SALT LAKE CITY (AP) — Poison control workers say that as the e-cigarette industry has boomed, the number of children exposed to the liquid nicotine that gives hand-held vaporizing gadgets their kick also is spiking.

The American Association of Poison Control Centers reports that more than 2,700 people have called about a liquid nicotine exposure this year, up from a few hundred cases three years ago.

Though new products often bring a spike in calls to poison control, authorities say liquid nicotine is dangerous because it’s more concentrated than traditional cigarettes and comes in candy flavors that can attract kids.

Officials are calling for child-resistant caps on refill bottles, which industry representatives say many manufacturers have already begun using.

There’s no uniform standard, however, because the e-cigarette industry doesn’t face the strict regulations governing traditional smokes.