https://webapps.dol.gov/elaws/eta/warn/faqs.asp
" Is my employer required to give notice if it declares bankruptcy?
There are two situations under which WARN still applies even though your employer declares bankruptcy. The first situation occurs when your employer knows about the plant closing or mass layoff before filing for bankruptcy and should have given you notice but seeks to use bankruptcy to avoid giving notice. The second situation occurs when the employer continues to run the business in bankruptcy, usually as a debtor in possession. WARN generally does not apply where a bankruptcy trustee is simply liquidating a business.
Two of the exceptions to the notice requirement, the faltering company and unforeseeable business circumstances often come up in bankruptcy cases. The bankruptcy proceeding does change the court in which the WARN claim must be filed, from the U.S. District Court to the Bankruptcy Court. The bankruptcy filing may affect how soon any damages are actually paid to an affected employee. "