The U.S. government has opened a new line of business for America’s biggest banks, and for once they don’t want it. Little wonder: it’s cash from legalized marijuana.

The financial-crimes arm of the Treasury Department is making it easier to deposit the fledgling industry’s growing revenue, at last count nearly $3 billion annually and almost all in cash. The government wants to tax the revenue and keep it away from organized crime. And it figures banks with strong compliance departments can best help it track the money.

At the same time, federal bank regulators have remained silent on the issue, raising the specter that banks could run afoul of federal drug laws if they accept the cash. That’s left the banking industry dazed and confused about what to do even as legal marijuana sellers in 23 states and the District of Columbia are faced with mountains of cash piling up in warehouses and basement vaults.

“More than 200 million Americans live in states where there is some form of legal marijuana,” said U.S. Representative Earl Blumenauer, an Oregon Democrat, who is pushing a bill on marijuana taxation. “It’s a disservice to these business people to deny them normal access to banking services.” [Read more at Insurance Journal]