US Code

Public Law 119-73 (01/23/2026)

42 U.S.C. § 7543

State standards

(a)

Prohibition

No State or any political subdivision thereof shall adopt or attempt to enforce any standard relating to the control of emissions from new motor vehicles or new motor vehicle engines subject to this part. No State shall require certification, inspection, or any other approval relating to the control of emissions from any new motor vehicle or new motor vehicle engine as condition precedent to the initial retail sale, titling (if any), or registration of such motor vehicle, motor vehicle engine, or equipment.

(b)

Waiver

(1)
The Administrator shall, after notice and opportunity for public hearing, waive application of this section to any State which has adopted standards (other than crankcase emission standards) for the control of emissions from new motor vehicles or new motor vehicle engines prior to , if the State determines that the State standards will be, in the aggregate, at least as protective of public health and welfare as applicable Federal standards. No such waiver shall be granted if the Administrator finds that—
(A)
the determination of the State is arbitrary and capricious,
(B)
such State does not need such State standards to meet compelling and extraordinary conditions, or
(C)
section 7521(a) of this title such State standards and accompanying enforcement procedures are not consistent with .
(2)
If each State standard is at least as stringent as the comparable applicable Federal standard, such State standard shall be deemed to be at least as protective of health and welfare as such Federal standards for purposes of paragraph (1).
(3)
In the case of any new motor vehicle or new motor vehicle engine to which State standards apply pursuant to a waiver granted under paragraph (1), compliance with such State standards shall be treated as compliance with applicable Federal standards for purposes of this subchapter.
(c)

Certification of vehicle parts or engine parts

section 7541(a)(2) of this titleWhenever a regulation with respect to any motor vehicle part or motor vehicle engine part is in effect under , no State or political subdivision thereof shall adopt or attempt to enforce any standard or any requirement of certification, inspection, or approval which relates to motor vehicle emissions and is applicable to the same aspect of such part. The preceding sentence shall not apply in the case of a State with respect to which a waiver is in effect under subsection (b).

(d)

Control, regulation, or restrictions on registered or licensed motor vehicles

Nothing in this part shall preclude or deny to any State or political subdivision thereof the right otherwise to control, regulate, or restrict the use, operation, or movement of registered or licensed motor vehicles.

(e)

Nonroad engines or vehicles

(1)

Prohibition on certain State standards

No State or any political subdivision thereof shall adopt or attempt to enforce any standard or other requirement relating to the control of emissions from either of the following new nonroad engines or nonroad vehicles subject to regulation under this chapter—
(A)
New engines which are used in construction equipment or vehicles or used in farm equipment or vehicles and which are smaller than 175 horsepower.
(B)
New locomotives or new engines used in locomotives.
Subsection (b) shall not apply for purposes of this paragraph.
(2)

Other nonroad engines or vehicles

(A)
In the case of any nonroad vehicles or engines other than those referred to in subparagraph (A) or (B) of paragraph (1), the Administrator shall, after notice and opportunity for public hearing, authorize California to adopt and enforce standards and other requirements relating to the control of emissions from such vehicles or engines if California determines that California standards will be, in the aggregate, at least as protective of public health and welfare as applicable Federal standards. No such authorization shall be granted if the Administrator finds that—
(i)
the determination of California is arbitrary and capricious,
(ii)
California does not need such California standards to meet compelling and extraordinary conditions, or
(iii)
California standards and accompanying enforcement procedures are not consistent with this section.
(B)
Any State other than California which has plan provisions approved under part D of subchapter I may adopt and enforce, after notice to the Administrator, for any period, standards relating to control of emissions from nonroad vehicles or engines (other than those referred to in subparagraph (A) or (B) of paragraph (1)) and take such other actions as are referred to in subparagraph (A) of this paragraph respecting such vehicles or engines if—
(i)
such standards and implementation and enforcement are identical, for the period concerned, to the California standards authorized by the Administrator under subparagraph (A), and
(ii)
California and such State adopt such standards at least 2 years before commencement of the period for which the standards take effect.
The Administrator shall issue regulations to implement this subsection.

July 14, 1955, ch. 360Pub. L. 90–148, § 281 Stat. 501Pub. L. 91–60484 Stat. 1694Pub. L. 95–95, title II91 Stat. 755Pub. L. 101–549, title II, § 222(b)104 Stat. 2502(, title II, § 209, formerly § 208, as added , , ; renumbered and amended , §§ 8(a), 11(a)(2)(A), 15(c)(2), , , 1705, 1713; , §§ 207, 221, , , 762; , , .)

Editorial Notes

Codification

section 1857f–6a of this titleSection was formerly classified to .

Prior Provisions

Pub. L. 90–148, § 281 Stat. 502Pub. L. 91–604section 7544 of this titleA prior section 209 of act , as added , , , was renumbered section 210 by and is classified to .

act July 14, 1955, ch. 360, title IIPub. L. 89–272, title I, § 101(8)79 Stat. 995section 1857f–8 of this titlePub. L. 89–675, § 2(b)80 Stat. 954Another prior section 209 of , as added , , , related to appropriations for the fiscal years ending , 1967, 1968, and 1969, and was classified to , prior to repeal by , , .

Amendments

Pub. L. 101–5491990—Subsec. (e). added subsec. (e).

Pub. L. 95–95, § 207section 7521(a) of this title1977—Subsec. (b). , designated existing provisions as par. (1), substituted “, if the State determines that the State standards will be, in the aggregate, at least as protective of public health and welfare as applicable Federal standards” for “, unless he finds that such State does not require standards more stringent than applicable Federal standards to meet compelling the extraordinary conditions or that such State standards and accompanying enforcement procedures are not consistent with ”, added subpars. (A), (B), and (C), and added pars. (2) and (3).

Pub. L. 95–95, § 221Subsecs. (c), (d). , added subsec. (c) and redesignated former subsec. (c) as (d).

Pub. L. 91–604, § 11(a)(2)(A)1970—Subsec. (a). , substituted “part” for “subchapter”.

Pub. L. 91–604, § 15(c)(2)Subsec. (b). , substituted “Administrator” for “Secretary”.

Pub. L. 91–604, § 11(a)(2)(A)Subsec. (c). , substituted “part” for “subchapter”.

Statutory Notes and Related Subsidiaries

Effective Date of 1977 Amendment

Pub. L. 95–95section 406(d) of Pub. L. 95–95section 7401 of this titleAmendment by effective , except as otherwise expressly provided, see , set out as a note under .

Modification or Rescission of Rules, Regulations, Orders, Determinations, Contracts, Certifications, Authorizations, Delegations, and Other Actions

Pub. L. 95–95Pub. L. 95–95section 406(b) of Pub. L. 95–95section 7401 of this titleAll rules, regulations, orders, determinations, contracts, certifications, authorizations, delegations, or other actions duly issued, made, or taken by or pursuant to act , the Clean Air Act, as in effect immediately prior to the date of enactment of [] to continue in full force and effect until modified or rescinded in accordance with act , as amended by [this chapter], see , set out as an Effective Date of 1977 Amendment note under .