title: Variations in label information and nicotine levels in electronic cigarette refill liquids in South Korea: regulation challenges.
abstract: BACKGROUND
  In South Korea, the consumption of liquid nicotine used in electronic cigarettes has dramatically increased from 4310 L in 2012 to 7220 L in 2013. This study aimed to examine the level of heterogeneity of contents of the labels and discrepancy of the nicotine content between that indicated on the label and the actual values for electronic cigarette liquid refill products in South Korea.
  
  
  METHODS
  We purchased 32 electronic cigarette liquid refill products (17 Korean domestic, 15 imported ones) and one pure nicotine product at six different electronic cigarette retail stores in Seoul between May and June 2014. The actual nicotine concentrations of each product were measured by a blinded analyst at Roswell Park Cancer Institute, Buffalo, NY, USA.
  
  
  RESULTS
  Three out of 15 imported liquid refill products provided manufacturing dates, while expiration dates were available on eight products. The range of nicotine concentration was from "not detected" to 17.5 mg/mL. Labeling discrepancies of the concentrations ranged from -32.2% to 3.3% among electronic cigarette liquid refill products. The highest concentration (150.3 ± 7.9 mg/mL) was found in a sample labeled as "pure nicotine".
  
  
  CONCLUSIONS
  There is no standardization of labelling among electronic cigarette liquids sampled from retail stores and the labels did not accurately reflect the content. One product labeled "pure nicotine" raises concerns, since it may be poisonous to consumers, especially to children. This study revealed the urgent need for the development of product regulations in South Korea.
authors.affiliation: Department of Environmental Health Sciences, Soonchunhyang University, Asan-city 336-745, South Korea. Sungroul.kim@gmail.com.
authors.forename: Sungroul
authors.initials: S
authors.lastname: Kim
authors.affiliation: Division of Cancer Prevention and Population Sciences, Department of Health Behaviors, Roswell Park Cancer Institute, Buffalo, NY 14263, USA. maciej.goniewicz@roswellpark.org.
authors.forename: Maciej L
authors.initials: ML
authors.lastname: Goniewicz
authors.affiliation: Department of Environmental Health Sciences, Soonchunhyang University, Asan-city 336-745, South Korea. solsol0914@gmail.com.
authors.forename: Sol
authors.initials: S
authors.lastname: Yu
authors.affiliation: Department of Environmental Health Sciences, Soonchunhyang University, Asan-city 336-745, South Korea. qhrud0309@gmail.com.
authors.forename: Bokyeong
authors.initials: B
authors.lastname: Kim
authors.affiliation: Division of Cancer Prevention and Population Sciences, Department of Health Behaviors, Roswell Park Cancer Institute, Buffalo, NY 14263, USA. ribhav.gupta97@gmail.com.
authors.forename: Ribhav
authors.initials: R
authors.lastname: Gupta
mesh_terms: D066300:Electronic Nicotine Delivery Systems; D033161:Government Regulation; D009538:Nicotine / Q000032:analysis*; D011356:Product Labeling / Q000331:legislation & jurisprudence*; D056910:Republic of Korea
chemical_list: D009538:Nicotine