Medical Marijuana and Employee Drug Testing
Whether or not an employer may legally fire or deprive you of a job opportunity for failing an employee drug test because you used medical marijuana off the job, depends on whether or not your work state has passed a medical marijuana law with employment discrimination protections.
Over half of U.S. states, the District of Columbia, and the U.S. territories of Guam and Puerto Rico have passed so-called medical marijuana laws that, for reasons of compassion, authorize marijuana as a legitimate treatment for certain medical conditions. A few additional states have pending legislation to legalize medical marijuana.
All of the medical marijuana laws prohibit prosecuting state-authorized patients for crimes relating to the use and possession of the drug. However, none of the laws that states have passed so far permit employees to use or possess pot at work, or to come into work stoned.
Only a few of the laws explicitly prohibit employers from discriminating against state-authorized medical marijuana users who are in compliance with the laws. In other words, the laws prohibit employers from firing, refusing to hire or otherwise punishing state-authorized users for failing drug tests due solely to using medical marijuana off the job.
If your employer fires you for using medical marijuana off the job, then your employer might be able to deny you unemployment benefits too. However, you may appeal the denial.
Some of the state medical marijuana laws — including some that have employment discrimination protections — generally allow employers to fire workers or reject job applicants for failing employee drug tests due to medical marijuana use, if not doing so would make the employers lose Federal benefits. That's because marijuana (A.K.A. marihuana and cannabis) is still an illegal drug under Federal law, whether or not it's for medical use.
States are prohibited from legalizing violations of Federal law, which is exactly what state medical marijuana laws do. Subsequently, employers who have solid drug-testing policies in place regarding medical marijuana use might be able to justifiably discriminate against state-authorized users as indicated in the policies, up to and including firing or refusing to hire them for failing employee drug tests.
If your work state has not yet enacted a medical marijuana law, then an employer may fire or refuse to hire you for failing an employee drug test due to using pot off the job. The same goes if your work state has enacted a medical marijuana law, but without providing employment discrimination protections. However, in the latter case, you still might be able to challenge an employer's disciplinary action in a court of law, such as under public policy or a state civil rights law. Talk to a lawyer about that.
Even if you work in a state that has a law with employment discrimination protections, your employer still might fire or otherwise punish you for using medical marijuana off the job. It's not unheard of for employers to violate discrimination protections, either intentionally or in ignorance of the laws that provide them.
If an employer asks you to take a drug test, be sure to present the documents that your doctor and work state gave to you, which authorize your prescription for medical marijuana. Show the documents to both the drug tester and the employer. If the employer fires or refuses to hire you because you failed the drug test, having shown the documents might strengthen your case should you decide to take the employer to court. Talk to a lawyer about filing a lawsuit against an employer.
To see how long the resulting chemical changes (metabolites) stay in your system after using marijuana, refer to Drug Detection Time for Drug Testing in the Workplace.
To see how much of the metabolites it takes to fail a drug test, refer to Workplace Drug Testing Cutoff Levels.
Colorado, Washington, Oregon, Alaska, Delaware and the District of Columbia have passed bills legalizing or decriminalizing the recreational use of weed. (All of those have done the same for using medical weed.) Some of the bills may not have become effective yet.
Update: On 11/3/2015, Ohio voters rejected legalizing marijuana for either medical or recreational use. Voting results were 35% for and 65% against.
Update: The Colorado Supreme Court ruled on 6/15/2015 that employers may fire employees who test positive for using medical marijuana while off duty, even if such employees are not impaired on the job. The Court held that under Colorado's lawful activities statute, the term lawful refers only to activities that are legal under both state and Federal law.