The governors of Washington and Colorado are urging federal officials to speed up rules to give the recreational-pot industry access to banking services.

In a joint letter, Gov. Jay Inslee and Colorado Gov. John Hickenlooper said without banking services marijuana businesses will be exposed to “significant risks of criminal activity associated with accepting, storing and transporting large quantities of cash” related to pot sales.

The governors’ letter follows an earlier one sent in October asking federal banking officials to allow state-licensed recreational-pot businesses access to the banking system.

Although federal officials in February issued guidelines for banks and credit unions who want to handle money from marijuana sales, Inslee and Hickenlooper said “follow-up interagency guidance to both examiners and depositary institutions” is needed.

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Banking officials have said the guidance from the Department of Justice and the Treasury Department hasn’t relieved concerns they could be prosecuted or sanctioned for serving an industry whose product is illegal under federal law.

The Colorado Bankers Association told NBC News at that time the federal guidelines were “a red light.” The association’s senior vice president, Jenifer Waller, said the government outlined “all the risks involved of banking the marijuana industry” and “made it very clear that financial institutions can still face criminal liability.”

Karen Thomas, senior executive vice president for government relations and public policy at the Independent Community Bankers of America, told NBC that most of its members still feel it’s too risky.

She added another stumbling block was that the guidelines require a lot of paperwork to satisfy federal regulators and prosecutors.