Employers must closely observe employees for signs and symptoms of heat-related illness by implementing one or more of the close observation options under WAC 296-307-09747(2).

(1) For 14 days when employees:

(a) Are newly assigned to working at or above the applicable temperatures listed in Table 1 of WAC 296-307-09730;

(b) Return to work at the applicable temperatures listed in Table 1 of WAC 296-307-09730 after an absence of seven days or more;

(2) During a heat wave. For purposes of this section only, "heat wave" means any day in which the predicted high temperature for the day will be at least the temperatures listed in Table 1 of WAC 296-307-09730 and at least 10 degrees Fahrenheit higher than the average high daily temperature in the preceding five days.