Hawaii may once again be at the nation’s forefront when it comes to setting smoking policy.

The first state to raise the minimum age for purchasing tobacco products to 21 is considering a measure that would effectively forbid cigarettes in five years.

State Rep. Richard Creagan, a medical doctor, sponsored legislation that aims to phase in a ban, raising the age requirement to 30 in 2020, 40 in 2021, 50 in 2022 and 100 in 2024. The bill, likely to be debated in committee this week, would exempt electronic cigarettes, cigars and smokeless tobacco.

Should the measure become law, it could mark the first step toward a more comprehensive prohibition down the road. After Hawaii raised the legal smoking age to 21 in 2016, five other states – California, New Jersey, Massachusetts, Oregon and Maine – raised the legal age to buy cigarettes to 21.

Cigarette-smoking rates have tumbled nationally for years. According to the Centers for Disease Control and Prevention, the figure sank from 20.9 percent of American adults in 2005 to 15.5 percent in 2016, the latest year for which national figures are available. For those younger than 18, the rate is below 7 percent.

“Because smoking rates are getting so low, we can actually start thinking about what I call end-game strategy, meaning we’re at the point where we can feasibly just make smoking history,’’ said Michael Siegel, a professor at Boston University’s School of Public Health. “We couldn’t even talk about it when there was a large percentage of people smoking because there were too many people affected.’’

Siegel said the five-year target for banishing cigarettes is probably optimistic. Creagan’s ambitious bill may get watered down in the Legislature, and it will probably face opposition from the tobacco industry.

Leading cigarette producer Altria, formerly known as Philip Morris, did not return calls seeking comment.

Siegel pointed to two factors that may pave the wave for cigarette smoking to eventually become a distant memory preserved in film noir movies.

First and foremost is the emergence of e-cigarettes – also known as vapes, mods, ENDS (electronic delivery nicotine systems) or the brand name Juul.

Though unsafe for youths and highly addictive in general because of their nicotine content, e-cigarettes have nowhere near the 7,000 chemicals found in the smoke from regular cigarettes. For adults who smoke, they are regarded as a much safer option.

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The other key development has been the evolution of the tobacco industry, which doesn’t wield nearly as much political clout as it did in past years.

Battered for years by campaigns that highlighted the deadly nature of its products, Big Tobacco had to adapt, and it found a useful vehicle in e-cigarettes, which derive their nicotine from a type of tobacco plant. In December, Altria bought a 35 percent stake in Juul for $12.8 billion.

“The tobacco industry itself is preparing for this," Siegel said. “They see this coming, and they are already diversifying. The cigarette companies themselves are talking about shifting from combustible nicotine to other forms of nicotine."

Even though Hawaii ranks toward the lower end nationally in smoking rates, Creagan said he introduced his legislation because taxes and regulations were not effective enough in keeping people from lighting up.

He wants the Aloha State to be the first in the country to ban cigarettes entirely. He countered charges of governmental overreach by saying the state is obligated to protect its citizens from dangerous products.

“In my view, you are taking people who are enslaved from a horrific addiction and freeing people from horrific enslavement," Creagan told the Hawaii Tribune-Herald. “We, as legislators, have a duty to do things to save people’s lives. If we don’t ban cigarettes, we are killing people.”

Lynn Kozlowski, an expert in tobacco policy who teaches at the State University of New York at Buffalo, questioned whether legislation is the right approach in further snuffing out smoking habits.

He said he approves of exempting e-cigarettes and smokeless tobacco because they provide less harmful alternatives to smoking, but cigars don’t quite fit into that category, at least not when their smoke is inhaled.

Kozlowski said history has shown forbidding access is not the most effective way of modifying adult behavior. He’s wary a black market for cigarettes may develop if they’re banned.

“If you can use ways to make the public fully aware of how dangerous cigarettes are, understand the differential risks, differentially tax these products, that’s been shown to have an effect on bringing smoking down," Kozlowski said. “A ban is not a tool I would turn to at this time."