Operator and supporters of marijuana dispensaries say banks are turning away their businesses because they risk falling afoul of anti-money-laundering and drug-trafficking laws.

Sue Harank, co-owner of Denver-based dispensary Alpine Herbal Wellness, said her accounts were closed in two banks and the credit union, after she opened a shop in March 2010.

Both banks and the credit union pursued our business initially and said they had talked to the corporate office and run it through legal, but a month or two later they all reversed themselves, she said.

The largest U.S. bank, Bank of America Corp, said it started withdrawing services from dispensaries after receiving a warning from the U.S. Drug Enforcement Administration in late 2007 or early 2008.

US marijuana shops struggling for bank services
Sue Harank, co-owner of marijuana dispensary Alpine Herbal Wellness, poses in her shop in Denver with a poster showing different marijuana types June 20, 2011. Marijuana dispensaries in U.S. states that have legalized medical pot are struggling to obtain service from banks and credit-card companies, pressured by federal authorities who consider illegal the business estimated at $1.7 billion annually. "It was a nightmare," Harank said of her efforts to find a bank. The shop opened in March 2010, and during the following six months two banks and a credit union closed her accounts, she said. REUTERS
US marijuana shops struggling for bank services
Richard Lee, founder of Oaksterdam University, is seen among cannabis related retail merchandise in Oakland, California June 30, 2010. Picture taken June 30, 2010. REUTERS
US marijuana shops struggling for bank services
Marijuana buds, including their cost and degree of potency, are shown in a medical marijuana dispensary in Oakland, California June 30, 2010. Picture taken June 30, 2010. REUTERS
US marijuana shops struggling for bank services
A medical marijuana patient places an order at a dispensary in Oakland, California June 30, 2010. REUTERS
US marijuana shops struggling for bank services
A man holds a sign advertising a medical marijuana dispensary on Venice Beach in Los Angeles, California, July 19, 2010. REUTERS
420 Best Mix
This 4/20 music mix is a totally unofficial and hole-fileld list of the best songs about the herb to listen to on Friday. It's mostly hip hop, though there's a reggae mix to die for thrown in for fun. But if you just put them on and take a sunny afternoon drive or lay back on your bed and let the chunes in, you'll be 'laxing in an ear-tickled haze by 4:21 p.m. (or a.m., if you get down like that.) REUTERS
Bank of america U.S. Bank of america