To Chris Chin, owner of the Gone With the Smoke vapor shop in San Francisco, the city’s proposed legislation to ban the sale of e-cigarettes would mark an end to his nearly six-year run in the Tenderloin neighborhood.

“They’re going to absolutely put me out of business, 100%,” said Chin, who in recent weeks has delayed restocking many of his products in case the legislation passes.

“I’d have to change product, go to something totally different, like clothing, perfume, makeup, I have no idea,” Chin said. “That’s what I’m going to have to figure out, what I’m going to do next. If I don’t, I’m screwed because I’m on the hook for another year and a half on my lease. I’d have to scramble to find a sublease.”

Chin is one of about 730 San Francisco tobacco retailers whose business would take a hit or be snuffed out entirely by the proposed ban on e-cigarettes, which City Attorney Dennis Herrera and Supervisor Shamann Walton are spearheading as an attempt to curb youth vaping. The ban, which includes online sales to San Francisco addresses, would last until the U.S. Food and Drug Administration conducts a review to ensure the safety of e-cigarettes.

Walton said he has encouraged vape-only stores to consider selling other products.

It is unclear how much in annual tax revenue would be lost if a vape ban were to be implemented in San Francisco. The city does not collect taxes from the sale of tobacco products, according to the Office of the Treasurer and Tax Collector. Tobacco retailers pay sales tax to the state but the California Department of Tax and Fee Administration does not break out sales tax revenue by product type.

Ted Egan, the city’s chief economist, said his office reviewed the legislation and found it would not have a material impact on the San Francisco economy because the money spent on vaping products would continue to be spent in the city on other nicotine products like cigarettes.

“E-cigarettes haven’t been around forever,” Walton said. “A lot of these stores were thriving before e-cigarettes. If we work together, they’ll continue to thrive. But it’s more important to keep our young people safe.”

Youth vaping has grown significantly over the past few years, worrying public health experts because teens whose brains are still developing are being exposed to nicotine, a highly addictive substance. About 3.6 million high school and middle school students vape regularly — a major spike from 280,000 in 2011, according to the National Youth Tobacco Survey.

The long-term health effects of e-cigarettes are unknown because they have not been studied long enough, or in large enough groups of people, to draw definitive conclusions. Researchers believe vaping benefits adult cigarette smokers trying to quit, who report less coughing and wheezing after switching to vaping, while potentially harming others, like kids who wouldn’t have started smoking if not for the fruit- and candy-flavored vapor.

“We’re not prepared to sacrifice another generation of children to nicotine addiction for a product that, by law, should not be on the market,” said John Coté, a spokesman for Herrera. “If companies want to sell e-cigarettes in San Francisco, they should apply to the FDA for review. ... If the FDA hasn’t reviewed it and determined it to be safe for public health, it shouldn’t be sold in San Francisco.”

Less than 14% of San Francisco high school students who vape got their e-cigarette products in a store; the remaining 86% got it from friends and classmates or on the internet, according to a survey by the U.S. Centers for Disease Control and Prevention.

Walton said the aim is not to target small businesses, but rather to cut off the entire e-cigarette supply in the city, including those from big-box retailers and Internet sales.

Because many of the city’s tobacco retailers are minority- or immigrant-owned, the proposed ban would disproportionately hurt local merchants of color, said Miriam Zouzounis of the Arab American Grocers Association, which represents about 400 businesses in the Bay Area. Zouzounis is also a member of the San Francisco Small Business Commission, which recently recommended the Board of Supervisors vote against the measure unless it includes an amendment that would exempt brick-and-mortar retailers.

Most licensed tobacco retailers in San Francisco are owned by Arab, African, South Asian or Asian store owners, according to data provided by the grocers association to the small business commission. Even those that sell a variety of goods besides vaping products, like corner markets, estimate they would lose tens of thousands of dollars each month if they could no longer sell e-cigarettes.

Many stores including Chin’s had already been seeing a slowdown in business since the city banned the sale of flavored tobacco products like the fruit- and candy-flavored nicotine pods made by Juul. The flavored tobacco ban, which was passed in 2018 and took effect in January, was similarly enacted to try to deter teens from vaping. A spokeswoman for the San Francisco Department of Public Health said the department will be tracking whether the flavor ban affects youth tobacco use, she said.

San Francisco’s flavor ban has already appeared to pull some business away from the city’s retailers and shifted it to surrounding cities like Oakland and Daly City. Chin’s store has seen annual revenue drop 20% from about $500,000 to $400,000, since the flavor ban. At the same time, customer demand at vape shops in Daly City is picking up, said Amjad Hannoneh, CEO of the Royale Group, a Pleasanton company that manufactures and distributes e-cigarettes globally, including to about 70 stores in the Bay Area.

In the months before San Francisco’s flavor ban went into effect, Hannoneh saw a major drop-off in purchase orders of vape products from San Francisco stores, while Daly City stores increased their orders 20% to 30%.

Hannoneh opposes San Francisco’s proposed vape ban, saying adults who buy the products legally should have the freedom to do so — just like with other addictive substances, such as alcohol or coffee.

Chin said many of his customers are adult former cigarette smokers who say switching to e-cigarettes has helped them breathe more easily. Most, he said, are in their late 20s or early 30s. Occasionally, he will turn away an under-21 customer from out of town who doesn’t realize the legal age to buy tobacco in California is 21, not 18, as it is in many states.

Some San Franciscans who vape, like Matt Gram — one of Chin’s regular customers — feel city officials are imposing a double standard by cracking down on e-cigarettes but not regular cigarettes or alcohol. Gram, 38, said if San Francisco bans the sale of e-cigarettes, he would BART to Daly City and buy in bulk there.

“I think it’s ridiculous,” he said. “Let adults choose for themselves. Let people who are 21 buy the products. If you’re going to ban (e-cigarette) flavors, then ban flavored alcohol in bars. ... I’d say to the city: How dare you try to tell me what I can and can’t buy online?”

Catherine Ho is a San Francisco Chronicle staff writer. Email: cho@sfchronicle.com Twitter: @Cat_Ho