5 U.S. Code § 8455. Recovery; restoration of earning capacity

(a)
(1)
If an annuitant receiving a disability retirement annuity from the Fund recovers from the disability before becoming 60 years of age, payment of the annuity terminates on reemployment by the Government or 1 year after the date on which the Office determines that the annuitant has recovered, whichever is earlier.
(2)
If an annuitant receiving a disability annuity from the Fund, before becoming 60 years of age, is restored to an earning capacity fairly comparable to the current rate of pay of the position occupied at the time of retirement, payment of the annuity terminates 180 days after the end of the calendar year in which earning capacity is so restored. Earning capacity is deemed restored if in any calendar year the income of the annuitant from wages or self-employment or both equals at least 80 percent of the current rate of pay of the position occupied immediately before retirement.
(b)
(1)
If an annuitant whose annuity is terminated under subsection (a) is not reemployed in a position in which that individual is subject to this chapter, such individual is deemed, except for service credit, to have been involuntarily separated from the service for the purpose of subchapter II of this chapter as of the date of termination of the disability annuity, and after that termination is entitled to annuity under the applicable provisions of such subchapter.
(2) If an annuitant whose annuity is terminated under subsection (a)(2)—
(A)
is not reemployed in a position subject to this chapter; and
(B)
has not recovered from the disability for which that individual was retired;
the annuity of such individual shall be restored at the applicable rate under section 8452 effective the first of the year following any calendar year in which such individual’s income from wages or self-employment or both is less than 80 percent of the current rate of pay of the position occupied immediately before retirement.
(3)
If an annuitant whose annuity is terminated because of a medical finding that the individual has recovered from disability is not reemployed in a position in which such individual is subject to this chapter, the annuity of such individual shall be restored at the applicable rate under section 8452 effective from the date on which the Office determines that there has been a recurrence of the disability.
(4)
Paragraphs (2) and (3) shall not apply in the case of an annuitant receiving an annuity from the Fund under subchapter II of this chapter.

Title 5: Administrative Personnel