On Wednesday, the Justice Department’s Office of Legal Counsel (OLC) disclosed a memo that seemed to have been used by the Drug Enforcement Administration (DEA) to justify delaying approval of additional marijuana manufacturers for research purposes beyond the sole legal that scientists have had to rely on for half a century. That disclosure was the result of a Freedom of Information Act lawsuit filed by SRI last month.

Attorneys representing SRI said that the newly unveiled document helps explains what was happening behind closed doors for several years of inaction and delays after DEA initially said in 2016 that it would be approving more manufacturers.

But in their new letter to members of Congress, they identify a federal statute that they argue can be used by the attorney general to waive registration requirements, allowing research institutes to immediately grow their own cannabis for studies or to purchase it from licensed dispensaries instead of having to wait until new rigorous licensing rules go into effect.