15 U.S.C. § 3374

(a) General rule Any provision of any contract for the first sale of natural gas is hereby declared against public policy and unenforceable with respect to any natural gas covered by this chapter if such provision— (1) prohibits the commingling of natural gas subject to such contract with natural gas subject to the jurisdiction of the Commission under the provisions of the Natural Gas Act [ 15 U.S.C. 717 et seq.]; (2) prohibits the sale of any natural gas subject to such contract to, or transportation of any such natural gas by, any person subject to the jurisdiction of the Commission under the Natural Gas Act [ 15 U.S.C. 717 et seq.], or otherwise prohibits the sale or transportation in interstate commerce (within the meaning of the Natural Gas Act) of natural gas subject to such contract; or (3) terminates, or grants any party the option to terminate, any obligation under any such contract as a result of such commingling, sale, or transportation. (b) Natural gas covered by this chapter For purposes of subsection (a), the term “natural gas covered by this chapter” means— (1) natural gas which is not committed or dedicated to interstate commerce as of November 8, 1978 ; (2) natural gas, the sale in interstate commerce of which— (A) is authorized under section 3362(a) or 3371(b) of this title; or (B) is pursuant to an assignment under section 3372(a) of this title ; and, (3) natural gas, the transportation in interstate commerce of which is— (A) pursuant to any order under section 3362(c) or section 3363(b), (c), (d), or (h) of this title; or (B) authorized by the Commission under section 3371(a) of this title .