Last year, one in five U.S. high school students reported vaping the previous month, according to a survey conducted by the CDC. Vaping is on the rise—and so are vaping-related hospitalizations. Why are so many teens vaping? What are the health effects? And why have cities around the country been issuing warnings to stop vaping immediately?

To give us a lay of the land, we first speak to Michael Stevenson, interim director of policy and planning at the City of Milwaukee Health Department, and Nina Gregerson, health education coordinator for Public Health Madison & Dane County. They talk about the dangers of vaping and e-cigarettes, especially for youth, and the public health initiatives being undertaken in Madison, Milwaukee, and throughout Wisconsin.

Then, Jeffrey Drope, scientific vice president of economic and health policy research at the American Cancer Society, offers some political and economic context, including the vaping industry’s lobbying and marketing strategies—and why we should all be watching this issue closely.