Answers: Not for an employer it isnt. They have standards that they inevitability to follow for safety and for the economically being of the company. Its not a issue something like someone doing their job while large, its an issue of lawsuits due to accidents cause by people not surrounded by their right minds. The employer doesnt need you as much as you call for the employer.
No. You have a choice to use drugs, in recent times as an employer has a choice as to what type of soul represents their company. Don't try to claim injustice so that you can validate your desperate choices.