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I am very sorry to hear about this situation. On this website, I do not always get to give good news, and this is one of these times. I understand that hearing things less than optimal is not easy, and I empathize. Thanks in advance for not "shooting the messenger."
An employer generally has the right to terminate an employee FOR ANY REASON.
The only reasons one cannot be fired for are:
-PUBLIC POLICY (discrimination based on race, religion, creed, etc; or, a retaliatory termination due to a claim made by an employee); or
-CONTRACT POLICY (if one has a contract that disallows such a termination)
-COVENANT OF GOOD FAITH (firing an employee to avoid paying a benefit, for example)
Otherwise, an employer can terminate for any reason, without notice. It can be based on a mistake (like the mistaken drug test), or, just the fact that they do not like your shirt one day. You will hear "right to work" a lot. However, that does not mean what people think it means. All this means is that at time of being employed, the employee has a choice whether or not to join a union as a condition of employment.
Otherwise, the employer does not owe the employee any "due process" (that is if this was a court matter) or any "redos" on the drug test, so to speak - unless they choose to agree to this, at their discretion.
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