28 C.F.R. § 68.18

(a) General. The parties shall not file requests for discovery, answers, or responses thereto with the Administrative Law Judge. The Administrative Law Judge may, however, upon motion of a party or on his or her own initiative, order that such requests for discovery, answers, or responses thereto be filed. Parties may obtain discovery by one or more of the following methods: depositions upon oral examination or written questions; written interrogatories; production of documents or things, or permission to enter upon land or other property, for inspection and other purposes; physical and mental examinations; and requests for admissions. The frequency or extent of these methods may be limited by the Administrative Law Judge upon his or her own initiative or pursuant to a motion under paragraph (c) of this section.

(b) Scope of discovery. Unless otherwise limited by order of the Administrative Law Judge in accordance with the rules in this part, the parties may obtain discovery regarding any matter, not privileged, which is relevant to the subject matter involved in the proceeding, including the existence, description, nature, custody, condition, and location of any books, documents, or other tangible things, and the identity and location of persons having knowledge of any discoverable matter.

(c) Protective orders. Upon motion by a party or the person from whom discovery is sought, and for good cause shown, the Administrative Law Judge may make any order that justice requires to protect a party or person from annoyance, harassment, embarrassment, oppression, or undue burden or expense, including one or more of the following:

(1) The discovery not be had;

(2) The discovery may be had only on specified terms and conditions, including a designation of the time, amount, duration, or place;

(3) The discovery may be had only by a method of discovery other than that selected by the party seeking discovery; or

(4) Certain matters not relevant may not be inquired into, or that the scope of discovery be limited to certain matters.

(d) Supplementation of responses. A party who has responded to a request for discovery with a response that was complete when made is under no duty to supplement his or her response to include information thereafter acquired, except as follows:

(1) A party is under a duty to supplement timely his or her response with respect to any question directly addressed to:

(i) The identity and location of persons having knowledge of discoverable matters; and

(ii) The identity of each person expected to be called as an expert witness at the hearing, the subject matter on which he or she is expected to testify, and the substance of his or her testimony.

(2) A party is under a duty to amend timely a prior response if he or she later obtains information upon the basis of which:

(i) He or she knows the response was incorrect when made; or

(ii) He or she knows that the response, though correct when made, is no longer true and the circumstances are such that a failure to amend the response is in substance a knowing concealment.

(3) A duty to supplement responses may be imposed by order of the Administrative Law Judge upon motion of a party or agreement of the parties.