15-70-712. Recordkeeping. (1) Each compressed natural gas dealer, each liquefied petroleum gas dealer, and each person importing, manufacturing, refining, dealing in, transporting, or storing compressed natural gas or liquefied petroleum gas in this state shall keep all records, receipts, invoices, and other pertinent documents that the department may require and shall produce them for the inspection of the department at any time during regular business hours.

(2) The records, receipts, invoices, and other pertinent documents must be kept for a period of at least 3 years from the date on which the return to which they relate was required to have been made.