State laws governing the sale and use of marijuana have changed dramatically in the last decade, leading to some problems for employers and friction between state and federal laws. As Amy McDougal writes in The Complete Compliance and Ethics Manual (2019):

“No two state laws are the same with respect to what constitutes lawful use of marijuana and what protections are afforded to employees who consume cannabis products. For example, while some states explicitly state that an employer is not required to accommodate the use of medical marijuana, others provide affirmative protection for workers who lawfully use medical marijuana. In addition, at the time of this article eight states and the District of Columbia have legalized recreational marijuana. It is reasonable to expect this number will continue to increase, creating additional concerns for employers who seek to balance a drug-free work environment with the rights of their employees to receive recommended medical treatment or engage in lawful recreational use.”^[1]