Final answer:
According to the WARN Act, employers must provide written notice 60 days before plant closings or large layoffs. The close-out message describing actions taken should be sent within these 60 days.
Step-by-step explanation:
According to the Worker Adjustment and Retraining Notification (WARN) Act, employers with more than 100 employees are required to provide a written notice 60 days prior to plant closings or large layoffs. This notice must be sent to affected employees, their representatives, and the appropriate state dislocated worker unit. The close-out message, which describes the actions taken after the investigation commences, should be sent within these 60 days, after the investigation has concluded.