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If federal or state anti-discrimination laws cover your business, then you can't fire an employee for a discriminatory reason - such as race, age, or disability.
Retaliatory firings
If, for some reason, your employee reports you to the police or a state or federal agency for some violation, you can't treat the employee differently because of the report - even if the employee is an at-will employee. That's called "whistleblower" protection. For example, if the employee accuses your business of illegally dumping toxic waste and report that to the Environmental Protection Agency ("EPA"), the employee cannot be disciplined for that reason. Even if you want to fire the worker for a different reason, it will appear very suspicious if the employee is fired immediately after filing the report.
See a lawyer who specializes in employment law if an employee makes a retaliation claim against you.
Firing employees for complaining
You probably may not fire an employee for complaining about wages or working conditions- if other employees joined in their complaint.
If two or more workers get together to complain to their employer about their wages or their working conditions, the employer probably can't fire them because of those complaints -because their complaints were "concerted activity" protected by federal law. Their claim would be brought to the National Labor Relations Board, which is the agency that handles labor union complaints. The employee would have to file that claim within 6 months of the date of the firing.
Other prohibited reasons for firing
Some states have rules that protect workers from being fired. Those rules range from protections from firing for engaging in private, off-duty conduct (such as "moonlighting") to protections from firing for the employee's political activity (such as attending a political rally.)
May an employee who quits sue for wrongful termination?
Perhaps the employee can sue for a form of wrongful termination called "constructive discharge."
Generally, a constructive discharge happens when no reasonable person would have stayed in the job under such bad conditions, and the worker tried without success to get you to fix the problem. It's hard to prove a constructive discharge case, and the rules vary from state to state. You should contact a lawyer who specializes in employment law if your employee claims a constructive discharge.
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