Marijuana is growing on U.S. consumers.

Last week, Illinois became the 11th U.S. state to approve cannabis for recreational adult use, joining a growing cohort that includes California, Vermont and Michigan. The law will go into effect on Jan. 1, 2020.

Now, U.S. cannabis companies like Cresco Labs are undergoing expansion so they're able to produce the supply required to meet the demand in the fifth-largest state in the country, said Charles Bachtell, co-founder and CEO of Cresco.

"You're talking about a state that is going from a relatively conservative medical program — we have about 70,000 patients in it currently — to the fifth-largest state in the country: 13 million people, over 100 million tourists a year, and anybody over the age of 21 are going to have access to the program," he said Thursday on CNBC's "Fast Money."

That represents a 10-to-20-times boost to the current size of Illinois' medical marijuana market, Bachtell said, adding that his company, which operates in 11 states, is equipped to handle it.

"We have the infrastructure in place. We can flip the switch Jan. 1, 2020, as opposed to having to go through an application process," the CEO said.

This legal process can also pave the way for states like New York and New Jersey, which have been weighing broader marijuana legalization, to follow in Illinois' path, Bachtell said.

"That's one of the great things about Illinois pulling this off: first state to ever pass a robust, regulated adult-use cannabis program through the legislature," he said. "I know that the conversations in Albany and likewise in New Jersey lately have been, 'Can you do this?' or 'Does this need to be a ballot initiative?' Illinois has shown them you can do this through the legislature."

Illinois' existing medical marijuana laws also give the state a leg up when it comes to developing the recreational market," Bachtell said.

As opposed to California, which saw lower-than-expected cannabis-tax revenues at the outset because it tried to regulate the industry while opening up the market, "Illinois [has] already changed the way that medical cannabis was done," he said.

"It really created Gen 2 of medical cannabis, which was highly regulated, compliance-focused and these limited licenses. So it's a very controlled program," he said. "We're building on the back of that type of a program. And the legislature did a great job of marrying increased opportunity, increased access [to] points of sale, while at the same time really giving the current operators, the current infrastructure the opportunity to be first to market."

It also helps curb black-market competition, which was part of the reason California saw suppressed tax revenues for the first year of cannabis being legal there, Bachtell said.

"I think we have a great chance of converting a lot of the incumbent illicit market because Illinois doesn't have its own inherent illicit market. That's all imported from out of state," he said. "So, as soon as we get our infrastructure and our adult-use program launched, we give residents in Illinois a great opportunity to participate."

Cresco Labs' stock traded lower on Friday, shedding more than 1%.