31 U.S.C. § 1515

(a) An appropriation required to be apportioned under section 1512 of this title may be apportioned on a basis that indicates the need for a deficiency or supplemental appropriation to the extent necessary to permit payment of such pay increases as may be granted pursuant to law to civilian officers and employees (including prevailing rate employees whose pay is fixed and adjusted under subchapter IV of chapter 53 of title 5) and to retired and active military personnel. (b) (1) Except as provided in subsection (a) of this section, an official may make, and the head of an executive agency may request, an apportionment under section 1512 of this title that would indicate a necessity for a deficiency or supplemental appropriation only when the official or agency head decides that the action is required because of— (A) a law enacted after submission to Congress of the estimates for an appropriation that requires an expenditure beyond administrative control; or (B) an emergency involving the safety of human life, the protection of property, or the immediate welfare of individuals when an appropriation that would allow the United States Government to pay, or contribute to, amounts required to be paid to individuals in specific amounts fixed by law or under formulas prescribed by law, is insufficient. (2) If an official making an apportionment decides that an apportionment would indicate a necessity for a deficiency or supplemental appropriation, the official shall submit immediately a detailed report of the facts to Congress. The report shall be referred to in submitting a proposed deficiency or supplemental appropriation.