40 CFR § 60.2950
Where and in what format must I keep my records?
June 9, 2020
(a) You must keep each record on site for at least 2 years. You may keep the records off site for the remaining 3 years.
(b) All records must be available in either paper copy or computer-readable format that can be printed upon request, unless an alternative format is approved by the Administrator.