; and veterinary assistants and laboratory animal caretakers. (3) Emergency period The term emergency period has the meaning given such term in section 1135(g) of the Social Security Act. (4) Regular rate The term regular rate has the meaning given the term in section 7 of the Fair Labor Standards Act of 1938 ( 29 U.S.C. 207 ). 3. Payroll credit for certain mandatory hazard pay (a) In general In the case of an employer, there shall be allowed as a credit against the tax imposed by section 3111(a) of the Internal Revenue Code of 1986 for each calendar quarter an amount equal to 100 percent of the qualified hazard pay wages paid by such employer with respect to such calendar quarter. (b) Limitations and refundability (1) Credit limited to certain employment taxes The credit allowed by subsection (a) with respect to any calendar quarter shall not exceed the tax imposed by section 3111(a) of such Code for such calendar quarter (reduced by any other credits allowed against such tax for such quarter) on the wages paid with respect to the employment of all employees of the employer. (2) Refundability of excess credit (A) In general If the amount of the credit under subsection (a) exceeds the limitation of paragraph (1) for any calendar quarter, such excess shall be treated as an overpayment that shall be refunded under sections 6402(a) and 6413(b) of such Code. (B) Treatment of payments For purposes of section 1324 of title 31, United States Code, any amounts due to an employer under this paragraph shall be treated in the same manner as a refund due from a credit provision referred to in subsection (b)(2) of such section. (c) Qualified hazard pay wages For purposes of this section, the term qualified hazard pay wages means wages (as defined in section 3121(a) of the Internal Revenue Code of 1986) paid by an employer which are required to be paid by reason of section 2. (d) Special rules (1) Denial of double benefit For purposes of chapter 1 of such Code, the gross income of the employer, for the taxable year which