---
kind: "section"
citation: "40 C.F.R. § 1090.305"
title: "40"
number: "1090.305"
heading: "ULSD standards."
url: "https://uscodex.org/cfr/40/1090.305"
---

# §1090.305. ULSD standards.

- (a) **Overview.** Except as specified in [§ 1090.300(a)](/cfr/40/1090.300.md?p=a), all diesel fuel (including nonpetroleum diesel fuel) must meet the ULSD per-gallon standards of this section.
- (a) **Overview.** Except as specified in [§ 1090.300(a)](/cfr/40/1090.300.md?p=a), diesel fuel must meet the ULSD per-gallon standards of this section.
- (b) **Sulfur standard.** Maximum sulfur content of 15 ppm.
- (c) **Cetane index or aromatic content.** Diesel fuel must meet one of the following standards:
  - (1) **Minimum cetane index of 40.**
  - (2) **Maximum aromatic content of 35 volume percent.**

## Notes

### Amendments

[85 FR 78469, Dec. 4, 2020, as amended at 91 FR 16500, Apr. 1, 2026]

### Authority

Authority: 42 U.S.C. 7414, 7521, 7522-7525, 7541, 7542, 7543, 7545, 7547, 7550, and 7601.

### Source

Source: 85 FR 78469, Dec. 4, 2020, unless otherwise noted.

### Amendments

[85 FR 78469, Dec. 4, 2020, as amended at 91 FR 16500, Apr. 1, 2026]