Colorado has taken steps to stem a growing black market for marijuana since the state legalized recreational use of the drug in 2012. Oregon lawmakers should consider more direct action as well.

Oregon's recreational marijuana industry is newer than Colorado's — voters approved legalization in 2014 — but its medical marijuana system dates back two decades, and its loose regulatory structure has allowed black-market activity to continue.

Colorado is directly funding local enforcement actions against illegal growers, allocating $6 million in marijuana tax revenue to reimburse police departments. Oregon's recreational system allocates 20 percent of pot taxes to local law enforcement, but doesn't specify how the money is spent.

There is no question that marijuana grown in Oregon finds its way to other states where it is still illegal, commanding many times the price growers can get here. An Oregon State Police study obtained by The Oregonian in March found that the production of marijuana in Oregon far outstrips demand, creating a surplus that is worth millions in other states.

Jackson and Josephine counties are among the six biggest producers, the report said, and Medford, Grants Pass, Portland and Eugene are the cities with the greatest connection to black market destinations across the country.

Those findings were based on data collected before the state's seed-to-sale tracking system began to be implemented last fall, and the recreational industry is still taking shape. According to one estimate, a study by Whitney Economics, black market marijuana will account for about 35 percent of the Oregon market this year, down from 53 percent last year and 80 percent in 2014.

That shows legalization is already having the desired effect of putting a damper on illegal exports, but there is still a long way to go.

One obstacle is the role of the Oregon Liquor Control Commission, which is responsible for regulating the recreational market but has no authority to take action against illegal growers. The OLCC investigates illegal liquor sales, but the Legislature did not give it enforcement power under the marijuana law.

Another factor is the tendency of police departments to make marijuana enforcement a lower priority than more serious offenses. And in Josephine County, the sheriff's department cannot even maintain 24-hour patrols, so black-market growers have little to fear.

That could change if the Trump administration's Justice Department decides to crack down on an industry that is still illegal under federal law.

Eventually, the black market will dwindle away as more states opt for legalization, driving prices down and removing the incentive for unscrupulous growers to export their surplus crops for big profits. 

Meanwhile, recreational and medical growers, retailers and dispensary owners who are playing by the book have every reason to support efforts to weed out black-market operators. Allowing the black market to continue threatens the entire industry.