; and (B) excludes gases to the extent they are— (i) carbon dioxide emitted by the combustion of a covered fuel (as such term is defined in section 9901 of the Internal Revenue Code of 1986, as added by section 3(a) of this Act); or (ii) directly attributable to the production of animals for food or food products. (2) Updates The Administrator shall periodically review and, as appropriate, update the list under paragraph (1). (c) Regulations (1) In general Under the authorities vested in the Administrator by the Clean Air Act ( 42 U.S.C. 7401 et seq.) and any other applicable law (other than this section), the Administrator shall promulgate regulations addressing the contribution of non-auction greenhouse gases to global warming. (2) International competitiveness In promulgating regulations under this subsection, the Administrator shall take into consideration the effect of such regulations on the international competitiveness of businesses and industries of the United States. (d) Schedule (1) In general The regulations under subsection (c) shall ensure that— (A) not later than 4 years after the date of enactment of this Act, requirements take effect to regulate sources which, collectively, emit not less than 25 percent of non-auction greenhouse gases emitted in the United States; (B) not later than 6 years after the date of enactment of this Act, requirements take effect to regulate sources which, collectively, emit not less than 50 percent of non-auction greenhouse gases emitted in the United States; (C) not later than 8 years after the date of enactment of this Act, requirements take effect to regulate sources which, collectively, emit not less than 75 percent of non-auction greenhouse gases emitted in the United States