As the use of e-cigarettes has risen dramatically in the United States in recent years, so have calls to poison centers about them, yet most parents are unaware of potential dangers.

The devices are used like cigarettes but instead of tobacco, they vaporize a liquid mixture of nicotine, glycerin and glycol ethers. If ingested, a teaspoon of this "e-liquid" can be lethal to a child, and smaller amounts can cause nausea and vomiting that may necessitate a trip to the  emergency room. In a few cases, exposure to skin has also sickened children.

A new study at Washington University School of Medicine in St. Louis says parents and caregivers don't consider the risks of e-cigarettes because they are not harmful like cigarettes or alcohol or guns - but knives are dangerous for kids, even if they are not guns.

658 parents and guardians at 15 pediatric clinics in the St. Louis area completed surveys about their knowledge and use of e-cigarettes. Almost all parents knew about e-cigarettes: 1 in 5 had tried them, and 1 in 8 said a family member regularly smoked e-cigarettes. In two-thirds of the homes where children were exposed to e-cigarettes, they also were exposed to regular cigarettes.

The researchers found that 36 percent of the e-cigarette users neither locked up e-liquid bottles nor used childproof caps. Such caps, required in Europe, are not mandated in the United States. E-liquid most commonly was stored in a drawer or cupboard (34 percent), a purse or bag (22 percent) or on an open counter (13 percent), the study showed.

"These are largely avoidable risks, but because e-cigarettes are relatively new, many people - including pediatricians - aren't aware of the dangers or the steps that should be taken to protect children from them," said first author Jane Garbutt, MD, a professor of medicine and of pediatrics at the School of Medicine.  

Only three parent of surveyed people said a child had tried to drink the liquid but the risk could easily approach zero with proper storage. In once case, a toddler in New York died after ingesting liquid nicotine intended for use in an e-cigarette.

Among survey participants, 15 percent of e-cigarette users reported that they had told their pediatricians they were using the devices and six percent said doctors had discussed with them the use and safe storage of e-cigarettes.

Citation: Garbutt JM, Miller W, Dodd S, Bobenhouse N, Sterkel R, Strunk RC. Parental use of electronic cigarettes. Academic Pediatrics, Aug. 25, 2015. Funding from the Washington University Institute of Clinical and Translational Sciences, grant UL1 TR000448 from the National Center for Advancing Translational Sciences (NCATS) of the National Institutes of Health (NIH), with co-funding from St. Louis Children's Hospital.