The top law enforcement officials from 38 U.S. states and territories are calling on Congress to pass legislation to increase marijuana businesses’ access to banks. The move comes just days after the treasurers of 17 states issued a separate call in support of the pending cannabis financial services bill.

Even as a growing number of states adopt laws to legalize marijuana for medical or recreational use, federal prohibition remains intact—for now—and that makes many banks wary of maintaining accounts for cannabis growing, processing or retail operations. They could, they fear, be prosecuted under federal money laundering laws.

Legislation to shield financial services providers from being punished by regulators for working with the cannabis industry has been gaining momentum in Congress, and now the effort is getting a boost from the National Association of Attorneys General, which is officially endorsing the bill.

“Businesses are forced to operate on a cash basis. The resulting grey market makes it more difficult to track revenues for taxation and regulatory compliance purposes, contributes to a public safety threat as cash-intensive businesses are often targets for criminal activity, and prevents proper tracking of billions in finances across the nation,” the attorneys general wrote in a letter to congressional leaders on Wednesday.

“[R]regardless of how individual policymakers feel about states permitting the use of medical or recreational marijuana, the reality of the situation requires federal rules that permit a sensible banking regime for legal businesses,” the officials wrote.