ASPEN, Colo. — Colorado Gov. John Hickenlooper is refusing to call the state's legalization of marijuana a success — mostly because he says that would send a bad message to kids.

"Talk about bad branding," Hickenlooper said during an interview with Yahoo News' Global Anchor Katie Couric at the Aspen Ideas Festival on Tuesday, six months after recreational pot use in the state was legalized. "We don't want kids slipping off the rails."

But the governor, who previously opposed legalization because he saw "so many risks," now readily admits that many of his fears surrounding the topic have gone unrealized: The state has not seen a giant spike in adult consumption or an uptick in pot-impaired drivers, there hasn't been an increase in marijuana trafficking to neighboring states, and while the black market for weed still exists, "it's been damaged."

And Hickenlooper estimates the state will reap between $60 million and $100 million in taxes from the marijuana industry this year, and $130 million in 2015.

Being pleased with the outcome of marijuana legalization in Colorado, however, doesn't mean there isn't room for improvement. "It could've been a lot worse," Hickenlooper said. "But we've got to do better."

Hickenlooper says he believes the rise in use of edible marijuana — which the state did not foresee — is problematic, especially for first-time users.

"The jury's still out on edibles," he said. "A brownie that has 10 doses, people say, 'It's legal, how bad can it be?'"

The state is currently working to "limit each donut, each cookie, to one dose," he added.

Another problem: Because marijuana is still considered illegal by the federal government, banks won't accept money from pot retailers, making the legal marijuana industry an all-cash business.

"If you want to encourage corruption, make sure it's an all-cash business," Hickenlooper said, adding that the state is working to create an entity to address this issue, but it's still 12 to 18 months away.

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More than any other concern surrounding the industry, though, the governor says he's worried about the negative effect that tetrahydrocannabinol, or THC — the active ingredient in marijuana — can have on a young user's brain. So Hickenlooper's office is working on a campaign to warn those under 21 about the unknown risks associated with marijuana use. The slogan? "Don't Be a Lab Rat," replete with fake rats in metal cages posted at bus stops.

The governor dismissed the notion that such a campaign, coupled with legalization, is sending a mixed message to children.

"Kids have been getting a permissive vibe for years," Hickenlooper said.

Legalization, he said, is "one of the great social experiments of this century."

"Let's face it, the war on drugs was a disaster," he added.

Not that he's partaking in legal marijuana himself.

"No," Hickenlooper said. "As people in my office say, 'We don't need help making ourselves a little dumb.'"

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