Half the states and the District of Columbia have passed laws legalizing the use of marijuana for medical purposes, but the plant remains an illegal, Schedule I drug on the federal level. Five years after the governors of Rhode Island and Washington petitioned the Drug Enforcement Administration to reconsider this classification, the DEA has denied their requests.

Then-governors Lincoln Chafee (RI) and Christine Gregoire (WA) filed petitions with the DEA in Nov. 2011, calling for the agency to begin the process of repealing the rules that had placed marijuana on the list of Schedule I controlled substances alongside heroin and other drugs deemed to have no legitimate medical use.

That means marijuana is technically more restricted that opioid painkillers, cocaine, and methamphetamine — all of which are currently classified as Schedule II drugs that the government believes may have proven medical uses.

The petitions sought to reclassify marijuana as a Schedule II drug, arguing that cannabis does indeed have an accepted medical use, that it is safe for use under medical supervision, and that it has a relatively low abuse potential compared to other Schedule II drugs.

In 2013, the DEA asked the Dept. of Health & Human Services to research these issues regarding marijuana, and HHS ultimately recommended that it remain a Schedule I drug.

HHS investigators concluded that marijuana has a high potential for abuse. Then again, so do the drugs on the Schedule II list. You don’t see (legitimate) headlines about a “marijuana abuse epidemic” sweeping the nation like you do about overused painkillers or amphetamines.

However, HHS also said that marijuana’s medical utility is not yet proven. “[T]he drug’s chemistry is not known and reproducible,” reads the DEA denial [PDF] of the petitions, “there are no adequate safety studies; there are no adequate and well-controlled studies proving efficacy; the drug is not accepted by qualified experts; and the scientific evidence is not widely available.”

Of course, part of the reason there is a lack of quality peer-reviewed research on marijuana is that it’s a Schedule I drug and researchers have limited legal access to the very drug they need to test.

Federal agencies “can stop a research project in its tracks,” J. Michael Bostwick, a psychiatrist at the Mayo Clinic who has studied the history of marijuana’s use, recently told our colleagues at Consumer Reports.

To that end, the DEA has released new guidance [PDF] intended to address this alleged lack of credible science on marijuana.

“Although no drug product made from marijuana has yet been shown to be safe and effective in such clinical trials, DEA – along with the Food and Drug Administration (FDA) and the National Institutes of Health (NIH) – fully supports expanding research into the potential medical utility of marijuana and its chemical constituents,” reads the document.

The DEA notes that it can do nothing about the funding of marijuana research, but it can make it less difficult for researchers to obtain marijuana for testing.

Right now — and for the last half century — there has only been one marijuana grower in the U.S. authorized and contracted by the federal government to produce plants for research purposes. The DEA says research demand was, for the longest time, quite limited.

“However, in recent years, there has been greater public interest in expanding marijuana-related research,” notes the document, “particularly with regard to certain chemical constituents in the plant known as cannabinoids,” referring to the active chemicals unique to the marijuana plant.

Certain cannabinoids have been linked to possible legitimate medical uses, like treating seizures and neurological disorders. Thus, researchers have been asking the government for marijuana strains that have varying concentrations of these chemicals; that’s not the easiest thing to do when you have just one grower.

So the DEA says the “best way to satisfy the current researcher demand for a variety of strains of marijuana and cannabinoid extracts is to increase the number of federally authorized marijuana growers.”

This does not open the floodgates to every commercial pot grower to start growing plants for researchers. Potential plant sources must go through an application process and even then the DEA notes that regulations only allow the government to register enough growers to “produce an adequate and uninterrupted supply of these substances under adequately competitive conditions for legitimate medical, scientific, research, and industrial purposes.”

Applicants will also face increased scrutiny if they have any criminal history in their background. It’s not an automatic “no,” but the DEA notes that previous violations of the law “may weigh heavily against granting the registration.”

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