The federal Worker Adjustment and Retraining Notification Act (“WARN ACT”) (29 U.S. Code §§ 2101 et seq.) and the California WARN (Cal. Lab. Code §§ 1400 et seq.) offer protection to workers, their families, and communities by requiring employers to provide notice 60 days in advance of covered plant closings and mass layoffs. This notice must be provided to either affected workers or their representatives (e.g., a labor union), to the state dislocated worker unit, and to the appropriate unit of local government.


Employers are covered by WARN if they have 100 or more employees, excluding employees who have worked less than 6 months in the last 12 months, and not counting employees who work an average of less than 20 hours a week. Federal, State, and local government entities that provide public services are not covered by WARN.

California employers are covered by the California WARN if they have 75 or more full or part-time employees.

What Triggers Notice

Plant Closing: A covered employer must give notice if an employment site will be shut down, and the shutdown will result in an employment loss for 50 or more employees during any 30-day period.

Mass Layoff: A covered employer must give notice if there is to be a mass layoff which does not result from a plant closing, but which will result in an employment loss at the employment site during any 30-day period for 500 or more employees, or for 50-499 employees, if they make up at least 33% of the employer’s active workforce.

Any plant closing or mass layoff occurring as part of, or contemporaneously with, a business sale must be preceded by WARN notice. The seller is responsible for providing such notice for a plant closing or mass layoff that occurs before or on the effective date of the sale. After that, the buyer is responsible for providing the required WARN notice.


A covered employer that violates the WARN notice requirement can be liable to each affected employee for an amount equal to back pay and benefits for the period of violation up to 60 days, as well as civil penalties.