Under the Controlled Substance Act of 1970, however, marijuana is still classified as a Schedule I substance, making it illegal at the federal level. Amid contradictory directives at the state and federal levels, many workers’ compensation payers are choosing to categorically deny coverage.

They’re within legal and medical parameters to do so, because medical marijuana is not currently included in any workers' comp treatment guidelines — such as the Official Disability Guidelines and the American College of Occupational & Environmental Medicine practices guidelines — which are considered the gold standards for treatment of occupational injuries.

Related: Using worker's compensation insurance to help employee health and safety

As such, the future of medical marijuana in workers' comp remains unclear. Consider the latest pros and cons surrounding the issue:

In this Jan. 5, 2016, file photo, packaging for medical marijuana is displayed at Vireo Health of New York, a dispensary in White Plains, N.Y. (Photo: Jennifer Peltz/AP Photo)

Pro: Potential alternative for pain management

There is significant interest in using medical marijuana as an alternative to opiates for the management of chronic pain. In June 2015, the “Journal of the American Medical Association” reported that existing clinical trials showed medical marijuana effectively treats chronic and neuropathic (nerve) pain. However, large-scale, randomized studies are still required to confirm these results.

Con: Workplace risks

In states that have legalized medical or recreational marijuana, workplace safety is a concern.

Employers have a responsibility to foster an environment devoid of recognizable hazards that could cause harm or death.

If a company employs a medical marijuana user, this person might experience side effects, such as impaired cognition, balance and coordination or decreased alertness and delayed reaction time — all of which could result in workplace injuries. Use of cannabidiol would deliver some of the alleged medical benefits while significantly reducing intoxication. But some side effects might still be experienced. More research is needed in this area.

Related: More workers testing positive for drugs

Brandon Coats, a quadriplegic medical marijuana patient who was fired by the Dish Network after failing a drug test, right, waits for the proceedings to begin with his mother, Donna Scharfenberg, at the Colorado Supreme Court in Denver on Sept. 30, 2014. Coats’ case highlights the clash between state laws that are increasingly accepting of marijuana use and employers’ drug-free policies. (Photo: Kathryn Scott Osler/The Denver Post via AP Photo)

Pro: Current use of medical marijuana in workers' comp

The New Mexico Court of Appeals ruled three times since May 2014 that medical marijuana was “reasonable and necessary” for injured workers and had to be covered under workers' compensation.

In these cases, injured employees were authorized to use medical marijuana after traditional therapies failed to relieve their pain. The respective employers were ordered to reimburse the injured workers for medical marijuana, and the reimbursement process enabled the insurer to avoid directly paying for marijuana as it’s still an illegal substance.

Con: Drug-free workplace policies

Because marijuana continues to be categorized as a Schedule I substance, there are ramifications regarding drug-free workplace policies. For example, employees could be authorized to use medical marijuana but still be terminated if they tested positive for marijuana in a random drug test. Ironically, New Mexico — a state that has deemed medical marijuana to be compensable under workers' compensation — has seen such a decision.

Tractor Supply, a New Mexico employer, fired a new hire for using medical marijuana, as it went against the company’s drug-free workplace policy. A federal court upheld the employer’s termination in this situation. If the court had sided with the employee, Tractor Supply, which has stores in 49 states, would have had to modify its drug-free policy for each state that has legalized medical marijuana.

The Garcia v. Tractor Supply decision mirrors one made by the Colorado Supreme Court in June 2015. In Brandon Coats v. Dish Network LLC, the court affirmed Dish Network’s termination of an employee for smoking marijuana outside of work, even though the employee was legally registered under Colorado law to use medical marijuana.

Related: Congress still denies vets access to medical marijuana

In this photo taken May 2, 2014, Kari Boiter, of Tacoma, Wash., poses for a photo at Rainier Xpress, a medical marijuana dispensary in Olympia, Wash. Boiter says marijuana replaced prescription drugs such as steroids and antidepressants that were nearly ineffective for her. More states allow the medical use of marijuana, but major insurers still don’t cover its cost. (Photo: Ted S. Warren/AP Photo)

Pro: Pending legislation at the federal level

The Compassionate Access, Research Expansion and Respect States Act is currently stalled in the U.S. Senate Judiciary Committee. If passed, this act would recognize that states have the responsibility to set marijuana policy. It would also reclassify marijuana from a Schedule I to Schedule II substance, acknowledging that it has “Accepted Medical Use.”

Con: New Mexico rethinks reimbursement

New Mexico previously demonstrated considerable support for medical marijuana, and it continues to be at the center of this controversy. In November 2015, it became the first state to pass a reimbursement rule for medical marijuana. Under this rule, workers' compensation claimants could be reimbursed up to $12.02 per gram of marijuana for up to 226.8 grams per year.

However, in November 2016 — just a year after the initial reimbursement rule was proposed — the state is now putting forward a bill that says workers' compensation insurers and employers would not be liable to reimburse injured workers for medical marijuana. The bill is still under consideration, but it would bring the state in line with recent federal court decisions that have allowed employers to fire employees for medical marijuana use.

Related: Pro-pot votes could set up a showdown with Trump

In this Dec. 4, 2015 photo, books about marijuana lay on a table in the office of University of Vermont pharmacology professor Wolfgang Dostmann in Burlington, Vt. The university has one of the first accredited academic programs in the country to offer a pharmacology class on medical cannabis. Professors said they are hampered by a lack of research on the topic. (Photo: Lisa Rathke/AP Photo)

Pro: Obama administration broadens research

In August 2016, the Drug Enforcement Administration was asked to reassess marijuana’s classification.

Although the DEA decided to retain its current categorization, the Obama administration said it would be easier for researchers to study marijuana’s medical benefits by expanding the number of entities that can apply to legally grow marijuana for research purposes.

Currently, only researchers at the University of Mississippi are allowed this privilege, as part of a contract with the National Institute on Drug Abuse. Researchers will need approval from federal agencies, such as the DEA and Food and Drug Administration, to conduct studies of marijuana. However, this decision is a major step toward removing barriers to clinical research that could ultimately provide the scientific information needed to support reclassification.

CON: Too early to tell what Trump administration would do

It’s too early to anticipate what President-elect Donald Trump’s official policies will be in regards to medical marijuana, but while he was on the campaign trail, he said he was in favor of rescheduling marijuana from its current illicit status as a Schedule I substance to Schedule II.

Related: Pot not a gateway to opioids, YouGov survey says

Ongoing changes ahead

The pros and cons outlined here are among a few of the most recent developments related to the use of medical marijuana in workers' compensation.

Nationwide, new legislation and court decisions are continuing to develop, which will affect workers' comp treatment decisions. The discrepancy between state and federal law, particularly in regard to drug-free workplace policies, will need to be resolved.

In the meantime, workers' comp professionals should continue to monitor new bills and judgments — as well as public sentiment and political trends — that will have ongoing ramifications for the industry and could forecast a tipping point toward reclassification.

Kevin Glennon, RN, is vice president of clinical programs at Jacksonville, Florida-based claims management company One Call Care Management. Email him at [email protected].