SAN FRANCISCO (AP) — Lawyers and pot dealers have long intersected in criminal court, but as marijuana goes mainstream, attorneys have been working to keep sellers and growers legit. Marijuana divisions are popping up at law firms to advise pot shops on where they can locate, what their websites can say and how to vet new clients. "It's definitely something that established firms are dipping a toe into, though they are being very cautious, and rightly so," said Sam Kamin, a professor at the University of Denver Sturm College of Law who teaches a class about representing the marijuana industry. Kamin said the firms see marijuana as a lucrative new industry, but still worry about the potential ethical and legal pitfalls — and how it will affect their reputations. Marijuana has become a multi-billion-dollar industry.Read more on NewsOK.com