for work of mutual concern to his agency and the State or local government that he determines will be beneficial to both. The period of an assignment under this subchapter may not exceed two years. However, the head of a Federal agency may extend the period of assignment for not more than two additional years. In the case of assignments made to Indian tribes or tribal organizations as defined in section 3371(2)(C) of this subchapter, the head of an executive agency may extend the period of assignment for any period of time where it is determined that this will continue to benefit both the executive agency and the Indian tribe or tribal organization. If the assigned employee fails to complete the period of assignment and there is another employee willing and available to do so, the Secretary may assign the employee to complete the period of assignment and may execute an agreement with the tribal organization with respect to the replacement employee. That agreement may provide for a different period of assignment as may be agreed to by the Secretary and the tribal organization.
An employee assigned either on detail or on leave without pay remains an employee of his agency. The Federal Tort Claims Act and any other Federal tort liability statute apply to an employee so assigned. The supervision of the duties of an employee on detail may be governed by agreement between the Federal agency and the State or local government concerned.
However, an employee or his beneficiary may not receive benefits referred to in subparagraphs (A) and (B) of this paragraph (3), based on service during an assignment under this subchapter for which the employee or, if he dies without making such an election, his beneficiary elects to receive benefits, under any State or local government retirement or insurance law or program, which the Office of Personnel Management determines to be similar. The Federal agency shall deposit currently in the Employees Life Insurance Fund, the Employees Health Benefits Fund or other applicable health benefits system, respectively, the amount of the Governments contributions on account of service with respect to which employee contributions are collected as provided in subparagraphs (A) and (B) of this paragraph (3).
The above exceptions shall not apply to non-Federal employees who are covered by chapters 83, 87, and 89 of this title by virtue of their non-Federal employment immediately before assignment and appointment under this section.
The supervision of the duties of such an employee may be governed by agreement between the Federal agency and the State or local government concerned. A detail of a State or local government employee to a Federal agency may be made with or without reimbursement by the Federal agency for the pay, or a part thereof, of the employee during the period of assignment, or for the contribution of the State or local government, or a part thereof, to employee benefit systems.