can you get fired for a drug test that came up positive for weed if you dont operate machinary at the job?

Objective observations of articulable symptoms of impairment. Just smelling is not enough. Just observing bloodshot eyes is not enough. It really depends on how he or others observed you performing your duties. And maybe your supervisor only noticed you make an error or mistake and required a drug test. An employer is unlikely to argue smell prompted testing. Your best test of whether you did not commit gross negligence will probably be when you apply for unemployment. Almost anyone qualifies for unemployment in New York so if you are denied that will speak volumes about any potential discrimination claim which you have not referenced. Employers can and do make mistakes and unless they discriminate by doing so, what's the cause of action?  You might be protected if you were once addicted to drugs or alcohol, were in rehabilitation and no longer abused drugs or alcohol, and you were fired. Or maybe your supervisor thought you were under the influence, sent you for testing based solely on his smelling marijuana, and your test produced a false positive, and your performance was not impaired with or without testing, you might have a claim. You state that you used to do the night time shift with him and it wasn't an issue because almost everybody smokes weed. Assuming that was before marijuana legalization how would that help? Employers can change policies or change how they enforce policies as long as everyone is treated similarly. If you were driving 85 mph down the interstate and were pulled over could you argue that 10 cars just passed you going more that 85 so the cop should have pulled them or everyone over? You drove the car a cop thought "I have enough on this guy to uphold a ticket" and only you were pulled over, so how does that argument work? When everyone violates a presumed policy against impairment at work everyone has to work without fault to avoid discipline, erst the first person who is observed performing below "standards" may lose their job even when others unseen performed worse. The employee must have facts which support a plausible theory of discrimination. Having your manager know you smoke weed anywhere is never a good thing, legal or not. Sharing personal information at work often causes bad outcomes. See this link: https://www.jdsupra.com/legalnews/nysdol-issues-guidance-regarding-the-9960323/