The date of the enactment of this section, referred to in subsecs. (b)(1)(B)(i), (iii)(II) and (d)(3), is the date of enactment of Pub. L. 117–169, which was approved Aug. 16, 2022.

The date of enactment of this paragraph, referred to in subsec. (f)(8), is the date of enactment of Pub. L. 119–21, which was approved July 4, 2025.

2025—Subsec. (a)(3). Pub. L. 119–21, § 70521(g)(2)(A), amended par. (3) generally. Prior to amendment, par. (3) consisted of subpars. (A) and (B) providing a special rate for the applicable amounts in par. (2) for sustainable aviation fuel and defining “sustainable aviation fuel”.

Subsec. (b)(1)(B)(i). Pub. L. 119–21, § 70521(c)(2), substituted “clauses (ii), (iii), (iv), and (v)” for “clauses (ii) and (iii)”.

Subsec. (b)(1)(B)(iv), (v). Pub. L. 119–21, § 70521(c)(1), added cls. (iv) and (v).

Subsec. (b)(1)(C). Pub. L. 119–21, § 70521(b)(1)(A), added subpar. (C) and struck out former subpar. (C). Prior to amendment, text read as follows:

“(i) In general.—Subject to clause (ii), the Secretary may round the emissions rates under subparagraph (B) to the nearest multiple of 5 kilograms of CO₂e per mmBTU.

“(ii) Exception.—In the case of an emissions rate that is between 2.5 kilograms of CO₂e per mmBTU and -2.5 kilograms of CO₂e per mmBTU, the Secretary may round such rate to zero.”

Subsec. (b)(1)(E). Pub. L. 119–21, § 70521(b)(1)(B), added subpar. (E).

Subsec. (c)(1). Pub. L. 119–21, § 70521(g)(2)(B), substituted “and the $1.00 amount in subsection (a)(2)(B)” for “, the $1.00 amount in subsection (a)(2)(B), the 35 cent amount in subsection (a)(3)(A)(i), and the $1.75 amount in subsection (a)(3)(A)(ii)”.

Subsec. (d)(5)(A)(iv). Pub. L. 119–21, § 70521(e)(1), added cl. (iv).

Subsec. (d)(5)(C). Pub. L. 119–21, § 70521(e)(2), added subpar. (C).

Subsec. (f)(1)(A)(iii). Pub. L. 119–21, § 70521(a)(1), added cl. (iii).

Subsec. (f)(3). Pub. L. 119–21, § 70521(f), inserted at end “The Secretary may prescribe additional related person rules similar to the rule described in the preceding sentence for entities which are not described in such sentence, including rules for related persons with respect to which the taxpayer has reason to believe will sell fuel to an unrelated person in a manner described in subsection (a)(4).”

Subsec. (f)(8). Pub. L. 119–21, § 70521(k)(1), added par. (8).

Subsec. (g). Pub. L. 119–21, § 70521(d), substituted “December 31, 2029” for “December 31, 2027”.

Pub. L. 119–21, title VII, § 70521(a)(2), July 4, 2025, 139 Stat. 276, provided that: “The amendments made by this subsection [amending this section] shall apply to transportation fuel produced after December 31, 2025.”

Pub. L. 119–21, title VII, § 70521(b)(2), July 4, 2025, 139 Stat. 276, provided that: “The amendments made by this subsection [amending this section] shall apply to emissions rates published for transportation fuel produced after December 31, 2025.”

Pub. L. 119–21, title VII, § 70521(c)(3), July 4, 2025, 139 Stat. 277, provided that: “The amendments made by this subsection [amending this section] shall apply to emissions rates published for transportation fuel produced after December 31, 2025.”

Pub. L. 119–21, title VII, § 70521(g)(2)(C), July 4, 2025, 139 Stat. 278, provided that: “The amendments made by this paragraph [amending this section] shall apply to fuel produced after December 31, 2025.”

Pub. L. 119–21, title VII, § 70521(k)(2), July 4, 2025, 139 Stat. 279, provided that: “The amendment made by this subsection [amending this section] shall apply to taxable years beginning after the date of enactment of this Act [July 4, 2025].”

Pub. L. 117–169, title I, § 13704(c), Aug. 16, 2022, 136 Stat. 2003, provided that: “The amendments made by this section [enacting this section and amending sections 25C, 30C, 38, and 4101 of this title] shall apply to transportation fuel produced after December 31, 2024.”