7 C.F.R. § 4270.5
(b) Federal Agency preferred procurement programs.
(1) Each Federal Agency will maintain and implement a procurement program that will assure that Qualified Biobased Products are purchased to the maximum extent practicable and that is consistent with applicable provisions of Federal procurement laws. Each procurement program will contain:
(2) In developing their preference program, Federal agencies will adopt one of the following options, or a substantially equivalent alternative, as part of the procurement program:
(i) A policy of awarding contracts on a case-by-case basis to the vendor offering a Qualified Biobased Product composed of the highest percentage of Biobased Content practicable except when such products: