In general—(1) Diesel fuel. (i) If, before April 1, 1983, a person acquires any diesel fuel by any means other than through a transaction subject to tax under section 4041(a)(1) and uses it as a fuel in a diesel powered highway vehicle, the person is liable for a tax under section 4041(a)(2) on the quantity of diesel fuel so used at the appropriate rate set forth in § 48.4041-1(b)(1)(i). If a person acquired any diesel fuel through a transaction which is subject to tax at the rate set forth in paragraph (b)(1)(i) (C) or (D) of § 48.4041-1, and uses it for a use described in paragraph (b) (1) (i) (A) or (B) of § 48.4041-1 the person is liable for an additional tax uder section 4041(a)(2) on the quantity of diesel fuel so used. See § 48.4041-1(b)(1)(i)(E), (F), or (G) for the applicable rate of tax. See section 6427(a) for credit or refund of tax where diesel fuel acquired in a transaction subject to tax at the rate set forth in paragraph (b)(1)(i) (A) or (B) of § 48.4041-1 is used as described in paragraph (b)(1)(i) (C) or (D) of § 48.4041-1 or in a nontaxable use.

On or after April 1, 1983, and before August 1, 1984, if a person acquires any diesel fuel by any means other than through a transaction subject to tax under section 4041(a)(1)(A) and uses it as a fuel in a diesel-powered highway vehicle, the person is liable for a tax under section 4041(a)(1)(B) on the quantity of diesel fuel so used at the appropriate rate set forth in paragraph (b)(1)(ii) of § 48.4041-1. If a person acquired any diesel fuel through a transaction for which no tax is imposed by reason of paragraph (b)(1)(ii)(C) of § 48.4041-1 and uses it in other than a nontaxable use, the person is liable for a tax under section 4041(a)(1)(B) on the quantity of fuel so used. See paragraph (b)(1)(ii) (D) or (E) of § 48.4041-1 for the applicable rate of tax. See section 6427(a) for credit or refund of tax where diesel fuel acquired in a transaction subject to tax at the rate set forth in paragraph (b)(1)(ii)(A) of § 48.4041-1 is used as described in paragraph (b)(1)(ii)(C) of § 48.4041-1 or in another nontaxable use.

On or after August 1, 1984, and before October 1, 1988, if a person acquires any diesel fuel by any means other than through a transaction subject to tax under section 4041(a)(1)(A) and uses it as a fuel in a diesel-powered highway vehicle, the person is liable for a tax under section 4041(a)(1)(B) on the quantity of diesel fuel so used at the appropriate rate set forth in paragraph (b)(1)(iii) of § 48.4041-1. If a person acquired any diesel fuel through a transaction for which no tax is imposed by reason of paragraph (b)(1)(iii)(C) of § 48.4041-1 and uses it in other than a nontaxable use, the person is liable for a tax under section 4041(a)(1)(B) on the quantity of fuel so used. See paragraph (b)(1)(iii)(D) of § 48.4041-1 for the applicable rate of tax. See section 6427(a) for credit or refund of tax where diesel fuel acquired in a transaction subject to tax at the rate set forth in paragraph (b)(1)(iii)(A) of § 48.4041-1 is used as described in paragraph (b)(1)(iii)(C) of § 48.4041-1 or in another nontaxable use.

Special motor fuel. (i) On or after January 1, 1979, and before April 1, 1983, if a person acquired any special motor fuel by any means other than through a transaction subject to tax under section 4041(b)(1) and uses it as a fuel in a motor vehicle or motorboat, the person is liable for a tax under section 4041(b)(2) on the quantity of special motor fuel so used at the appropriate rate set forth in § 48.4041-1(b)(2)(i). If a person acquired any special motor fuel through a transaction with is subject to a tax at the rate set forth in paragraph (b)(2)(i)(C) of § 48.4041-1 and uses it in a use other than one for which the reduced rate applies, the person is liable for an additional tax under section 4041(b)(2) on the quantity of special motor fuel so used. See § 48.4041-1(b)(2)(i) (D) or (E) for the applicable rate of tax. See section 6427(a) for credit or refund of tax where special motor fuel acquired in a transaction subject to tax at the rate set forth in paragraph (b)(2)(i)(A) of § 48.4041-1 is used for a purpose described in paragraph (b)(2)(i)(C) of § 48.4041-1 or in a nontaxable use.

On or after April 1, 1983, and before October 1, 1988, if a person acquired any special motor fuel by any means other than through a transaction subject to tax under section 4041(a)(2)(A) and uses it as a fuel in a motor vehicle or motorboat, the person is liable for a tax under section 4041(a)(2)(B) on the quantity of spcial motor fuel so used at the appropriate rate set forth in paragraph (b)(2)(ii) of § 48.4041-1. If a person acquired any special motor fuel through a transaction for which no tax is imposed by reason of paragraph (b)(2)(ii)(C) of § 48.4041-1 and uses it in other than a nontaxable use, the person is liable for a tax under section 4041(a)(2)(B) on the quantity of fuel so used. See paragraph (b)(2)(ii)(D) of § 48.4041-1 for the applicable rate of tax. See section 6427(a) for credit or refund of tax where special motor fuel acquired in a transaction subject to tax at the rate set forth in paragraph (b)(2)(ii)(A) of § 48.4041-1 is used for a purpose described in paragraph (b)(2)(ii)(C) of § 48.4041-1 or in another nontaxable use.

Noncommercial aviation. If a person acquires any liquid fuel by any means other than through a transaction subject to tax under section 4041(c)(1)(A) or section 4041(c)(2)(A) and uses it as fuel in an aircraft in noncommercial aviation, the person is liable for a tax under section 4041(c)(1)(B) or section 4041(c)(2)(B) on the quantity of the liquid fuel so used at the appropriate rate set forth in § 48.4041-1(b)(3).

Bulk purchases by users. Taxpayers who purchase taxable liquid fuel in bulk delivered into storage tanks or other containers and use it for taxable or nontaxable purposes or in registered and nonregistered vehicles must maintain adequate records of all fuel used for each purpose to permit verification of the tax paid and of any credits, refunds, or exemptions claimed.