The growing popularity of e-cigarettes has put more kids at risk of nicotine poisoning, leading to hospitalizations, coma and in one case, death, according to a national study.

The study, published in Pediatrics, analyzed calls to poison centers and found that the number of e-cigarette calls increased 15-fold by the end of the 40-month study. The monthly number of calls involving e-cigarettes increased from 14 to 223, between 2012 and 2015.

“That by any definition is an epidemic,” said Dr. Gary Smith, the lead author of the study and Director of the Center for Injury Research and Policy at Nationwide Children’s Hospital in Columbus, Ohio.

In Central Florida, the number of calls for e-cigarette exposure increased from three in 2011 to 11 in 2015, said Adam Wood, clinical toxicologist at Nemours Children’s Hospital. Statewide, that number rose from eight to 105 during that period.

It’s been known for decades that nicotine is a toxic substance, particularly for kids, but the rapid growth of the e-cigarette industry has made it more accessible to small children at home.

There are now more than 400 brands and 7,700 flavors of liquid nicotine, since e-cigarettes entered the U.S. market in 2007. Many of the e-cigarettes and refill containers are not child proof.

And while cigarettes are more difficult to digest, liquid nicotine is easily absorbed and in high concentrations can quickly poison small children.

Smith’s study showed that kids under 6 who were exposed to e-cigarettes and liquid nicotine were five times as likely to end up in the hospital compared with kids who were exposed to cigarettes. They were also nearly three times as likely to have severe outcomes.

The study comes at the heels two new initiatives to curb this trend.

The Child Nicotine Poisoning Prevention Act will take effect this summer and will require child-resistant packaging on liquid nicotine containers.

Also, the Food and Drug Administration released long-awaited rules last week, requiring e-cigarette companies to undergo federal review to stay on the market and add health warnings to their products. The new regulations, which take effect in August, also ban the sale of e-cigarettes to anyone under the age of 18.

The announcement was welcomed by many health and consumer advocacy groups, but was criticized by the vapor industry.

“Today’s action by the FDA will do nothing to improve our nation’s public health objectives,” said Tony Abboud, Vapor Technology Association’s national legislative director, in a statement. “To the contrary, today’s action will yank responsibly manufactured vapor products from the hands of adult smokers and replace them with the tobacco cigarettes they had been trying to give up.”

This trend bears a resemblance to the spike in kids’ poisoning from laundry detergent packs. A 7-month-old Osceola boy died in 2013 after eating one of the packs and Smith’s group has published several studies on the trend.

“[Liquid nicotine] is another example of a highly toxic product that was put into the marketplace without consideration for safety of children,” Smith said. “It’s as if we’re treating our children as canaries in the coal mine. We wait until there’s a dramatic event and then do something.”

If your child swallows liquid nicotine, don’t induce vomiting, advised Wood of Nemours. Instead, either call poison control, 800-222-1222 FREE or 9-1-1.

“Keep [e-cigarettes] away from kids and when you’re done using them, put them away,” said Smith.