The Worker Adjustment and Retraining Notification Act requires employers with 100 or more employees to give 60 calendar days' written notice of a plant closing or mass layoff. A plant closing means 50 or more losing work at one site; a mass layoff means 500 or more, or 50 to 499 where they are at least a third of the workforce at that site. The remedy for failure is back pay and benefits for the notice period.
Who is covered, and who is not
The federal WARN Act applies to employers with 100 or more employees. Below that threshold it does not apply at all, which excludes a large share of the workforce before any other test is reached.
Two triggers. A plant closing affecting 50 or more employees at a single site. Or a mass layoff of 500 or more, or of 50 to 499 where that group is at least a third of the workforce at that site. The single-site condition does a great deal of work: an employer can lay off large numbers across many locations without any one site crossing the line.
What the notice has to do
Sixty calendar days, in writing, before the separation. It goes to affected employees or their representative, to the state dislocated worker unit and to the chief elected local official.
Sixty days is a minimum and not a maximum. Employers frequently give notice and pay through the period without requiring attendance, which is lawful and is the outcome most people actually experience.
The aggregation rule that stops the obvious dodge
Separations within any 90-day period are added together if they would otherwise each fall below the threshold. Without that rule an employer could run four layoffs of forty-nine people and never trigger anything.
It is worth knowing about because it is not obvious from your own position. Three quiet rounds in a quarter can add up to a covered event even though no single round looked like one.
The exceptions, and how narrow they are
Faltering company, where the employer was actively seeking capital and reasonably believed notice would prevent obtaining it. Unforeseeable business circumstances, meaning something sudden and outside reasonable expectation. Natural disaster.
All three shorten notice rather than eliminating it, and the employer must still give as much notice as practicable plus a statement of the reason for shortening it. “Business got difficult” does not qualify; the standard is genuinely unforeseeable.
The remedy, and where you have to go for it
Back pay and benefits for each day of violation, up to 60 days. Enforcement is through federal court — there is no agency that investigates on your behalf, which surprises most people and changes the practical calculation entirely.
That means a WARN claim requires a lawyer and a filing. In practice these are often brought as group actions precisely because the individual amounts rarely justify a solo case.
What WARN does not do
It does not require severance. It does not prevent the layoff or require any justification for it. It does not apply to firings for cause, voluntary departures, or the end of a genuinely temporary project.
It is a notice statute, not a job protection statute. Reading it as protection is the most common misunderstanding, and it leads people to expect something the law never promised.
Check your state before you conclude anything
Several states set lower thresholds, longer notice, or both. New York and New Jersey require 90 days; some states cover employers with 50 employees rather than 100. New Jersey additionally mandates severance based on years of service, which federal law never does.
So a layoff generating no federal obligation can generate a substantial state one. Check the state rule first, because it is the one more likely to apply to you.
What to do if you think notice was short
Keep the notice itself, any announcement, and a record of dates and headcounts — including earlier rounds within the previous 90 days, because of the aggregation rule.
Then speak to an employment lawyer promptly. Most assess these at no cost, deadlines apply, and the documentation is far easier to gather while you still have access to your email.
This is general information rather than legal advice, and a WARN question turns on facts specific to your employer and site.
Common questions
Who does WARN cover?
Employers with 100 or more employees, for plant closings affecting 50 or more, or mass layoffs of 500, or 50 to 499 where they are at least a third of the site's workforce.
How much notice is required?
60 calendar days, in writing, to affected employees, the state dislocated worker unit and local government.
Can an employer split a layoff to avoid it?
Losses within a 90-day window can be aggregated, which is designed to stop exactly that.
What are the exceptions?
Faltering company, unforeseeable business circumstances and natural disaster. Each is narrow, and notice must still be as much as practicable.
What is the remedy?
Back pay and benefits for each day of violation up to 60 days, pursued in federal court rather than through an agency.
Which employers does the WARN Act cover?
Those with 100 or more employees, for plant closings affecting 50 or more at a site, or mass layoffs of 500, or 50-499 where that is at least a third of the site.
How much notice is required?
Sixty calendar days in writing, to employees or their representative, the state dislocated worker unit and the chief elected local official.
How is WARN enforced?
Through federal court, with back pay and benefits up to 60 days. No agency investigates on your behalf, which is why these are often brought as group actions.