(a) Section 10 of the Portal to Portal Act of 1947, 29 U.S.C. 255, which applies to the Equal Pay Act of 1963, 29 U.S.C. 206(d), provides that:
In any action or proceeding based on any act or omission on or after the date of the enactment of this Act, no employer shall be subject to any liability or punishment * * * if he pleads and proves that the act or omission complained of was in good faith in conformity with and in reliance on any written administrative regulation, order, ruling, approval or interpretation * * * or any administrative practice or enforcement policy of [the Commission].
The Commission has determined that only the following documents may be relied upon by any employer as a “ruling, approval or interpretation” or as “evidence of any administrative practice or enforcement policy” of the Commission within the meaning of the statutory provisions quoted above.
(1) A written document, entitled “opinion letter,” signed by the Legal Counsel on behalf of and as approved by the Commission;
(2) A written document issued in the conduct of litigation, entitled “opinion letter,” signed by the General Counsel on behalf of and as approved by the Commission;
(3) A matter published and specifically designated as such in the Federal Register.
(b) An opinion letter issued pursuant to paragraph (a)(1) or (a)(2) of this section, when issued to a specific addressee, has no effect upon circumstances beyond the situation of the specific addressee.