The only federally-approved fields of marijuana in the United States are currently located on the U.S. government’s 12-acre marijuana farm at the University of Mississippi, which has supplied researchers with the drug since 1968. But a new contract to name the official operator of the farm, who will be tasked with growing pot for all the researchers who want to study it over the next five years, will be announced by the end of March. The government's exclusive contract with the University of Mississippi to grow legal cannabis expires on Sunday, and the National Institute on Drug Abuse could choose to move the farm elsewhere.

So far, the University of Mississippi’s contract has been renewed every five years since it was first awarded and it’s likely that this will happen again. However, many changes have occurred in the past five years on the marijuana front. The university's bid could face competition from commercial growers who have set up shop in Colorado and Washington or from researchers at other institutions where interest in studying marijuana's effects has exploded.

Further copmlicating matters, three U.S. senators introduced a bill Tuesdaythat would require NIDA to start no less than two additional marijuana-producing facilities in order to improve researchers' access to the drug. For the time being, though, the current farm is the only one that resarchers can count on. NIDA has told International Business Times that it expects to issue a decision about its location by the end of the month.

“If you ask me, my personal opinion is that we should be the ones to get it because we have the experience, the know-how and the track record,” says Dr. Mahmoud ElSohly, a researcher who has directed the operations of the marijuana farm at the University of Mississippi since the 1980s.  “I assume we will be the ones, but I can’t be sure."

The University of Massachusetts-Amherst attempted to earn rights to grow marijuana for the government in 2007 but was denied, and researchers there did not plan to submit a bid in this latest round, as reported by U.S. News and World Report

Last year, the farm’s operators were busier than ever because the Drug Enforcement Administration granted permission to NIDA to produce 1,500 pounds of marijuana, a sizeable increase from the agency's previously established limit of 50 pounds. NIDA’s request to produce more weed came as a result of researchers’ growing interest in studying it, particularly for possible medical benefits, according to a statement by NIDA. ElSohly says that samples that were high in a compound known as CBD have been particularly popular lately following anecdotal evidence that it works in treating severe forms of epilepsy in children.

ElSohly estimates that about 20 groups originally expressed interest in submitting a bid for the farm, but doesn’t know how many followed through with a complete application. NIDA would not release the number or names of any groups that had sent in a bid.

NIDA originally issued a request for proposals in August that outlined the operator’s duties. They include growing and harvesting marijuana; creating samples with varying levels of CBD and THC, the compound that causes the feeling of being high; analyzing the potency of marijuana gathered during drug seizures by the DEA; mailing samples to qualified researchers ; and, of course, rolling joints. Some of these samples come as tightly-rolled joints that researchers can burn in order to measure properties related to toxicity. The agency is looking for facilities that boast 12 acres of fields and a 1,000-square-foot indoor growroom that can control light, temperature, carbon dioxide and humidity. The facility must also have a storage vault and security cameras around the premises.

The farm exists because marijuana is a controlled substance, currently listed as a Schedule I drug. That places tight restrictions on who can use it for scientific research and NIDA is partly responsible for deciding which researchers may obtain samples. Critics have said that NIDA’s studies have been too narrowly focused on addiction and abuse, but the agency points out that it has also funded 30 studies in recent years on possible therapeutic benefits of marijuana.

The senate bill introduced on Tuesday would also move marijuana from a Schedule I to Schedule II drug. Medical marijuana is currently legal in 23 states and recreational marijuana is now legal in Colorado, Washington and Alaska, and was passed a legalization referendum from voters in Oregon and Washington, D.C.