(1) Shift premium at the rate specified in the compensation plan must be paid when:

(a) An employee is regularly scheduled to work a shift in which the majority of hours worked daily or weekly are between 6:00 p.m. and 6:00 a.m.;

(b) An employee is scheduled to work a shift which is split with a minimum of four intervening hours not worked; or

(c) An employee is regularly scheduled to work a day shift but is assigned to work a night or evening shift in which the majority of hours worked are between 6:00 p.m. and 6:00 a.m.

(2) Shift premium must be paid for the entire daily or weekly shift that qualifies under subsection (1) of this section. Additionally, these employees are entitled to shift premium for all hours that the employees work adjoining that evening or night shift.

(3) Shift premium may be paid at a monthly rate as specified in the compensation plan for full time employees regularly assigned to a qualifying shift.

(4) An employee assigned to a shift that qualifies for shift premium pay must receive the same shift premium for authorized periods of paid leave and holidays and for up to five days of a temporary assignment to a shift that does not qualify. Continued payment of shift premium for a temporary assignment exceeding five days is at the discretion of the employer.

(5) Compensation under the provisions of this section must be in accordance with the employer's policy, as approved by the director, for the following individuals:

(a) Employees dispatched to emergency response duty under an incident command system as defined in RCW 38.52.010; and

(b) Employees of the department of corrections who are in charge of offenders assigned to assist in forest fire suppression and other emergency incidents.

(6) Exceptions to shift premium provisions may be approved by the director.

(7) For higher education employers, shift premium must not apply to police and fire officers where special pay salaries are correlated with a rotating shift in accordance with local practice.

(8) Employees may waive shift premium.

(9) Employees who voluntarily request to work a shift as described in subsection (1)(a), (b), and (c) of this section will not be eligible for shift premium.