It's well known that pot businesses have used digital currency, like bitcoin, to work around the issue of banking and use of credit cards, given that most financial institutions, complying with federal law, will not service green industry folk. But now, in Washington state, even that's under fire.

State Senators Steve Conway and Ann Rivers proposed a bill to prohibit local cannabis businesses from buying or selling products using bitcoin. "A marijuana producer, marijuana processor, or retail outlet must not pay with or accept virtual currency for the purchase or sale of marijuana or any marijuana product," according to the bill, in which "virtual currency" also includes digital currency.

If this bill passes in the Washington State Senate, many businesses may be forced to return to all-cash transactions, making them vulnerable to robbery and poor accounting.