Colorado is fast becoming the place to be for America’s potheads, with more than five million dollars worth of weed sold last week.

Since sales of recreational marijuana began on January 1, traffic has been booming at the state’s 50 or so cannabis shops that are currently operating.

But as dope remains banned by federal law, many pot shops can’t officially get bank accounts to deal with huge amounts of cash, a problem insiders expect will soon have to change.

Attorney Jessica Peck, co-founder of the Women’s Marijuana Movement said: “We’ve seen just recently that the federal government, through the Obama administration, has given what the Denver Post referred to as a ‘yellow light’ – meaning, look, we’re going to open the door to some sort of legitimized banking, but don’t abuse it. Let’s work on this together.”

A handful of stores have even reported running out of stock, which is available to anyone aged 21 or over.

The Women’s Marijuana movement says it expects 1 in 4 residents in Colorado will be using the drug over the next year.

Meanwhile some medical officials say the easy access to the drug in Colorado poses health risks, especially to young people.

Christian Thurstone, medical director of the adolescent substance abuse program at Denver Health, says adolescent exposure to marijuana can significantly change brain development.