Not later than 30 days after the date of the enactment of this section, the Office of Personnel Management shall prescribe regulations providing for work schedules under which an employee whose personal religious beliefs require the abstention from work during certain periods of time, may elect to engage in overtime work for time lost for meeting those religious requirements. Any employee who so elects such overtime work shall be granted equal compensatory time off from his scheduled tour of duty (in lieu of overtime pay) for such religious reasons, notwithstanding any other provision of law.

In the case of any agency described in subparagraphs (C) through (G) of section 5541(1) of this title, the head of such agency (in lieu of the Office) shall prescribe the regulations referred to in subsection (a) of this section.

Regulations under this section may provide for such exceptions as may be necessary to efficiently carry out the mission of the agency or agencies involved.