampering with onboard diagnostic devices in motor vehicles. Reporting seen by CBS News and E&E News/POLITICO describes an accompanying internal memorandum issued by Deputy Attorney General Todd Blanche directing federal prosecutors to drop pending criminal defeat-device cases and to bring no new ones. This is an enforcement policy change — not a statutory repeal. The Clean Air Act (42 U.S.C. §§ 7413(c), 7522, 7524) remains unchanged; EPA civil enforcement is not automatically terminated; existing convictions are not automatically vacated; existing consent decrees are not automatically terminated.

U.S. Congress, House of Representatives · 119th Congress

H.R. 4117 has been introduced in the House. Introduction is a legislative event; it is not enactment. The bill's current status, sponsors and committee referrals are on the record at Congress.gov.

U.S. Congress · 119th Congress

Legislation described publicly as the 'Diesel Truck Liberation Act' has been referenced in Congress. Its bill number, sponsors and text require Congress.gov verification before any final labeling.

American Transportation Research Institute (ATRI) · annual

ATRI's annual operational-cost study reports fleet-level repair-and-maintenance and downtime cost figures, including a growing share attributable to aftertreatment components.

U.S. Congress, House of Representatives · 119th Congress

H.R. 4117 has been introduced in the House. Introduction is a legislative event; it is not enactment. The bill's current status, sponsors and committee referrals are on the record at Congress.gov.

U.S. Congress · 119th Congress

Legislation described publicly as the 'Diesel Truck Liberation Act' has been referenced in Congress. Its bill number, sponsors and text require Congress.gov verification before any final labeling.