; and (ii) the total amount of nationwide firefighting foam concentrate, in gallons. (B) Determination of grant amounts From the amounts appropriated to carry out the PFAS replacement program that remain after the application of paragraph (1), the Secretary shall make a grant to each eligible airport of the amount equal to the product of— (i) the amount of such remaining funds; and (ii) the ratio of the amount determined under subparagraph (A)(i) for such eligible airport to the amount determined under subparagraph (A)(ii). (c) Program requirements (1) In general The Secretary shall determine the eligibility of costs payable under the PFAS replacement program by taking into account all engineering, technical, and environmental protocols and generally accepted industry standards that are developed or established for fluorine-free foams. (2) Compliance with applicable law All actions related to the acquisition, disposal, and transition to fluorine-free foams, including the cleaning and disposal of equipment, shall be conducted in full compliance with all applicable Federal laws in effect at the time of obligation in order to be eligible for reimbursement under the PFAS replacement program. (3) Government share The Government’s share of allowable costs under the PFAS replacement program shall be 100 percent. (d) Authorization of appropriations (1) In general There is authorized to be appropriated not more than $350,000,000 to carry out the PFAS replacement program. (2) Requirements Amounts appropriated to carry out the PFAS replacement program shall— (A) remain available for expenditure for a period of 5 fiscal years