Sure it is your right as owner. Private Companies; along with publicly held, have no drug use policies in their terms of employment across this country. I believe it more depends on the state you are in.
Many here will probably agree, at the FEDERAL level, this war on drugs needs to cease. Let the states and their voters decide what a citizen can do within that state.
I'm all for ending the war on drugs, don't get me wrong, I'm also for ending the war on business and the war on irresponsibility as well. If someone chhoses to live whatever lifestyle they want, they also have to be prepared for whatever consequences come with it. Current laws don't support that.