40 CFR § 87.46
Recordkeeping
June 9, 2020
(a) You must keep a copy of any reports or other information you submit to us for at least three years.
(b) Store these records in any format and on any media, as long as you can promptly send us organized, written records in English if we ask for them. You must keep these records readily available. We may review them at any time.