The company has what Burke called a “reasonable suspicion” drug-testing policy that calls for a urine sample when the company suspects its employees are under-the-influence on the job. Burke said the policy is for the safety of its employees.
This should be the model, if someone is doing something out of the ordinary on the job that makes someone suspect he's under the influence then in that case even I agree testing is fair, as long as the people making the judgment call on whether an employee is high or not has some training to judge such things.