State agency employees participating in an interchange may be carried on detail or in a leave of absence status.

(1) Wherever practicable, employees should be carried on detail. While on detail under an interchange agreement, employees shall remain employees of the state agency for all fiscal purposes, but shall receive no reimbursement for travel or other expenses except as provided in RCW 41.04.150.

(2) State agency employees who receive temporary appointments with federal agencies shall be carried by the state agency in a leave of absence status. Participation in an interchange shall be considered as service under any retirement system of which the employees are members. Arrangements for payment of employees' contributions to a retirement system may be by the interchange agreement or otherwise. Employees participating in an interchange shall be entitled to credit the full period toward promotion or salary increase as provided by any applicable civil service laws or regulations.