Marijuana plants flourish under the lights at a grow house in Denver. (Ed Andrieski/AP)

Vermont Gov. Phil Scott (R) signed a bill Monday legalizing the possession and consumption of marijuana for recreational use in his state.

Scott's signature makes Vermont the first state to approve recreational marijuana legislatively. Eight other states plus the District of Columbia have passed marijuana legalization measures via ballot initiative. Nationwide, 70 million people — more than 1 in 5 Americans — now live in legal marijuana states.

“I personally believe that what adults do behind closed doors and on private property is their choice, so long as it does not negatively impact the health and safety of others, especially children,” Scott said in a statement, adding that he signed the bill with “mixed emotions.”

Unlike bills passed by voters in the other eight states, the law in Vermont does not allow for a commercial marijuana industry to be established there. Individuals may possess up to an ounce of marijuana for personal consumption and grow up to six plants, but buying and selling the drug remains prohibited.

This is the Vermont state legislature's second attempt to legalize marijuana for adult use. In 2017, the state legislature passed a similar bill that Scott vetoed, citing weak penalties for the sale of marijuana to minors and a need for more time to study other regulatory systems. The governor expressed a willingness to compromise and reconsider his position in early 2018 if his concerns were met.

Public health experts say the lack of a commercial market could be a good thing. Beau Kilmer, co-director of the Rand Corp.'s Drug Policy Research Center, said that Vermont's law will “reduce adult marijuana arrests and prosecutions without creating a commercial model that promotes consumption.”

While marijuana is generally regarded as less harmful than other drugs such as alcohol or opioids, its use does bring a number of health risks, including addiction, cognitive impairment and complications with pregnancy. Opponents of legalization have contended that the commercialization of marijuana will lead to more widespread use of the drug and hence be harmful to public health.

But Vermont's bill largely sidesteps those concerns. There will be no retail sales in Vermont. No advertising. No industry looking for profits.

While the debate around legalization is often framed as a stark choice between drug war-era prohibition and Colorado-style commercialization, Vermont demonstrates the range of policy options in between. Kilmer and his colleagues at Rand outlined a number of them in a 218-page report prepared for Vermont lawmakers in 2015.

Allowing adults to grow and consume their own pot, as Vermont has done, is one of the more restrictive options along the policy spectrum. Between the Vermont and Colorado models there are numerous shades of legalization, from allowing the plant to be grown only by nonprofit co-ops to granting the government a monopoly on marijuana sales.

Each approach brings different trade-offs with respect to public health. Vermont's law ensures that for now, there will be no commercial marijuana industry in the state. But on the flip side, Kilmer says, “the product will neither be tested for pesticides nor potency, and this approach will not generate tax revenue from cannabis sales.”

Regardless of state law, marijuana remains illegal for all uses at the federal level. That fact was emphasized this month when Attorney General Jeff Sessions announced the rollback of long-standing federal protections for state-legal marijuana operations.

But the Sessions announcement highlights another advantage of Vermont's approach to legalization: With no large-scale growers or retailers, the state will not offer much in the way of enforcement targets for zealous federal prosecutors. Given the limited amount of resources available for anti-drug efforts, it doesn't seem likely that federal authorities will be interested in Vermonters growing six pot plants in their yard when a full-fledged commercial industry is being set up across the border in Massachusetts.

Vermont isn't the only state looking to legalize marijuana this year. The New Hampshire House of Representatives recently approved a legalization measure similar to Vermont's. New Jersey's incoming governor has vowed to make legalization a 100-day priority. Supporters are hoping to put legalization initiatives on the ballot this fall in Michigan, Arizona, Florida, Missouri and North Dakota.