What the law requires
The federal Worker Adjustment and Retraining Notification Act (1988) applies to employers with 100 or more full-time employees. It requires 60 calendar days of written advance notice before a plant closing that affects 50 or more employees, or a mass layoff affecting 500 or more employees — or 50 to 499 employees if they represent at least one-third of the workforce at a single site.
Notices must be delivered in writing to three distinct recipients: each affected worker individually, the state's dislocated worker unit, and the chief elected official of the local government where the facility is located.
Employers that fail to provide proper notice are liable for up to 60 days of back pay and benefits for each affected employee, plus civil penalties of up to $500 per day to the relevant local government.
A number of states have enacted their own mini-WARN laws with rules that frequently differ from the federal standard — lower employee thresholds, longer notice periods, or different notice recipients. California, New York, and New Jersey are among the most commonly encountered, each with distinct requirements that apply in addition to, not instead of, federal obligations.