Title 42, The Public Health and WelfareRelease 119-110

§7581 Definitions

Title 42 › CHAPTER 85 — AIR POLLUTION PREVENTION AND CONTROL › SUBCHAPTER II — EMISSION STANDARDS FOR MOVING SOURCES › Part C — Clean Fuel Vehicles › § 7581

Last updated Sep 23, 2026|Official source

Summary

Defines key words used in this part. It says which earlier definitions apply and explains key terms in plain ways. Terms from part A: the same meanings apply here. Clean alternative fuel: a fuel or power source (like methanol, ethanol, diesel, natural gas, liquefied petroleum gas, hydrogen, or electricity) that a clean-fuel vehicle is certified to use; mixtures with 85 percent or more alcohol count. Flexible or dual fuel vehicles only get that label for fuels they were certified on, including any California Air Resources Board (CARB) standards that replace those rules. NMOG (nonmethane organic gas): the total of certain hydrocarbons, including oxygenated organics with 5 or fewer carbon atoms and other hydrocarbons with 12 or fewer carbon atoms; testing follows California NMOG procedures and is adjusted for fuel reactivity versus base gasoline. Base gasoline: a specific fuel blend with exact specs (API gravity 57.8; sulfur 317 ppm; color purple; benzene 1.35% vol; Reid vapor pressure 8.7; drivability 1195; antiknock 87.3; distillation IBP 92°F, 10% 126°F, 50% 219°F, 90% 327°F, EP 414°F; aromatics 30.9%, olefins 8.2%, saturates 60.9%). The Administrator may update NMOG, base gasoline, and reactivity methods to match California rules if those are at least as protective. Covered fleet: 10 or more motor vehicles owned or operated by one person, counting vehicles under common control, but excluding rental, dealer sale, manufacturer test, law enforcement/emergency, and nonroad vehicles. Covered fleet vehicle: a vehicle in a class with standards that is in a covered fleet and is centrally fueled or can be centrally fueled (vehicles normally garaged at a personal residence at night are not considered capable of central fueling). Clean-fuel vehicle: a vehicle certified to meet the clean-fuel standards for its class for a model year.

Full Legal Text

Title 42, §7581

The Public Health and Welfare, Source: USLM XML via OLRC

For purposes of this part—

(1)Terms defined in part A

The definitions applicable to part A under section 7550 of this title shall also apply for purposes of this part.

(2)Clean alternative fuel

The term “clean alternative fuel” means any fuel (including methanol, ethanol, or other alcohols (including any mixture thereof containing 85 percent or more by volume of such alcohol with gasoline or other fuels), reformulated gasoline, diesel, natural gas, liquefied petroleum gas, and hydrogen) or power source (including electricity) used in a clean-fuel vehicle that complies with the standards and requirements applicable to such vehicle under this subchapter when using such fuel or power source. In the case of any flexible fuel vehicle or dual fuel vehicle, the term “clean alternative fuel” means only a fuel with respect to which such vehicle was certified as a clean-fuel vehicle meeting the standards applicable to clean-fuel vehicles under section 7583(d)(2) of this title when operating on clean alternative fuel (or any CARB standards which replaces such standards pursuant to section 7583(e) of this title).

(3)NMOG

The term nonmethane organic gas (“NMOG”) means the sum of nonoxygenated and oxygenated hydrocarbons contained in a gas sample, including, at a minimum, all oxygenated organic gases containing 5 or fewer carbon atoms (i.e., aldehydes, ketones, alcohols, ethers, etc.), and all known alkanes, alkenes, alkynes, and aromatics containing 12 or fewer carbon atoms. To demonstrate compliance with a NMOG standard, NMOG emissions shall be measured in accordance with the “California Non-Methane Organic Gas Test Procedures”. In the case of vehicles using fuels other than base gasoline, the level of NMOG emissions shall be adjusted based on the reactivity of the emissions relative to vehicles using base gasoline.

(4)Base gasoline

The term “base gasoline” means gasoline which meets the following specifications:

Specifications of Base Gasoline Used as Basis for Reactivity Readjustment: |

API gravity | 57.8

Sulfur, ppm | 317

Color | Purple

Benzene, vol. % | 1.35

Reid vapor pressure | 8.7

Drivability | 1195

Antiknock index | 87.3

Distillation, D–86 °F |

IBP | 92

10% | 126

50% | 219

90% | 327

EP | 414

Hydrocarbon Type, Vol. % FIA: |

Aromatics | 30.9

Olefins | 8.2

Saturates | 60.9

The Administrator shall modify the definitions of NMOG, base gasoline, and the methods for making reactivity adjustments, to conform to the definitions and method used in California under the Low-Emission Vehicle and Clean Fuel Regulations of the California Air Resources Board, so long as the California definitions are, in the aggregate, at least as protective of public health and welfare as the definitions in this section.

(5)Covered fleet

The term “covered fleet” means 10 or more motor vehicles which are owned or operated by a single person. In determining the number of vehicles owned or operated by a single person for purposes of this paragraph, all motor vehicles owned or operated, leased or otherwise controlled by such person, by any person who controls such person, by any person controlled by such person, and by any person under common control with such person shall be treated as owned by such person. The term “covered fleet” shall not include motor vehicles held for lease or rental to the general public, motor vehicles held for sale by motor vehicle dealers (including demonstration vehicles), motor vehicles used for motor vehicle manufacturer product evaluations or tests, law enforcement and other emergency vehicles, or nonroad vehicles (including farm and construction vehicles).

(6)Covered fleet vehicle

The term “covered fleet vehicle” means only a motor vehicle which is—

(i)in a vehicle class for which standards are applicable under this part; and

(ii)in a covered fleet which is centrally fueled (or capable of being centrally fueled).

No vehicle which under normal operations is garaged at a personal residence at night shall be considered to be a vehicle which is capable of being centrally fueled within the meaning of this paragraph.

(7)Clean-fuel vehicle

The term “clean-fuel vehicle” means a vehicle in a class or category of vehicles which has been certified to meet for any model year the clean-fuel vehicle standards applicable under this part for that model year to clean-fuel vehicles in that class or category.

Reference

Citations & Metadata

Citation

42 U.S.C. § 7581

Title 42, The Public Health and Welfare

Last Updated

Sep 23, 2026

Release point: 119-110