The Justice Department under Attorney General Jeff Sessions blocked the Drug Enforcement Administration (DEA) from taking action on two dozen requests to grow cannabis for research.

The DEA began accepting applications for research one year ago with 25 proposals to consider this month. DEA officials said they needed the Justice Department’s permission to move forward, and the department had made no moves to provide it.

University of Massachusetts professor Lyle Craker had been seeking approval to do research into whether other parts of cannabis have medical value for years. He submitted his latest application in February and also supplied additional information in April.

“They need to think about why they are holding this up when there are products that could be used to improve people’s health,” Cracker said. “I think cannabis has some bad effects, but there can be some good and without investigation we really don’t know.”

Acting DEA Administrator Chuck Rosenberg stood by his statements which encouraged the “legitimate research regarding cannabis and its constituent parts,” but declined to lessen restrictions on its classification as a Schedule I controlled substance last year.

The 25 applications to grow cannabis for research had not yet been rejected, but the department is not taking any action at all. Before approval, DEA officials must assess each applicant and determine whether their facility is secure and in compliance with federal law.