In general. Every person making a claim for credit or payment under section 6421 must keep records sufficient to enable the district director to determine whether the person is entitled to credit or payment under section 6421 and, if so, the amount of the credit or payment. No particular form is prescribed for keeping the records, but the records must include a copy of any statement or document submitted with the return or claim. The records must also show with respect to the period covered by the claim—

The number of gallons of gasoline purchased and the dates of purchase,

The name and address of each vendor from whom gasoline was purchased and the total number of gallons purchased from each,

The number of gallons of gasoline purchased by the claimant and used during the period covered by the claim for nonhighway purposes or in intercity, local or school buses,

Other information as necessary to establish the correctness of the claim.

Acceptable records. (1) Evidence of purchases of gasoline, and the purposes for which it was used, to substantiate claims may include paid duplicate sales invoices or tickets from the gasoline dealer or other vendor, and detailed records of all fuel used which show the amount used for the prescribed purpose and the amount used for other purposes.

Records maintained for Federal or State income tax purposes, or to support claims for refund of a State tax on gasoline, may be used to the extent that they contain the information necessary to substantiate the accuracy of the claim for credit under section 6421. However, the records must show separately the number of gallons of gasoline used for nonhighway purposes or in intercity, local, or school buses during the period covered by the claim.

Place and period for keeping records. (1) All records required by this section must be kept by the claimant at a convenient and safe location within the United States which is accessible to internal revenue officers and shall during normal business hours be available for inspection by internal revenue officers. If the claimant has a principal place of business in the United States, the records must be kept at that place of business.

Records required to substantiate a claim under section 6421 must be maintained for a period of at least 3 years from the last date prescribed for the filing of the claim for credit or payment.