Updated

DENVER (AP) — Colorado has enacted statewide regulations for the medical marijuana industry which could potentially allow hundreds of dispensaries to continue operating.

Gov. Bill Ritter on Monday signed two bills passed by lawmakers this session to rein in the estimated 1,100 medical marijuana dispensaries that have cropped up around the state.

Both laws take effect immediately. One allows only doctors in good standing to recommend medical marijuana. The other sets up a uniform set of rules for marijuana dispensaries as well as growers and makers of marijuana-infused snacks preferred by some patients.

Regulators expect only about half of the existing dispensaries to be able to continue operating under the rules.

In his state of the state message in January, Ritter urged the industry to work with communities and law enforcement to come up with compromises that protect the public and patients using medical marijuana.

"The companion measures I signed today strike a delicate balance between protecting public safety and respecting the will of the voters," Ritter said.

The measures face potential legal challenges from supporters who say they go too far, allowing communities like Vail, Aurora, Superior, Arapahoe County and Colorado Springs to clamp down on the industry.

"On the one hand, we are pleased it legitimizes this health care industry; however, we are concerned it may be overly strict and could cut off patient access to medication as a result of the dwindling number of dispensaries," said Brian Vicente, executive director of Sensible Colorado, a medical marijuana patients' group.

Under the new laws, cities and counties are able ban dispensaries within their borders. In places where they're allowed, owners will have to undergo criminal background checks. Dispensaries must grow 70 percent of their marijuana, a provision aimed at keeping tabs on where it is being sold.

Karen O'Keefe, director of state policies for the Marijuana Policy Project, said a state-regulated medical marijuana program is already in effect in New Mexico and similar programs will soon be operational in Rhode Island, Maine, New Jersey and Washington, D.C.

O'Keefe said the number of sanctioned dispensaries to be allowed in each of those states and the District of Columbia is fewer than 10. Colorado's law will authorize hundreds, and potentially more if future demand increases.

Colorado's medical marijuana industry will be overseen by the state revenue department in much the same way that casinos are regulated. Inspectors will investigate the books of marijuana businesses to look for criminal ties.

Fees to be set by regulators will pay for the system, and smaller dispensary owners fear they may not be able to afford them. Some dispensaries will also likely have to merge with growers to meet the requirement that they grow most of their own pot.