; Regional Transmission Organization The terms Independent System Operator and Regional Transmission Organization have the meanings given those terms in section 3 of the Federal Power Act ( 16 U.S.C. 796 ). (4) Modification The term modification includes a reversal of flow direction, change in ownership, change in flow volume, addition or removal of an interconnection, or an adjustment to maintain flow (such as a reduction or increase in the number of pump or compressor stations). (5) Natural gas The term natural gas has the meaning given that term in section 2 of the Natural Gas Act ( 15 U.S.C. 717a ). (6) Oil The term oil means petroleum or a petroleum product. (b) Authorization of certain energy infrastructure projects at an international boundary of the United States (1) In general Except as provided in paragraph (3) and subsection (e), no person may construct, connect, operate, or maintain a border-crossing facility for the import or export of oil or natural gas, or the transmission of electricity, across an international border of the United States without obtaining a certificate of crossing for the border-crossing facility under this subsection. (2) Certificate of crossing (A) Requirement Not later than 120 days after the date on which final action is taken by the relevant official or agency described in subparagraph (B) under the National Environmental Policy Act of 1969 ( 42 U.S.C. 4321 et seq. ) with respect to a border-crossing facility for which a person requests a certificate of crossing under this subsection, the relevant official or agency, in consultation with appropriate Federal agencies, shall issue a certificate of crossing for the border-crossing facility unless the relevant official or agency finds that the construction, connection, operation, or maintenance of the border-crossing facility is not in the public interest of the United States. (B) Relevant official or agency described The relevant official or agency referred to in subparagraph (A) is— (i) the Federal Energy Regulatory Commission