You ever get pulled for randoms month after month?
Mecical Exams and Drug Screens are a part of the norm.. your new employer is just covering his ass. It actually costs him money.... to do this when he doesnt have to.
He's making sure you arent a Workers Comp case waiting to happen... well, to be more technical, his Insurance Carrier is setting the rules... they set ALL OF THE RULES these days on whether or not you can even be hired.
If you can imagine having 35 years of clean driving, no drugs, alcohol or accidents and an insurance company still questioning your record while you stand there with your CLEAN MVR in hand....