19 C.F.R. § 356.21 – Subpoenas.

(a) Application for issuance of a subpoena. An application for issuance of a subpoena requiring a person to appear and depose or testify at the taking of a deposition or at a hearing shall be made to the administrative law judge. An application for issuance of a subpoena requiring a person to appear and depose or testify and to produce specified documents, papers, books, or other physical exhibits at the taking of a deposition, at a prehearing conference, at a hearing, or under any other circumstances, shall be made in writing to the administrative law judge and shall specify the material to be produced as precisely as possible, showing the general relevancy of the material and the reasonableness of the scope of the subpoena.
(b) Use of subpoena for discovery. Subpoenas may be used by any party for purposes of discovery or for obtaining documents, papers, books, or other physical exhibits for use in evidence, or for both purposes. When used for discovery purposes, a subpoena may require a person to produce and permit the inspection and copying of nonprivileged documents, papers, books, or other physical exhibits which constitute or contain evidence relevant to the subject matter involved and which are in the possession, custody, or control of such person.
(c) Application for subpoenas for nonparty department records or personnel or for records or personnel of other Government agencies.
1. (1) An application for issuance of a subpoena requiring the production of nonparty documents, papers, books, physical exhibits, or other material in the records of the Department, or requiring the appearance of an official or employee of the Department, or requiring the production of records or personnel of other Government agencies shall specify as precisely as possible the material to be produced, the nature of the information to be disclosed, or the expected testimony of the official or employee, and shall contain a statement showing the general relevancy of the material, information, or testimony and the reasonableness of the scope of the application, together with a showing that such material, information, or testimony or their substantial equivalent could not be obtained without undue hardship by alternative means.
2. (2) Such applications shall be ruled upon by the administrative law judge. To the extent that the motion is granted, the administrative law judge shall provide such terms and conditions for the production of the material, the disclosure of the information, or the appearance of the official or employee as may appear necessary and appropriate for the protection of the public interest.
3. (3) No application for a subpoena for production of documents grounded upon the Freedom of Information Act (5 U.S.C. 552) shall be entertained by the administrative law judge.
(d) Motion to limit or quash. Any motion to limit or quash a subpoena shall be filed within 10 days after service thereof, or within such other time as the administrative law judge may allow.
(e) Ex parte rulings on applications for subpoenas. Applications for the issuance of subpoenas pursuant to this section may be made ex parte, and, if so made, such applications and rulings thereon shall remain ex parte unless otherwise ordered by the administrative law judge.
(f) Role of the Under Secretary. If a hearing has not been requested, the party seeking enforcement will ask the Under Secretary to appoint an administrative law judge to rule on applications for issuance of a subpoena under this section.