A bill to prohibit plant closings and mass layoffs by employers of 500 or more employees.

Prohibits plant closings or mass layoffs by employers of 500 or more employees until the adjournment of the 100th Congress or the repeal of this Act, whichever occurs earlier.

Sets forth penalties for violations of this Act. Allows any employee suffering employment loss as a result of a closing or layoff to bring an action in an appropriate U.S. district court for back pay and the cost of related benefits.