40 CFR § 1090.305 - ULSD standards.
§ 1090.305 ULSD standards.
(a) Overview. Except as specified in § 1090.300(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.