Many employers have policies prohibiting the possession or use of any illegal substances, including marijuana, in the workplace. However, an employer is required to accommodate an employee's disability to the point of undue hardship. An employee may claim that they have a disability that requires they treat it with medical marijuana. The duty to accommodate is a general and ongoing duty that arises once a prima facie case of discrimination has been established: Once a prima facie case of discrimination is established, the next question becomes whether a policy prohibiting the use or possession of marijuana in the workplace is a bona fide operational requirement (BFOR); this is determined on a case-by-case basis in accordance with the standard legal analysis established by the Supreme Court of Canada in British Columbia (Public Service Employee Relations Commission) v. B.C.G.E.U. Published in Illness and Disability in the Workplace (December 2015) by Carswell.