40 CFR § 63.10434
In what form and for how long must I keep my records?
June 9, 2020
(a) Your records must be in a form suitable and readily available for expeditious review.
(b) You must keep each record for 5 years following the date of each record.
(c) You must keep each record onsite for at least 2 years after the date of each record. You may keep the records offsite for the remaining 3 years.