Seattle medical marijuana dispensary co-owner Ryan Kunkel has a problem most people dream of: too much money.

Intimidating stacks of cash, bundled into $1,000 bricks, would look out of place in a typical office. But if you're a pot-dispensary operator in Washington or Colorado, the unusual issue of where to stash your profit is common.

Although some states are welcoming pot businesses, banks are governed by federal banking rules—and under federal law marijuana is still illegal.

With federally insured banks unwilling to accept drug money—even in states where weed has been decriminalized—dispensary owners are closely watching for signs they'll be able to make some regular business deposits.

Attorney General Eric Holder revealed in an interview yesterday that the Treasury is working to address the barrier between marijuana’s state legality and federal banking.

Holder says it is a public safety issue and that these regulations are more about dealing with reality than making accommodations.

“Carrying such large amounts of cash is a terrible risk that freaks me out a bit because there is the fear in my mind that the next car pulling up beside me could be the crew that hijacks us,” Kunkel told The New York Times earlier this month. “So, we have to play this never-ending shell game of different cars, different routes, different dates and different times.”

Legal marijuana sales in the United States may reach $3 billion this year, said Aaron Smith, executive director of the National Cannabis Industry Association in Washington, D.C.

“Banking is the most urgent issue facing the legal cannabis industry today,” Smith said. “So much money floating around outside the banking system is not safe, and it is not in anyone’s interest. Federal law needs to be harmonized with state laws.”

The attorney general's statement came just days after President Barack Obama told The New Yorker in an interview Sunday that he doesn’t think weed “is more dangerous than alcohol."

City and state taxes on legal marijuana could serve as a financial lure—a gateway, even—to national decriminalization. And legal pot's pull is edging closer to Capitol Hill.

D.C. legalized medical marijuana in 2010 and subjected it to a city tax the same year. Now, a marijuana decriminalization bill is set for a vote in the D.C. Council during its Feb. 4 legislative session.