Arizona Republic:  “A new state law, signed by Gov. Jan Brewer on Friday, could shield some employers from lawsuits if they wish to fire workers who are under the influence of medical marijuana or prescription drugs on the job.  Another provision in the law allows employers with a qualifying drug-testing policy to reassign or lay off workers who take such medications if they have a job with possible safety risks.  The law, House Bill 2541, takes effect immediately.”