A new federal report provides the strongest argument yet that e-cigarettes are simultaneously safer for adult smokers, but also gateway drugs that could turn teens to conventional cigarettes.

But that doesn't do much to sway Minnesotans such as Lee Kingston. The Cedar, Minn., dad already feels that e-cigarettes weaned him off traditional cigarettes — and he knows he doesn't want his three daughters to use them.

"I would not want them to do anything that could potentially cause them harm," said Kingston, although he considers e-cigarettes less harmful than other vices his children might one day face.

Tuesday's report from the National Academies of Sciences, Engineering and Medicine was a summation of 800 studies of e-cigarettes, which are gaining popularity. An estimated 11 percent of U.S. high school students have in the past month used e-cigarettes — battery-operated heating elements that convert cartridges of liquids containing nicotine into inhaled vapor.

The report had something for everyone in the e-cigarette debate to love. And hate.

"E-cigarettes cannot be simply categorized as either beneficial or harmful," said David Eaton, a University of Washington academic who led the committee that wrote the report. "In some circumstances, such as their use by nonsmoking adolescents and young adults, their adverse effects clearly warrant concern. In other cases, such as when adult smokers use them to quit smoking, they offer an opportunity to reduce smoking-related illness."

Users of e-cigarettes celebrated the report's finding of their products as containing fewer cancer-causing materials than regular cigarettes.

Opposition "has been fueled by so much misinformation," said Craig Schutte, a 53-year-old limo driver who credits e-cigarettes for helping him quit tobacco. "I want to know the truth and I want everybody to know the truth. So I welcome this kind of scrutiny."

The report stopped short of declaring e-cigarettes safe, noting there are no long-term studies of the devices' addictive potential or effects on the heart, lungs or on reproduction.

Smoking cessation advocates welcomed the report's affirmation that e-cigarette usage might lead children to try conventional cigarettes; e-cigarettes cartridges feature flavors such as "strawberries and cream" or "blueberries and pastry" that opponents believe appeal to children.

"In no circumstances is it ever safe for youth to use e-cigarettes or be exposed to nicotine," said Laura Oliven, tobacco control manager for the Minnesota Department of Health. "It creates harms to their developing brains at a critical time."

Evidence was not strong enough for the report to suggest that e-cigarettes caused children to become habitual tobacco smokers — only that it made them more likely to one day try a cigarette.

The federal report builds a case for regulation of e-cigarettes by the U.S. Food and Drug Administration, said Mike Sheldon, a spokesman for ClearWay Minnesota, the smoking cessation program funded by Minnesota's settlement against the tobacco industry.

The products contain different and unreported levels of nicotine and other ingredients that are poorly studied, he said.

"We can say that e-cigarettes are safer, or less harmful, than regular cigarettes, but that's still a pretty low bar to clear," Sheldon said. "And safer isn't safe."

The report was commissioned in 2016, after the FDA gained the authority to regulate tobacco products that had been outside its jurisdiction, such as e-cigarettes and cigars.

The report noted that e-cigarettes have some potential to help people quit smoking, but do not offer health benefits if people alternate between e-cigarettes and tobacco.

Kingston and Schutte both turned to e-cigarettes to quit smoking in 2014 after a state cigarette tax increase made their old habits unaffordable.

Kingston, an IT engineer, went from cigarettes to e-cigarettes to hard candy. Now he doesn't consume any of them.

"My kids … were very proud of me for that," he said.

Schutte still uses e-cigarettes and said he feels better. People at his church wonder why his singing voice is so much better now.

"Are you taking vocal lessons or something?" they ask.

Sheldon said using e-cigarettes to quit remains problematic because of the lack of oversight over their ingredients. He encouraged Minnesotans to quit smoking instead by taking advantage of ClearWay's counseling and support. "There's still no magic bullet," he said, "that helps everybody quit."

Jeremy Olson • 612-673-7744 This report contains information from the New York Times.