This has a very positive emotional effect on employees who may be remaining in the organization. Depending on how exiting employees are treated, those who stay may feel suckered, betrayed, or guilty. If those leaving get such a good deal, people might feel that they are suckers for staying. If those leaving get a bad deal, those staying will feel guilty. Survivor's guilt is common when some departments are cut while others stay intact.
Unions are typically big losers in a plant closure.
Sometimes there is deception or misunderstanding. For example, a union may be promised that a plant will remain open in exchange for certain concessions - but these concessions may not be enough for the plant to survive. There are often environmental factors beyond the control of just changing work rules or increasing productivity. Union members and representatives often can feel angry and betrayed. The other common scenario is that a plant closure is announced before a union is informed.