State laws permitting the lawful use of marijuana for medical or recreational purposes continue to complicate employer efforts to craft policies concerning employees’ marijuana use. Employers know that employees who work under the influence of drugs or alcohol can cause significant safety problems, reduce productivity, and impact workplace morale. Most employers, therefore, prohibit employees from working while under such influence and fire employees who violate these policies. But off-duty use of drugs and alcohol can also create significant problems in the workplace. Consequently, many employers, encouraged or mandated by some state and federal laws and the requirements of certain government contracts, require job applicants to pass a pre-employment drug test. The typical pre-employment drug test detects metabolites of five types of drugs: amphetamines, cocaine, opiates, phencyclidine, and THC (the active ingredient in marijuana). This last category has recently been giving employers particular legal difficulty.

The patchwork of contradictory laws related to the use of marijuana in the United States presents employers with an increasing number of thorny scenarios regarding policies for job applicants or employees who test positive for marijuana. Forty-four states now allow some form of medical marijuana, and several more, led by Colorado and Massachusetts, have legalized the recreational use of marijuana. Many of these state laws prohibit employers from discriminating against job applicants on the basis of the employee’s status as a medical marijuana user.

Under the federal Controlled Substances Act, however, marijuana is classified as a “Schedule 1” drug, meaning that federal law views it as highly addictive, with no medical value. Certain federally controlled licenses – such as a commercial driver’s license – prohibit the use of marijuana and require periodic testing. Most federal contracts require contractors to implement and maintain drug-free workplaces and prohibit the use of marijuana by employees.

Trial courts in both Connecticut and Rhode Island have recently held that despite federal law, an employer violates state law when it refuses to hire an employee who fails a marijuana test but is eligible for medical marijuana under state law. Courts in other states with medical marijuana laws have interpreted their laws differently, leaving employers with more discretion. While the federal Americans with Disabilities Act (ADA) does not require tolerance of medical marijuana use as a reasonable accommodation, several state agencies and courts have held that the state law equivalent of the ADA requires a reasonable accommodation of medical marijuana use in many circumstances.

Employers that operate in more than one state, particularly in industries that involve significant federal funding, can very easily get themselves entangled in legal difficulties. To avoid such problems and to attract and maintain a healthy and productive workforce, employers should develop, implement, and update a comprehensive policy related to drug use in general and marijuana in particular.

Every policy should start with an absolute prohibition against being under the influence of drugs or alcohol while on the job. For pre-employment testing for marijuana, however, an employer should tailor a policy to its particular needs, follow that policy, and periodically review and update the policy to make sure that it reflects the employer’s operational and legal needs. The policy should consider each of the following factors.

1. Understand What a Test Reveals and Does Not Reveal: Current urinalysis tests for marijuana do not identify whether an individual is currently under the influence of the drug. While the high from smoking or ingesting marijuana lasts two to six hours, the THC metabolites can be detected in a person’s urine for weeks after use. Someone who uses marijuana on a Friday evening will almost certainly test positive for THC metabolites the following Monday, but the individual will not still be feeling the influence of the marijuana. Employers should understand the limits of the test as they determine what testing program best fits their particular needs.

2. Is the Employer Required to Test for Marijuana by Any Law or Government Contract? Pursuant to federal law, certain positions, such as safety-sensitive positions in nuclear plants or drivers of commercial vehicles over 10,000 pounds, require that the individuals in those jobs test negative for marijuana. Some government contracts may also require the contractor to test for marijuana and prohibit employing anyone who tests positive. If that is the case, then the employer should follow such requirements.

3. Does Off-Duty Marijuana Use Pose a Safety Risk in the Particular Job in Question? As noted, a urinalysis test does not detect whether a person is high, just whether the individual has used marijuana in the days or weeks before the test. Some studies show that high levels of THC metabolites can have long-term ill effects. An employer should carefully consider whether an employee’s off-duty use of marijuana could pose a safety risk for a particular job.

4. Positions That Do Not Fit the Above Categories: If a marijuana test is not required by law or contract, and the employer cannot articulate a well-reasoned safety purpose or other rationale for a pre-employment marijuana drug test, the employer should consider whether it wants to test for marijuana before hiring a job applicant. If not, the employer can simply make the arrangements with the drug testing company to not perform, or not report the results of, a scan for THC metabolites.

5. Consider Medical Marijuana Exceptions: Even if an individual is allowed to use medical marijuana under the law of the state in which the employer is operating and such use in a certain job position is not expressly prohibited by law or a government contract, the employer should establish a policy of individually evaluating whether marijuana usage should prevent the employee from working in a particular position. An across-the-board prohibition is much more likely to get an employer in trouble than an individually considered decision that can be defended on its individual merits.

There is no one-size-fits-all policy that employers can effectively adopt. Different industries and different companies within an industry will come to different conclusions. But employers that do not think through a marijuana-use policy in these changing times are far more likely to face an expensive and distracting lawsuit.