# 40 CFR § 85.525: Applicable standards

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/ecfr-40-85.525

## Section

- **Citation:** 40 CFR § 85.525
- **Heading:** Applicable standards
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** September 22, 2026
- **Source:** Publisher's official text
- **Location:** Title 40—Protection of Environment > CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY > SUBCHAPTER C—AIR PROGRAMS > PART 85—CONTROL OF AIR POLLUTION FROM MOBILE SOURCES > Subpart F—Exemption of Clean Alternative Fuel Conversions From Tampering Prohibition

## Text

To qualify for an exemption from the tampering prohibition, vehicles/engines that have been converted to operate on a different fuel must meet emission standards and related requirements as described in this section. The modified vehicle/engine must meet the requirements that applied for the OEM vehicle/engine, or the most stringent OEM vehicle/engine standards in any allowable grouping. Fleet average standards do not apply unless clean alternative fuel conversions are specifically listed as subject to the standards.
(a) If the vehicle/engine was certified with a Family Emission Limit for NOX, NOX+HC, NOX+NMOG, or particulate matter, as noted on the vehicle/engine emission control information label, the modified vehicle/engine may not exceed this Family Emission Limit.
(b) [Reserved]
(c) Conversion systems for engines that would have qualified for chassis certification at the time of OEM certification may use those procedures, even if the OEM did not. Conversion manufacturers choosing this option must designate test groups using the appropriate criteria as described in this subpart and meet all vehicle chassis certification requirements set forth in 40 CFR part 86, subpart S.
[81 FR 73971, Oct. 25, 2016, as amended at 89 FR 28149, Apr. 18, 2024; 91 FR 7759, Feb. 18, 2026]

## Nearby sections

- [40 CFR § 85.501 § 85.501 General applicability.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.501.md)
- [40 CFR § 85.502 § 85.502 Definitions.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.502.md)
- [40 CFR § 85.505 § 85.505 Overview.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.505.md)
- [40 CFR § 85.510 § 85.510 Exemption provisions for new and relatively new vehicles/engines.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.510.md)
- [40 CFR § 85.515 § 85.515 Exemption provisions for intermediate age vehicles/engines.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.515.md)
- [40 CFR § 85.520 § 85.520 Exemption provisions for outside useful life vehicles/engines.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.520.md)
- [40 CFR § 85.525 § 85.525 Applicable standards.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.525.md)
- [40 CFR § 85.530 § 85.530 Vehicle/engine labels and packaging labels.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.530.md)
- [40 CFR § 85.535 § 85.535 Liability, recordkeeping, and end of year reporting.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.535.md)
- [40 CFR § 85.1501 § 85.1501 Applicability.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.1501.md)
- [40 CFR § 85.1502 § 85.1502 Definitions.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.1502.md)
- [40 CFR § 85.1503 § 85.1503 General requirements for importation of nonconforming vehicles and engines.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.1503.md)
- [40 CFR § 85.1504 § 85.1504 Conditional admission.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.1504.md)
- [40 CFR § 85.1505 § 85.1505 Final admission of certified vehicles.](https://www.frixlaw.com/law-library/statutes/ecfr-40-85.1505.md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/ecfr-40-85.525. Check the current official text before relying on it. Not legal advice.