26 U.S.C. § 6421

(a) Nonhighway uses Except as provided in subsection (i), if gasoline is used in an off-highway business use, the Secretary shall pay (without interest) to the ultimate purchaser of such gasoline an amount equal to the amount determined by multiplying the number of gallons so used by the rate at which tax was imposed on such gasoline under section 4081. Except as provided in paragraph (2) of subsection (f) of this section, in the case of gasoline used as a fuel in an aircraft, the Secretary shall pay (without interest) to the ultimate purchaser of such gasoline an amount equal to the amount determined by multiplying the number of gallons of gasoline so used by the rate at which tax was imposed on such gasoline under section 4081. (b) Intercity, local, or school buses (1) Allowance Except as provided in paragraph (2) and subsection (i), if gasoline is used in an automobile bus while engaged in— (A) furnishing (for compensation) passenger land transportation available to the general public, or (B) the transportation of students and employees of schools (as defined in the last sentence of section 4221(d)(7)(C)), the Secretary shall pay (without interest) to the ultimate purchaser of such gasoline an amount equal to the product of the number of gallons of gasoline so used multiplied by the rate at which tax was imposed on such gasoline by section 4081. (2) Limitation in case of nonscheduled intercity or local buses Paragraph (1)(A) shall not apply in respect of gasoline used in any automobile bus while engaged in furnishing transportation which is not scheduled and not along regular routes unless the seating capacity of such bus is at least 20 adults (not including the driver). (c) Exempt purposes If gasoline is sold to any person for any purpose described in paragraph (2), (3), (4), (5), or (6) of section 4221(a), the Secretary shall pay (without interest) to such person an amount equal to the product of the number of gallons of gasoline so sold multiplied by the rate at which tax was imposed on such gasoline by section 4081. The preceding sentence shall apply notwithstanding paragraphs (2) and (3) of subsection (f). Subsection (a) shall not apply to gasoline to which this subsection applies. (d) Time for filing claims; period covered (1) In general Except as provided in paragraph (2), not more than one claim may be filed under subsection (a), not more than one claim may be filed under subsection (b), and not more than one claim may be filed under subsection (c), by any person with respect to gasoline used during his taxable year; and no claim shall be allowed under this paragraph with respect to gasoline used during any taxable year unless filed by such person not later than the time prescribed by law for filing a claim for credit or refund of overpayment of income tax for such taxable year. For purposes of this subsection, a person’s taxable year shall be his taxable year for purposes of subtitle A. (2) Exception For payments per quarter based on aggregate amounts payable under this section and section 6427, see section 6427(i)(2). (3) Application to sales under subsection (c) For purposes of this subsection, gasoline shall be treated as used for a purpose referred to in subsection (c) when it is sold for such a purpose. (e) Definitions For purposes of this section— (1) Gasoline The term “gasoline” has the meaning given to such term by section 4083(a). (2) Off-highway business use (A) In general The term “off-highway business use” means any use by a person in a trade or business of such person or in an activity of such person described in section 212 (relating to production of income) otherwise than as a fuel in a highway vehicle— (i) which (at the time of such use), is registered, or is required to be registered, for highway use under the laws of any State or foreign country, or (ii) which, in the case of a highway vehicle owned by the United States, is used on the highway. (B) Uses in boats (i) In general Except as otherwise provided in this subparagraph, the term “off-highway business use” does not include any use in a motorboat. (ii) Fisheries and whaling The term “off-highway business use” shall include any use in a vessel employed in the fisheries or in the whaling business. (C) Uses in mobile machinery (i) In general The term “off-highway business use” shall include any use in a vehicle which meets the requirements described in clause (ii). (ii) Requirements for mobile machinery The requirements described in this clause are— (I) the design-based test, and (II) the use-based test. (iii) Design-based test For purposes of clause (ii)(I), the design-based test is met if the vehicle consists of a chassis— (I) to which there has been permanently mounted (by welding, bolting, riveting, or other means) machinery or equipment to perform a construction, manufacturing, processing, farming, mining, drilling, timbering, or similar operation if the operation of the machinery or equipment is unrelated to transportation on or off the public highways, (II) which has been specially designed to serve only as a mobile carriage and mount (and a power source, where applicable) for the particular machinery or equipment involved, whether or not such machinery or equipment is in operation, and (III) which, by reason of such special design, could not, without substantial structural modification, be used as a component of a vehicle designed to perform a function of transporting any load other than that particular machinery or equipment or similar machinery or equipment requiring such a specially designed chassis. (iv) Use-based test For purposes of clause (ii)(II), the use-based test is met if the use of the vehicle on public highways was less than 7,500 miles during the taxpayer’s taxable year. This clause shall be applied without regard to use of the vehicle by any organization which is described in section 501(c) and exempt from tax under section 501(a). (f) Exempt sales; other payments or refunds available (1) Gasoline used on farms This section shall not apply in respect of gasoline which was (within the meaning of paragraphs (1), (2), and (3) of section 6420(c)) used on a farm for farming purposes. (2) Gasoline used in aviation This section shall not apply in respect of gasoline which is used as a fuel in an aircraft— (A) in aviation which is not commercial aviation (as defined in section 4083(b)), or (B) in commercial aviation (as so defined) with respect to the tax imposed by section 4081 at the Leaking Underground Storage Tank Trust Fund financing rate and, in the case of fuel purchased after September 30, 1995 , at so much of the rate specified in section 4081(a)(2)(A) as does not exceed 4.3 cents per gallon. (3) Gasoline used in trains In the case of gasoline used as a fuel in a train, this section shall not apply with respect to— (A) the Leaking Underground Storage Tank Trust Fund financing rate under section 4081, and (B) so much of the rate specified in section 4081(a)(2)(A) as does not exceed the rate applicable under section 4041(a)(1)(C)(ii). (g) Applicable laws (1) In general All provisions of law, including penalties, applicable in respect to the tax imposed by section 4081 shall, insofar as applicable and not inconsistent with this section, apply in respect of the payments provided for in this section to the same extent as if such payments constituted refunds of overpayments of the tax so imposed. (2) Examination of books and witnesses For the purpose of ascertaining the correctness of any claim made under this section, or the correctness of any payment made in respect of any such claim, the Secretary shall have the authority granted by paragraphs (1), (2), and (3) of section 7602(a) (relating to examination of books and witnesses) as if the claimant were the person liable for tax. (h) Regulations The Secretary may by regulations prescribe the conditions, not inconsistent with the provisions of this section, under which payments may be made under this section. (i) Income tax credit in lieu of payment (1) Persons not subject to income tax Payment shall be made under subsections (a) and (b) only to— (A) the United States or any agency or instrumentality thereof, a State, a political subdivision of a State, or any agency or instrumentality of one or more States or political subdivisions, or (B) an organization exempt from tax under section 501(a) (other than an organization required to make a return of the tax imposed under subtitle A for its taxable year). (2) Exception Paragraph (1) shall not apply to a payment of a claim filed under subsection (d)(2). (3) Allowance of credit against income tax For allowance of credit against the tax imposed by subtitle A, see section 34. (j) Cross references (1) For civil penalty for excessive claims under this section, see section 6675. (2) For fraud penalties, etc., see chapter 75 (section 7201 and following, relating to crimes, other offenses, and forfeitures). (3) For treatment of an Indian tribal government as a State (and a subdivision of an Indian tribal government as a political subdivision of a State), see section 7871.