DENVER (AP) -- When Tim Cullen was opening his first marijuana business four years ago, the high school biology teacher turned pot entrepreneur struggled to get resumes and references from job applicants. "Everyone's experience was on the black market," Cullen said. Now, he said, "it's come out of the closet." Out of the closet, down the street and around the corner. That's where the line of hopefuls stretched Thursday outside a central Denver office building that was hosting a marijuana industry job fair. Cullen, who owns two retail marijuana shops and is a partner in a company that makes hash oil and another that makes vaporizers, was among representatives from about a dozen businesses reviewing applications. O.penVAPE, Cullen's vaporizers company, organized the fair to meet its own growing staffing needs and help others in the industry, said company spokesman Todd Mitchem. Voters in Colorado and Washington approved sales of marijuana for recreational use in 2012, and recreational sales began first in Colorado, in January. This week, in the world's first such accounting, the Colorado Department of Revenue reported the state made roughly $2 million in marijuana taxes in January; that is expected to grow as more retailers are licensed. Among the employers at Thursday's job fair was a tour company looking for guides to help pot tourists navigate Colorado's newest industry. Hemp Temps, a specialist staffing agency, and Medicine Man, a dispensary, were also hunting for candidates. Job descriptions included bud tender, sales representative and web designer. Organizers said they had heard beforehand from more than 600 jobseekers who planned to attend. Mitchem said the company may need a bigger venue for the next fair, which he said is already in the works. Ian Howe, among the jobseekers in line on Thursday, said he was a graduate of the Culinary Institute of America in New York, and hoped to find work with a company that infuses marijuana into foods, or try his hand at growing marijuana. Howe, 23, said he moved to Colorado just 3 1/2 weeks ago, and found the state a good fit. "I've always been an outdoorsy guy, and I've always liked to smoke weed," he said. Near Howe in line, Michael Rubens and Tim Miller chatted about what they hoped to get out of the fair. Rubens said he wanted to find a business that might want to exploit his ideas for marijuana ice cream. Miller said he was an IT financial specialist who could offer the marijuana industry expertise on banking. The federal government earlier this year issued guidance for banks that at least recognizes that many operate in states where marijuana sales are legal. It did not, however, clarify how banks can do business with pot shops and stay on the right side of federal law, which outlaws the drug. At the fair, Miller and Rubens compared notes about job hunting. Miller had 15 resumes in his briefcase. Rubens said with a laugh that he had "20 -- I'm more prepared."