The term "mass layoff" means a reduction in force that:
- Is not the result of a plant closing; and
- Results in an employment loss at the single site of employment during any 30-day period for:
- At least 50-499 employees (excluding any part-time employees) if they represent 33 percent of the total active workforce; or
- At least 500 employees (excluding any part-time employees). In this case, the 33 percent rule does not apply.