IntroductionA recent study raised concerns about e-cigarette liquids
toxicity by reporting the presence of 14 flavouring chemicals with
toxicity classification. However, the relevant toxicity classification
was not estimated according to the measured concentrations. The purpose
of this study was to calculate the toxicity classification for different
health hazards for all the flavouring chemicals at the maximum
concentrations reported.MethodsThe analysis was based on the European
Union Classification Labelling and Packaging regulation. The
concentration of each flavouring chemical was compared with the minimum
concentration needed to classify it as toxic. Additionally, toxicity
classification was examined for a theoretical e-cigarette liquid
containing all flavouring chemicals at the maximum concentrations
reported.ResultsThere was at least one toxicity classification for all
the flavouring chemicals, with the most prevalent classifications
related to skin, oral, eye and respiratory toxicities. One chemical
(methyl cyclopentenolone) was found at a maximum concentration 150.7%
higher than that needed to be classified as toxic. For the rest, the
maximum reported concentrations were 71.6 to >99.9% lower than toxicity
concentrations. A liquid containing all flavouring compounds at the
maximum concentrations would be classified as toxic for one category
only due to the presence of methyl cyclopentenolone; a liquid without
methyl cyclopentenolone would have 66.7 to >99.9% lower concentrations
of flavourings than those needed to be classified as
toxic.ConclusionsThe vast majority of flavouring compounds in
e-cigarette liquids as reported in a recent study were present at levels
far lower than needed to classify them as toxic. Since exceptions exist,
regulatory monitoring of liquid composition is warranted