29 C.F.R. § 21.115
(a) An institution, or when appropriate an IRB, shall prepare and maintain adequate documentation of IRB activities, including the following:
(b) The records required by this policy shall be retained for at least 3 years, and records relating to research that is conducted shall be retained for at least 3 years after completion of the research. The institution or IRB may maintain the records in printed form, or electronically. All records shall be accessible for inspection and copying by authorized representatives of the Federal department or agency at reasonable times and in a reasonable manner.
(Approved by the Office of Management and Budget under Control Number 0990-0260)