In legal proceedings between private litigants:

(a) The proper method for obtaining testimony or records from an employee is to submit a request to agency counsel as provided in §§ 9.13 and 9.15 of this part, not to serve a demand on the employee. Whenever, in a legal proceeding between private litigants, an employee is served with a demand, or receives a request, to testify in that employee's official capacity or produce records, the employee shall immediately notify agency counsel.

(b) If authorized to testify pursuant to these rules, an employee may testify only as to facts within that employee's personal knowledge with regard to matters arising out of his or her official duties.

(1) When the proceeding arises from an accident, an employee may testify only as to personally known facts, not reasonably available from other sources, observed by the employee or uncovered during the employee's investigation of the accident or observed by the employee even if he or she did not investigate the accident. The employee shall decline to testify regarding facts beyond the scope of his or her official duties.

(2) The employee shall not testify to facts that are contained in a report, or any part of a report, unless the employee has obtained permission from agency counsel to disclose the information.

(3) The employee shall not disclose confidential or privileged information unless the employee has obtained permission from agency counsel to disclose the information.

(4) The employee shall not testify as to facts when agency counsel determines that the testimony would not be in the best interest of the Department or the United States if disclosed.

(c) An employee shall not testify as an expert or opinion witness with regard to any matter arising out of the employee's official duties or the functions of the Department. An employee who is asked questions that call for expert or opinion testimony shall decline to answer on the grounds that it is forbidden by this part. Agency counsel shall advise the employee on how to proceed if the presiding officer directs the employee to provide expert or opinion testimony.

(d) An employee shall not provide testimony at a trial or hearing. An employee's testimony shall be limited to a single deposition, affidavit, or set of interrogatories, concerning the circumstances (e.g. an accident) from which the proceeding arose. Where multiple legal proceedings concerning those circumstances are pending, or can occur, it shall be the duty of the private litigant seeking the testimony to ascertain, to the extent feasible, the identities of all parties, or potential parties, to those proceedings and notify them that a deposition has been granted and that they have the opportunity to participate. The private litigant shall submit an affidavit or certification describing the extent of the search for parties and potential parties and listing the names of the parties and potential parties notified.

(e) Where an employee has already provided testimony, any party wishing to obtain further testimony from that employee concerning the same matter or occurrence, whether in the same or a different private legal proceeding, may submit a request to agency counsel to waive the restrictions of paragraph (d) of this section. The request shall, in addition to meeting the requirements of § 9.15 of this part, state why the requester should be permitted to gather additional information despite not having previously requested the information when it had an opportunity to do so, and why the additional testimony is now required and the prior testimony or previously supplied documents are insufficient.