The Administrator, or any of his duly authorized agents, shall have the power to require by subpena the attendance and testimony of witnesses, and the production of all information, documents, reports, answers, records, accounts, papers, and other data and documentary evidence which the Administrator is authorized to obtain pursuant to this section.

Any appropriate United States district court may, in case of contumacy or refusal to obey a subpena issued pursuant to this section, issue an order requiring the party to whom such subpena is directed to appear before the Administration and to give testimony touching on the matter in question, or to produce any matter described in paragraph (1) of this subsection, and any failure to obey such order of the court may be punished by such court as a contempt thereof.