SEATTLE - A shocking number of children have become sick after ingesting liquid nicotine found in e-cigarettes, says the Washington Poison Center.



The total number of calls to the center about e-cigarettes is up 600 percent compared with recent years. There's also a staggering increase in the number of kids exposed to serious levels of nicotine.



The phenomenon of using an e-cigarette, called vaping, is gaining in popularity.



Oftentimes the products look like candy, attracting curious little ones - but the Poison Center says a single mouthful can harm a child.



"Sick from nicotine includes things like vomiting, ultimately, if they've taken enough of it - which isn't very much if you're dealing with taking concentrated nicotine," says Dr. Lewis Nelson, a medical toxicologist. "Muscle paralysis and even death is possible)



And he says it's easy to ingest too much of it, since it's so concentrated.



A typical e-cigarette chamber can hold up to 3 milliliters of liquid nicotine. Nicotine concentration in commonly available products can range from 6 milligrams per milliliter all the way up to 24 milligrams per milliliter. That means one e-cigarette can contain anywhere from 18 to 72 milligrams of nicotine.



In comparison, one cigarette can contain 8 to 20 milligrams of nicotine.



So far this year 83 children have been over-exposed to liquid nicotine, compared with 50 exposures in 2013. And when the center breaks it down by age, we learn that 82 percent of the e-cigarette exposures this year occurred in children ages to 1 to 3.



And it's not just young ones who end up over-exposed to liquid nicotine. Month to month, the number of calls to the poison center have doubled, sometimes even tripled since 2012.