Can my employer fire me for legally using marijuana?

Changing marijuana laws aren’t necessarily making weed more welcome in the workplace. For now, many employers appear to be sticking with their drug testing and personal conduct policies, even in states where recreational marijuana use is now permitted. Others are keeping a close eye on the still evolving legal, regulatory and political environment.
Read more: http://www.denverpost.com/2016/12/04/can-my-employer-fire-me-for-legally-using-marijuana/?source=Snapzu