40 CFR § 1090.715 - Deficit carryforward.
(a) A gasoline manufacturer incurs a compliance deficit if they exceed the average standard specified in subpart C of this part for a given compliance period. The deficit incurred must be determined as specified in paragraph (a)(1) of this section for sulfur and paragraph (a)(2) of this section for benzene.
(1) The sulfur deficit incurred is determined as follows:
(2) The benzene deficit incurred is determined as follows:
(b) A gasoline manufacturer must use all sulfur or benzene credits previously generated or obtained at any of their facilities to achieve compliance with an average standard specified in subpart C of this part before carrying forward a sulfur or benzene deficit at any of their facilities.
(c) A gasoline manufacturer that incurs a deficit under this section must satisfy that deficit and demonstrate compliance with the annual average standards during the next compliance period regardless of whether the gasoline manufacturer produces gasoline during next compliance period.