Utility Workers Union of America
AFL - CIO Local 127

The contract sets the criteria under which your employer can cut hours or lay off employees.  For example, it may be necessary for the employer to prove that there is a “compelling business necessity” to justify any shrinking of the workforce.  And the contract will cover how it is determined which employees get to keep their jobs and which don’t.  (This is often determined by seniority, that is, length of service with the employer.)  There may be detailed procedures including such items as how much notice must be given, determination of severance pay, retraining rights, and priority for being rehired in the future.
—Adapted from The Union Member's Complete Guide, by Michael Mauer