RCW 47.64.060

All employees engaged in the operation of ferries acquired by the department shall remain subject to the federal social security act and shall be under the state employees' retirement act. The department shall make such deductions from salaries of employees and contributions from revenues of the department as shall be necessary to qualify the employees for benefits under the federal social security act. The appropriate officials are authorized to contract with the secretary of health, education and welfare to effect the coverage.