Marijuana in the Workplace

Abstract

Marijuana (cannabis) is the most frequently used illicit drug of abuse in the United States and worldwide. Moreover, it is second only to alcohol as the most prevalent psychoactive substance seen in cases of driving under the influence of drugs.1,2 It is also by a wide margin, the drug most often detected in workplace drug-testing programs. The primary psychoactive substance in marijuana is delta-9-tetrahydrocannabinol, known simply as THC. Present in steadily increasing concentrations in street-purchased, smokeable plant material, the THC content in marijuana averaged 3% in the 1980s, but by 2012 it had increased to 12%.3 The US government classifies marijuana as a Schedule I drug (defined as those drugs with no currently accepted medical use and a high potential for abuse,4 and the use/possession of which is subject to prosecution). Workers covered by federal drug-testing programs are uniformly prohibited from using marijuana at any time. In addition, federal law allows employers in every state to prohibit employees from working while under the influence of marijuana and are permitted to discipline employees who violate this prohibition. Nevertheless, with public attitudes toward marijuana use changing, prohibitions for its consumption outside of federal law now vary from state to state. Although the possession and use of marijuana continue to be prohibited by federal law, numerous states and the District of Columbia currently have enacted laws regarding marijuana use that conflict with federal law and policy,5 with legislation pending in other states.6–8 This changing legal environment and the evolving scientific evidence of its effectiveness for treatment of select health conditions require an assessment of the safety of marijuana use by the American workforce. Although studies have suggested that marijuana may be used with reasonable safety in some controlled environments, there are potential workplace consequences involved in its use that warrant scrutiny and concern. The potential consequences of marijuana use in the workplace include the risk and associated cost of adverse events and the loss of productivity. These safety concerns and the changing legal scene have led the American College of Occupational and Environmental Medicine (ACOEM) and the American Association of Occupational Health Nurses (AAOHN) to develop this guidance document to assist occupational health professionals and employers in identifying and addressing impairment issues related to the use of marijuana and prevention of injuries related to impairment. This guidance summarizes current evidence regarding marijuana consumption, discusses possible side effects including temporary impairment as it relates to the workplace, reviews existing federal and state laws and legal implications for health care professionals and employers, and suggests various strategies available to employers for monitoring workers for marijuana use. It is outside the scope of this article to address any potential medical benefit of marijuana. Studies conducted to evaluate the effects of marijuana drug use by workers have demonstrated variable risk. This variability relates to study design, demographics, work type, and potential confounders (eg, general risk-taking behavior among illicit drug users). This discussion on the effects of marijuana is based on a literature search of the currently available evidence (see the Appendix). Articles were graded using the following criteria: inadequate for evidence due to low-quality research; adequate for evidence (+); or high quality (++). High-quality studies, meta-analyses, or multiple adequate studies with the same conclusion qualified as good evidence for the guidance purposes of this document. Statements referring to evidence without a qualifier reflect the results of an adequate study. Other articles are also cited when appropriate to clarify issues that may not have been addressed by studies qualifying as evidence. LEGAL IMPLICATIONS OF MARIJUANA LEGISLATION In late 2009, the US Department of Justice initiated a change in marijuana enforcement policy by issuing a memorandum encouraging federal prosecutors not to prosecute individuals who distribute marijuana for medical purposes in accordance with state law.9 Nevertheless, after voters in Colorado and Washington approved the recreational use of marijuana, the Department of Justice issued another memorandum in August 2013 that reiterated its right to contest the legality of state marijuana laws, stating that the Department "expects states like Colorado and Washington to create strong, state-based enforcement efforts... and will defer the right to challenge their legalization laws at this time."10 This discordance about use, regulation, and legislation places employers in the challenging position of maintaining compliance with divergent and evolving legislation, while continuing to provide a safe workplace. Americans with Disabilities Act The Occupational Health and Safety Act of 1970 contains a general duty clause that requires employers under its jurisdiction to, among other things, maintain conditions or adopt practices reasonably necessary and appropriate to protect workers on the job.11 This duty may necessitate exclusion of those who are impaired or potentially impaired because of marijuana use. As long as marijuana is illegal under federal law, employers who fire or refuse to hire employees for using marijuana are not in violation of the Americans with Disabilities Act (ADA) or any other federal antidiscrimination statute, although there are restrictions on drug testing.12 Nevertheless, some states limit employer action against workers who use marijuana according to state standards. If drug testing is done, the decision to test must be job-related and necessary for business, and conducted when there is evidence of a safety or job performance problem. Currently, the ADA does not require employers to permit marijuana use as a reasonable accommodation for an individual with a disability, even if that person is a registered medical marijuana patient. In some states, court rulings involving the use of marijuana for medical purposes have held that employers are under no obligation to accommodate medical marijuana users, regardless of whether or not its use is permitted by state law.13 The basis of the rulings has been that a person "currently engaging in the illegal use of drugs" is not a "qualified individual with a disability," and marijuana is still an illegal drug for the purposes of federal law. Nevertheless, the ultimate effects of specific state laws on this issue are yet unknown.14 Drug and Alcohol Testing Regulations The majority of private employers across the United States are not necessarily required to drug test, and many state and local governments have statutes that limit or prohibit workplace testing unless required by state or federal regulations due to the nature of the job. Guidance issued by the US Department of Transportation (DOT) for its Drug and Alcohol Testing Regulations state that marijuana use remains unacceptable for any safety-sensitive employee subject to drug testing under DOT regulations.9 This safety-sensitive category includes pilots, bus and truck drivers, locomotive engineers, subway operators, aircraft maintenance personnel, transit fire-armed security personnel, and ship captains, among others.9 Federal agencies conducting drug testing must follow standardized procedures established by the Substance Abuse and Mental Health Services Administration (SAMHSA).15 Private nonunion employers who require drug testing for applicants and/or employees are usually not required to follow SAMHSA's guidelines, but doing so helps to ensure the legality of testing. In unionized workforces, the implementation of testing programs must be negotiated through collective bargaining, even when federal regulations require testing.16 Drug-Free Workplace Act The Drug-Free Workplace Act (DFWA), enacted in 1988 to promote safety and accountability, requires all federal grantees to agree that they will provide drug-free workplaces as a condition of receiving a federal contract of more than $100,000 or a federal grant of any value.17 To qualify and remain eligible for federal funds, these entities are required to make continuous good faith efforts to comply with drug-free workplace requirements. The DFWA does not specifically require drug testing, but it does require that employers (1) publish and distribute a policy statement, (2) specify actions that will be taken against employees who violate the policy, and (3) provide education in the workplace about the dangers of drug use and available counseling and employee assistance programs.9 Employers are not required to fire employees on the basis of the results of a positive drug test. The Act requires employees to abide by the terms of the employer's policy and notify the employer within 5 calendar days if they are convicted of a criminal drug violation in the workplace.9 The contracting or granting agency must be notified within 10 days after receiving notice that a covered employee has been convicted of a criminal drug violation in the workplace.9 Employees who work for federal contractors may be subject to discipline, including termination if marijuana use is proven, regardless of whether its use is permitted by state law.18 Federal Law Enforcement and Transportation of Marijuana Across State Lines Medical marijuana patients are also subject to federal and local charges of transporting marijuana if they cross state lines with the drug, even if they are traveling between states that allow medical marijuana. As the US Transportation Safety Administration enforces federal rules on commercial airlines, transporting marijuana on an airplane is illegal and can lead to federal drug transportation charges.19 Federal agencies may, in some situations, also arrest authorized users. State Laws With so many states and the District of Columbia having enacted medical marijuana laws or decriminalized its use, an employer's legal right to fire or refuse to hire an applicant for failing an employment drug test due to off-the-job medical marijuana use depends on whether the state of employment has passed a medical marijuana law that includes employee discrimination protections. Most states that have legalized medical marijuana do not provide for employee protections, although there are exceptions such as Connecticut, Illinois, Maine, and Rhode Island.20,21 Michigan protects an employee's rights and safeguards against disciplinary action at work for registered patients, except when a worker uses marijuana on site or comes to work impaired. Arizona and Delaware have more explicit statutory language prohibiting an employer from discriminating against a registered qualifying employee who has failed a drug test for marijuana metabolites or components, except if the employee used, possessed, or was impaired by marijuana at the worksite during work hours, or if failure to dismiss an employee who failed a drug test would violate a contract or licensing-related benefit under federal law.20 States that to date have passed laws legalizing recreational marijuana do not provide protections for employee discrimination.22 Colorado presently allows employers to prohibit the use of marijuana at work. Nevertheless, another state law, the lawful off-duty conduct statute, prohibits employers in this at-will employment state from firing employees for engaging in lawful conduct while off-duty and off premises during nonworking hours.23 Conflicting legal decisions have arisen with regard to employees who have been fired for testing positive for marijuana, and as of early 2015, this issue is under review by the Colorado Supreme Court. Until state and federal laws coincide, legal challenges and uncertainty in the workplace will continue.23 Although state laws vary, laws regulating marijuana require employers neither to permit drug use in the workplace nor to tolerate employees who report to work impaired. For this reason, employers may institute drug-free-workplace policies to help ensure that employees come to work in an unimpaired state and do not endanger themselves or others while working. Reconciling varying and dynamic state laws in regard to legality, permitted use in the workplace, and lawful drug testing can be challenging. Every employer should consult with legal advisors to ensure that they comply with any applicable state or local laws and design their testing programs to withstand legal challenges.24 MEDICAL ISSUES Regardless of the legal consequences, the medical implications of marijuana use for the workforce must be considered. In addition to the risk of injury due to impairment, employers must also consider the possibility that increases in absenteeism and presenteeism may occur as marijuana-containing products become increasingly available to workers. In 2007, SAMHSA estimated that 8.4% of full-time workers were engaged in some type of illicit drug use within the preceding month.25 With the legalization of marijuana in certain states, this number could climb. A recent poll found that 9.74% of 534 respondents reported going to work after smoking marijuana (the majority reported obtaining the drug illegally). Although this poll may not reflect the behavior of the US working population as a whole, the data do indicate the need for clear workplace policies addressing workers who use marijuana.26 Metabolism and Impairment When marijuana is smoked, THC blood levels rise immediately because of efficient pulmonary absorption across the alveolar capillary membrane. THC levels fall rapidly after smoking ceases due to distribution of the substance to the brain and lipophilic tissues, as well as hepatic metabolism.27 The subjective "high" and associated impairment begins rapidly as well, within minutes of the initiation of smoking when blood levels are rapidly falling and THC is distributed into the central nervous system. Approximately 10% of the absorbed THC is metabolized by the cytochrome P450 (CYP) enzyme system into the equipotent psychoactive metabolite 11-hydroxy-THC (THC-OH), which appears in the blood soon after the THC peak and then falls off rapidly. The major nonpsychoactive metabolite, THC-COOH or carboxy-THC, appears later and can last for several hours or even much longer in long-term users.28,29 This metabolite is the component commonly assayed in workplace urine drug-testing programs. Impairment periods vary with the dose administered and the route of administration. For smoked marijuana, subjective impairment begins soon after smoking initiation and peaks in about 1 hour and lasts 3 to 4 hours after smoking. Experimental studies suggest that measurable impairment in test subjects lasts approximately 6 hours.27,30,31 Many studies focusing on the duration of impairment after acute use were conducted when marijuana typically had a lower THC concentration. Thus, the applicability of these older study results to today's more potent varieties is questionable as the duration of effect may be longer than previously reported.32,33 Some studies have demonstrated longer impairment (up to 24 to 48 hours) on specific performance measures, but these studies are limited and the few studies showing this effect used small samples.34–36 In addition, no comparison of residual peak performance impairment was associated with situations encountered every day and accepted in the workplace (ie, poor sleep the night before, episodic minor illnesses, the use of cold remedies). As described previously, these residual impairment studies were also conducted when cannabis had a much lower potency than what is available today. It is conceivable that residual impairment may actually be more prolonged and problematic with today's higher potency marijuana. The majority of studies of impairment related to driving and cognition show return to a generally nonimpaired state within 3 to 6 hours after smoking marijuana among occasional recreational users. Impaired behavior from acute use differs between occasional users and long-term users. There is good evidence that chronic frequent marijuana users exhibit less impairment from acute THC than do occasional users, but the degree to which impairment is mitigated in safety-sensitive activities is unclear.37–41 This finding can be likened to the chronic drinker who has less apparent intoxication at a given blood alcohol concentration (BAC) than a naive drinker, yet is still acutely impaired. When marijuana- or THC-containing products are orally ingested, the time to peak blood levels and effects are delayed, with lower peak concentrations and longer duration of effects. Bioavailability varies among marijuana products, owing to the lipophilic nature of THC—products containing more oil or fats tend to increase bioavailability.27 Bioavailability is also impacted by first-pass hepatic metabolism. Edible products do not allow for a titration effect because users cannot immediately gauge the effect of the dose consumed, and acute psychosis, presumably resulting from the higher dose received via the oral route, has been reported.42 The subjective "high" after oral administration usually occurs approximately 30 minutes after consumption. There is some evidence that with doses less than 18 mg, impairment decreases to a level of normal performance around 5 hours postingestion.43 A smaller study of oral ingestion demonstrated impairment of driving skills up to 10 hours after ingestion of higher doses. This impairment did not occur with lower doses.44 In addition, although a state may have regulations regarding the dose of THC to be used in edible products, it is not clear how this is actually being regulated. Thus, consumers may have difficulty controlling the dose they consume in edibles. The subjective "high" from acute marijuana use varies with THC concentration, dose, route of administration, and users' degree of experience with the drug. Common self-described effects are relaxation, euphoria, relaxed inhibitions, sense of well-being, disorientation, altered time and space perception, giddiness, increased appetite, and a more vivid sense of taste, sight, smell, and hearing. Commonly observed central nervous system effects include lack of concentration, impaired learning and memory, alterations in thought formation and expression, drowsiness, and sedation. These psychological effects are accompanied by physiological manifestations of conjunctival injection, a significant increase in heart rate over baseline, dry mouth and throat, increased appetite, and vasodilatation.40 One study found that pupil dilatation, conjunctival injection, and decreased ocular to were the physiological most commonly related to marijuana Some of these physiological are used by drug law enforcement who conduct of Marijuana Impairment Although studies that impairment in the workplace due to marijuana are now to numerous studies using driving and impairment of the skills necessary for safe of a by cannabis use have been much of the regarding impairment and risk in the workplace due to alcohol intoxication has been from studies of driving impairment and these same of studies can be used to impairment in the workplace from studies have been to the level of driving impairment in to the level of THC in or studies of risk associated with cannabis use failed to show significant impairment in cannabis users because some of these studies used the of the as evidence of drug use. In addition, many potentially had blood for THC hours after being and even longer from the of the and of THC from the studies and of studies, including driving and found that and skills related to driving performance were impaired in a with increasing THC blood There is good evidence from a and the following and driving studies that marijuana can of time and and to on from studies of risk have that when marijuana was in they were much more to be at and there was a with having higher THC concentrations being more to be for the Studies have that while using individuals impaired performance in driving and In the driving studies, the were in to and maintain time and and on for a A study of blood levels from more than in an increased for a from for THC less than 1 to for THC 5 or studies have found that with a blood test were 3 to 6 more to be involved in a than without In a study of effects of marijuana, found that any concentration of the psychoactive component was associated with the impairment of the doses was found to with a of THC and blood concentrations more than study that under THC higher than a level of approximately to 5 established impairment, and levels of THC 5 to 10 were of A study found that impaired on blood THC levels higher than nonimpaired drivers, and those with levels of THC more than 3 were at increased risk of being In there is good evidence from a number of studies and a that levels of an of to for oral and to for smoked marijuana impairment approximately to a of around on these a level of 5 of THC can be used as with other medical of acute impairment from marijuana. The metabolite can also be and it may provide regarding impairment. Nevertheless, as the level of THC and to use as a for impairment is not known at this the the need for to levels impairment and to this impairment to chronic users. Employers may to use the of THC and to impairment because is equipotent to THC. users are to experience less acute impairment by some performance measures, and subjective effects at most of these a 5 for allows some for all of users. the between approximately 4 being in effects to a of approximately or using the 5 seen in the impairment studies previously would the current level of alcohol impairment for safety-sensitive workers under federal testing laws (ie, Thus, this may be used to an of the of this THC and level may not acute impairment in an individual This can be only when a medical for impairment has been in with of the which led to the for testing. the basis of the the is a level of THC of 5 to impairment. The that there are several states using higher levels for driving under the influence of drugs (eg, Colorado and Washington use 5 in to approximately 10 in of THC and metabolites as a level for driving under the influence when accompanied by behavior than states address marijuana and of have for any level of It is the of the that a level of 5 should be used to ensure a safe workplace Marijuana Impairment When a worker is of being impaired by marijuana use, and of impairment must be in and become of so that for testing can be This is the same policy as that used for in drug-testing programs. When impairment is employees are for alcohol and urine drug testing. drug testing for marijuana via by testing the THC-COOH metabolite, which can be for after last use, and has no with acute impairment. This testing is for programs and in all marijuana use is illegal or prohibited by the Nevertheless, a urine drug test showing use is not evidence of impairment. Although this use is still prohibited under employment this not be reasonable or in employer drug testing programs in states with legalized recreational use. Employers to prohibit the use of marijuana during time in states it is legal should consult with regarding this of THC metabolites in the urine of recreational users after legal use of marijuana would be to (ie, in the urine of a of these results would indicate acute impairment or violation of a law in states marijuana is For this reason, in states marijuana use, workplace urine drug testing of impaired employees would be Although alcohol can be used to acute alcohol intoxication psychoactive THC cannot be detected in the same and currently requires a blood test. It is suggested that the employee of being impaired be as the employer's suggests that employers include an of the impaired employee at an occupational in The should include a to the or of impairment, a alcohol test, and a urine drug test. To for marijuana, a blood test for the and THC-COOH can evaluate potential acute impairment from cannabis use. The employee should be on these results established If THC THC for employers who to evaluate psychoactive are a level of 5 the employee is acutely impaired by cannabis use. THC levels should be in of impairment by a and/or demonstrated on a medical should also be Testing of oral that may in the as a to whether blood testing is MARIJUANA LEGAL Employees who to be impaired in the workplace should be according to employer levels of THC do not with impairment. levels more all should include an of impairment. The effect of on impairment includes for the route of administration, concentration of and other Employers who to or are required to use of medical and/or recreational marijuana with state law must risk of impairment from marijuana use, for those employees in safety-sensitive The following should be A medical review and other occupational health professionals should be with legal in about policy or individual use of marijuana. regarding testing for and possible impairment should be and to are for these and employees should the implications of the results for their employment based on the policy and for marijuana and other drug use. Most statutes provide when a worker is under the influence of alcohol or illegal drugs