Millions of Americans now are using e-cigarettes—battery-operated nicotine-delivery systems that mimic conventional cigarettes, except that nicotine vapor is inhaled into the lungs, not smoke. The jury remains out on whether these e-cigarettes truly offer lower cancer risks than conventional cigarettes. What we do know is that e-cigarettes pose an entirely new danger—poisoning.

The concentrated liquid nicotine used in e-cigarettes is highly toxic, yet the owners of refillable e-cigarette systems typically keep bottles of it in their homes. Ingesting even a small amount of this liquid—or accidentally spilling it onto your skin—can cause nausea and vomiting. In some victims, it increases blood pressure and heart rate, too. Larger doses can be fatal. Many e-cigarette users are completely in the dark about these risks. Liquid nicotine is not currently regulated by the federal government, so many products do not carry warnings.

We’ve been lucky so far—there have been no recent deaths caused by accidental liquid nicotine poisoning in the US (though it was injected in one apparent suicide). But the number of accidental nicotine poisonings has been increasing as e-cigarettes gain popularity. It was responsible for 1,351 reported poisonings in 2013, up 300% from 2012. It’s not a matter of if someone will die from liquid nicotine poisoning but when. If you purchase liquid nicotine…

Keep it out of the reach of young children, just as you would a dangerous household cleaner. Choose products that have child-resistant caps.

Wear rubber gloves when handling liquid nicotine. It is very readily absorbed into the skin.

Do not store liquid nicotine where you keep your eyedrops. Liquid nicotine often is sold in small bottles that feature eyedroppers built into their caps—just like eyedrops. We have seen several cases of people accidentally grabbing these bottles when they’re reaching for their eyedrops and ending up with liquid nicotine in their eyes. The result is both nicotine poisoning and extreme eye irritation.