40 CFR 1611.9 - Testimony in Federal, State, or local criminal investigations and other proceedings.
(a) As with civil litigation, the CSB prefers that testimony be taken by deposition if court rules permit, and that testimony await the issuance of the investigation report. The CSB recognizes, however, that in the case of coroner's inquests and grand jury proceedings this may not be possible. The CSB encourages those seeking testimony of CSB employees to contact the General Counsel as soon as such testimony is being considered. Whenever the intent to seek such testimony is communicated to the employee, he shall immediately notify the General Counsel.
(b) In any case, CSB employees are prohibited from testifying in any civil, criminal, or other matter, either in person or by deposition or interrogatories, absent advance approval of the General Counsel.
(c) If permission to testify by deposition or in person is granted, testimony shall be limited as set forth in § 1611.3. Only factual testimony is authorized; no expert or opinion testimony shall be given.