Massachusetts Attorney General Maura Healey said vaping is the “number one issue” she hears about from parents.

During an interview on Boston Public Radio, Healey said e-cigarette companies are “ripping a page from Big Tobacco” in their predatory marketing campaigns aimed at children.

Healey said that by using cartoon characters, adding flavors and advertising on social media JUUL and other companies are targeting a young audience.

“[Vaping] has taken hold in high schools and middle schools around the state,” Healey said. She shared an anecdote from a school nurse who told Healey 80 percent of the children at her school are vaping. Smoke alarms are constantly going off in school bathrooms, Healey said.

READ MORE: ‘It infects social groups:’ Vaping and e-cigarette use in schools skyrockets; why you should care

The Centers for Disease Control reported in a study that the share of teens vaping increased from 11.7 percent in 2017 to 20.8 percent in 2018.

Healey said during a recent visit to a Massachusetts middle school, she asked a classroom full of kids to raise their hand if they knew a peer who was vaping. Every child raised a hand.

“Both kids and their parents think this stuff is harmless water flavored juice,” she said. “It’s not. It contains nicotine.”

One JUUL cartridge contains the same amount of nicotine as 20 cigarettes, according to the company’s website.

Healey has taken on the vaping industry. Her office is investigating JUUL. She has also filed a suit against Eon Smoke, a New Jersey-based e-cigarette company that used social media marketing to market its products to young consumers.

Last week, Healey called on state lawmakers to move forward with legislation that bans flavored tobacco products, including vapes, from retailers across the commonwealth.

“The research is clear: flavor in tobacco products increases their appeal to young people and promotes initiation,” Healey said during the Joint Committee on Public Health hearing Tuesday afternoon. “The good news is we know what works. We’ve fought Big Tobacco before and won.”

READ MORE: Attorney General Maura Healey says unregulated e-cigarette flavors getting a new generation hooked on nicotine

When she speaks with Massachusetts parents, Healey said vaping is a major concern. More and more pediatricians are treating kids for nicotine addiction, she said.

“For developing lungs and brain function any pediatrician will tell you nicotine is highly problematic,” Healey said.