(1) The term “mass layoff” means a reduction in force which first, is not the result of a plant closing, and second, results in an employment loss at the single site of employment during any 30-day period for:
(i) At least 33 percent of the active employees, excluding part-time employees, and
(ii) At least 50 employees, excluding part-time employees.
(2) Workers, other than part-time workers, who are exempt from notice under section 4 of WARN are nonetheless counted as employees for purposes of determining coverage as a plant closing or mass layoff. For example, if an employer closes a temporary project on which 10 permanent and 40 temporary workers are employed, a covered plant closing has occurred although only 10 workers are entitled to notice.