US SB3297

Extends the biodiesel fuels tax credit (Section 40A) from its December 31, 2024 expiration date to May 31, 2026, providing an approximately 17-month reinstatement of the credit

Prohibits "double dipping" by preventing taxpayers from claiming both the biodiesel credit under Section 40A and the clean fuel production credit under Section 45Z for the same fuel

Extends related biodiesel mixture credits and refund provisions under Sections 6426(c)(6) and 6427(e)(6)(B) through May 31, 2026

Applies to fuel used or sold after November 30, 2025, creating retroactive coverage for the gap period after the original expiration