Section 1611.3 - Scope of permissible testimony(a) The statute creating the CSB, 42 U.S.C. 7412(r)(6)(G) , precludes the use or admission into evidence of CSB investigative reports in any suit or action for damages arising from such incidents. This provision would be undermined if expert opinion testimony of CSB employees, which may be reflected in the views of the CSB expressed in its reports, were admitted in evidence or used in litigation arising out of an incident. The CSB relies heavily upon its investigators' opinions in its deliberations. Furthermore, the use of CSB employees as experts to give opinion testimony would impose a significant administrative burden on the CSB's investigative staff.(b) For the reasons stated in paragraph (a) of this section and § 1611.1 , CSB employees may only testify as to the factual information they obtained during the course of an investigation. However, they shall decline to testify regarding matters beyond the scope of their investigation, and they shall not give any expert or opinion testimony.(c) CSB employees may testify about the firsthand information they obtained during an investigation that is not reasonably available elsewhere, including their own factual observations. Consistent with the principles cited in § 1611.1 and this section, current CSB employees are not authorized to testify regarding other employee's observations or reports, or other types of CSB documents, including but not limited to safety recommendations, safety studies, safety proposals, safety accomplishments, reports labeled studies, and analysis reports, as they contain staff analysis and/or CSB conclusions.(d) Consistent with 42 U.S.C. 7412(r)(6)(G) , a CSB employee may not use the CSB's investigation report for any purpose during his testimony.(e) No employee may testify in any matter absent advance approval by the General Counsel as provided in this part.