5 U.S. Code § 5942a. Separate maintenance allowance for duty at Johnston Island
(a) Notwithstanding section 5536 of this title, and under regulations prescribed by the President, an employee of an Executive agency (other than a Government corporation) who is assigned to a post of duty at Johnston Island, a possession of the United States in the Pacific Ocean, is entitled to receive a separate maintenance allowance if the head of the employing agency finds that—
(1) it is necessary for the employee to maintain the employee’s spouse or dependents, or both, at a location other than Johnston Island—
for the convenience of the Federal Government; and
The regulations prescribed by the President shall include provisions for determining the rate at which an allowance under this section shall be paid.
“The amendments made by subsection (a) [enacting this section] shall take effect on the first day of the first month beginning on or after the date of the enactment of this Act [Dec. 5, 1991].”