My job is considering introducing pot testing. Just pot testing. Not drug testing in general. Just pot. We are located in New Hampshire, 5 minutes from the Mass border and most of the employees are Mass residents. There was no pre employment drug screening and when I was hired the HR rep said she didn't do drug testing because she wouldn't have a work force. So I guess my question is this: if drug screening was not a condition of my employment at the time of my hiring, can I be subject to firing on the basis of a failed pot test? Are they allowed to do this or are they just bluffing?