U.S. Treasury Secretary Janet Yellen said on Thursday she would welcome legislation that would rectify the conflict between federal and state laws on the sale and use of marijuana that is preventing cannabis firms from accessing the banking system.

Asked at a U.S. House of Representatives Appropriations subcommittee hearing about the issue, which forces cannabis businesses to hold large amounts of cash, Yellen said: “I think it’s a real problem and it would be desirable to have legislation that alleviated this problem.”

Republican Representative David Joyce said he had raised the same issue with former Treasury Secretary Steven Mnuchin five years ago and little has changed since then.

Some 38 states have approved marijuana for medical use and 24 have approved its recreational use, but cannabis sales remain illegal at the national level.

Most banks, concerned about running afoul of anti-money laundering laws, have shunned the business, forcing cannabis companies to deal in cash, which creates security risks for employees and hampers financing. [Read More @ Reuters]