29 U.S.C. § 177
A board of inquiry shall be composed of a chairman and such other members as the President shall determine, and shall have power to sit and act in any place within the United States and to conduct such hearings either in public or in private, as it may deem necessary or proper, to ascertain the facts with respect to the causes and circumstances of the dispute.
Members of a board of inquiry shall receive compensation at the rate of $50 for each day actually spent by them in the work of the board, together with necessary travel and subsistence expenses.
For the purpose of any hearing or inquiry conducted by any board appointed under this title, the provisions of sections 49 and 50 of title 15 (relating to the attendance of witnesses and the production of books, papers, and documents) are made applicable to the powers and duties of such board.
29 U.S.C. § 177