Employers in Canada are asking themselves how the October legalization of the recreational use of marijuana will affect the workplace in terms of safety and their duty to accommodate an employees use of the drug. Companies are advised to draft an employment policy that address the issue. But first, it is important to understand the obligations an employer has regarding recreational use of marijuana and the differences between this form of its use and for those employees who have a prescription. Employers may still limit the use of the drug in any fashion if the employee appears to be impaired physically or mentally impaired by alcohol, drug or other substance. In a recent case, an arbitrator dismissed an employees claim after he was refected for employment in a safety sensitive role due to his medical marijuana use.