(b) Discovery methods. Parties may obtain discovery by one or more of the following methods:

1. (1) Written interrogatories;
2. (2) Requests for production of documents or things;
3. (3) Requests for admission; or

4. (4) Depositions upon oral examination.

   Unless the Presiding Officer otherwise orders under paragraph (d) of this section, the frequency of use of these methods is not limited.

(c) Scope of discovery. The scope of discovery is as follows:

1. (1) In general. Parties may obtain discovery regarding any matter, not privileged, which is within the Commission's statutory authority and is relevant to the subject matter involved in the proceedings, whether it relates to the claim or defense of the party seeking discovery or to the claim or defense of any other party, 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. It is not ground for objection that the information sought will be inadmissible at the hearing if the information sought appears reasonably calculated to lead to the discovery of admissible evidence.
2. (2) Privilege. Discovery may be denied or limited, or a protective order may be entered, to preserve the privilege of a witness, person, or governmental agency as governed by the Constitution, any applicable Act of Congress, or the principles of the common law as they may be interpreted by the Commission in the light of reason and experience.
3. (3) Hearing preparation: materials. Subject to the provisions of paragraph (c)(4) of this section, a party may obtain discovery of documents and tangible things otherwise discoverable under paragraph (c)(1) of this section and prepared in anticipation of litigation or for hearing by or for another party or by or for that other party's representative (including his attorney or consultant) only upon a showing that the party seeking discovery has substantial need of the materials in the preparation of his case and that he is unable without unique hardship to obtain the substantial equivalent of the materials by other means. In ordering discovery of such materials when the required showing has been made, the Presiding Officer shall protect against disclosure of the mental impressions, conclusions, opinions, or legal theories of an attorney or other representative of a party.

4. (4) Hearing preparation: experts. Discovery of facts known and opinions held by experts, otherwise discoverable under the provisions of paragraph (c)(1) of this section and acquired or developed in anticipation of litigation or for trial, may be obtained only as follows:

   1. (i)

      1. (A) A party may through interrogatories require any other party to identify each person whom the other party expects to call as an expert witness at trial, to state the subject matter on which the expert is expected to testify, to state the substance of the facts and opinions to which the expert is expected to testify, and to provide a summary of the grounds for each opinion.
      2. (B) Upon motion, the Presiding Officer may order further discovery by other means upon a showing of substantial cause and may exercise discretion to impose such conditions, if any, as are appropriate in the case.
   2. (ii) A party may discover facts known or opinions held by an expert who has been retained or specially employed by another party in anticipation of litigation or preparation for trial and who is not expected to be called as a witness at trial only upon a showing of exceptional circumstances under which it is impracticable for the party seeking discovery to obtain facts or opinions on the same subject by other means.
   3. (iii) The Presiding Officer may require as a condition of discovery that the party seeking discovery pay the expert a reasonable fee, but not more than the maximum specified in 5 U.S.C. 3109 for the time spent in responding to discovery.

(d) Protective orders. Upon motion by a party and for good cause shown, the Presiding Officer may make any order which justice requires to protect a party or person from annoyance, embarrassment, competitive disadvantage, oppression, or undue burden or expense, including one or more of the following:

1. (1) That the discovery shall not be had;
2. (2) That the discovery may be had only on specified terms and conditions, including a designation of the time or place;
3. (3) That the discovery shall be had only by a method of discovery other than that selected by the party seeking discovery;
4. (4) That certain matters shall not be inquired into or that the scope of discovery shall be limited to certain matters;
5. (5) That discovery shall be conducted with no one present except persons designated by the Presiding Officer;
6. (6) That a trade secret or other confidential research, development, or commercial information shall not be disclosed or shall be disclosed only in a designated way or only to designated parties; and

7. (7) That responses to discovery shall be placed in camera in accordance with § 1025.45 of these rules.

   If a motion for a protective order is denied in whole or in part, the Presiding Officer may, on such terms or conditions as are appropriate, order that any party provide or permit discovery.