E-cigarette makers are quickly producing new flavors to attract customers, The New York Times reports. More than 7,000 flavors are now available, with an estimated 250 new varieties being introduced each month.

As fewer Americans smoke, tobacco companies are increasingly turning their attention to e-cigarettes. This week, Reynolds American agreed to buy Lorillard, joining two of the country’s largest tobacco manufacturers. Both companies are ramping up their production of e-cigarettes.

E-cigarette makers say offering a variety of flavors differentiates them from regular cigarettes.

In April, the Food and Drug Administration (FDA) announced new rules that would allow the agency to regulate e-cigarettes. The proposed rules would ban the sale of e-cigarettes, cigars and pipe tobacco to anyone under age 18. The proposed rules do not ban flavors in e-cigarettes and cigars. Public health advocates say these flavors entice children to try the products. The rules also do not ban marketing of e-cigarettes, which public health advocates had called for. The FDA said further regulations will be needed to address flavoring and marketing.

The e-cigarette company NJOY has announced it will add flavors including “Butter Crumble” and “Black and Blue Berry.” NJOY’s chief executive, Craig Weiss, told the newspaper, “Flavor is essential to vapers’ satisfaction.” He said research funded by his company showed that flavors “provide no additional appeal to youth.”

”It defies logic to think that such flavors would not make e-cigarette use more appealing and even normal for children,” said James Pankow, a chemistry professor at Portland State University, who has studied cancer and cigarettes.

Earlier this year, U.S. Senator Dick Durbin of Illinois released a report about e-cigarettes that found six of the nine surveyed e-cigarette companies market e-cigarettes in flavors, like Cherry Crush, Chocolate Treat, Peachy Keen and Grape Mint, that could appeal to children and teens.