Study on Potential Toxicity of E-Cigarette Flavorings Produces Unwarranted Scare

A study published in the journal Tobacco Control this past April has produced an unwarranted scare about the potential toxicity of the flavorings in electronic cigarettes.

(See: Tierney PA, et al. Flavour chemicals in electronic cigarette fluids. Tobacco Control. Published online ahead of print on April 15, 2015. DOI: 0.1136/tobaccocontrol-2014-052175.)

The study used gas chromatography/mass spectrometry to analyze the chemical constituents in e-liquids of various flavors. It appears that 30 different e-liquid flavors were tested. Multiple flavors of two brands of disposable e-cigarettes (Blu and NJOY) were tested along with a convenience sample of e-liquids obtained from vape shops.

The results were reported as follows: "In many liquids, total flavour chemicals were found to be in the∼1–4% range (10–40 mg/mL); labelled levels of nicotine were in the range of 0.6–2.4% (6 to 24 mg/mL). A significant number of the flavour chemicals were aldehydes, a compound class recognised as 'primary irritants’ of mucosal tissue of the respiratory tract. Many of the products contained the same flavour chemicals: vanillin and/or ethyl vanillin was found in 17 of the liquids as one of the top three flavour chemicals, and/or at ≥ 0.5 mg/mL."

The study concludes as follows: "The concentrations of some flavour chemicals in e-cigarette fluids are sufficiently high for inhalation exposure by vaping to be of toxicological concern. Regulatory limits should be contemplated for levels of some of the more worrisome chemicals as well as for total flavour chemical levels. Ingredient labeling should also be required."

The reporting of the results of this study in the media has resulted in a health scare about the potential dangers of electronic cigarettes, with some policy makers calling for a complete ban on e-cigarette flavorings.

The Rest of the Story

Here are the chemicals that were found in the e-cigarettes:

Benzalkonium chloride: may cause rapid onset bronchoconstriction

Oleic acid: may cause respiratory irritation

Chlorofluorocarbons: destroys the ozone layer

Soya lecithin: may cause respiratory irritation

Sorbitan trioleate: may cause respiratory irritation

Sulfites: may cause life-threatening respiratory reactions

Methylparaben: possible link to breast cancer at high concentrations

Propylparaben: possible link to breast cancer at high concentrations

SORRY - that was a mistake. The above is NOT a list of the inactive chemical ingredients in e-liquids. It is a list of the inactive ingredients that have been detected in pharmaceutical inhalers, approved by the FDA.

Let's try again. Here are the chemicals that were found in the e-cigarettes:

Acetanisole, · Acetic Acid, · Acetoin, · Acetophenone, · 6-Acetoxydihydrotheaspirane, · 2-Acetyl-3- Ethylpyrazine, · 2-Acetyl-5-Methylfuran, · Acetylpyrazine, · 2-Acetylpyridine, · 3-Acetylpyridine, · 2-Acetylthiazole, · Aconitic Acid, · dl-Alanine, · Alfalfa Extract, · Allspice Extract, · Oleoresin, · And Oil, · Allyl Hexanoate, · Allyl Ionone, · Almond Bitter Oil, · Ambergris Tincture, · Ammonia, · Ammonium Bicarbonate, · Ammonium Hydroxide, · Ammonium Phosphate Dibasic, · Ammonium Sulfide, · Amyl Alcohol, · Amyl Butyrate, · Amyl Formate, · Amyl Octanoate, · alpha-Amylcinnamaldehyde, · Amyris Oil, · trans-Anethole, · Angelica Root Extract, Oil and Seed Oil, · Anise, · Anise Star, Extract and Oils, · Anisyl Acetate, · Anisyl Alcohol, · Anisyl Formate, · Anisyl Phenylacetate, · Apple Juice Concentrate, Extract, and Skins, · Apricot Extract and Juice Concentrate, · 1-Arginine, · Asafetida Fluid Extract And Oil, · Ascorbic Acid, · 1-Asparagine Monohydrate, · 1-Aspartic Acid, · Balsam Peru and Oil, · Basil Oil, · Bay Leaf, Oil and Sweet Oil, · Beeswax White, · Beet Juice Concentrate, · Benzaldehyde, · Benzaldehyde Glyceryl Acetal, · Benzoic Acid, Benzoin, · Benzoin Resin, · Benzophenone, · Benzyl Alcohol, · Benzyl Benzoate, · Benzyl Butyrate, · Benzyl Cinnamate, · Benzyl Propionate, · Benzyl Salicylate, · Bergamot Oil, · Bisabolene, · Black Currant Buds Absolute, · Borneol, · Bornyl Acetate, · Buchu Leaf Oil, · 1,3-Butanediol, · 2,3-Butanedione, · 1-Butanol, · 2-Butanone, · 4(2-Butenylidene)-3,5,5-Trimethyl-2-Cyclohexen-1-One, · Butter, Butter Esters, and Butter Oil, · Butyl Acetate, · Butyl Butyrate, · Butyl Butyryl Lactate, · Butyl Isovalerate, · Butyl Phenylacetate, · Butyl Undecylenate, · 3-Butylidenephthalide, · Butyric Acid, · Cadinene, · Caffeine, · Calcium Carbonate, · Camphene, · Cananga Oil, · Capsicum Oleoresin, · Caramel Color, · Caraway Oil, · Carbon Dioxide, · Cardamom Oleoresin, Extract, Seed Oil, and Powder, · Carob Bean and Extract, · beta-Carotene, · Carrot Oil, · Carvacrol, · 4-Carvomenthenol, · 1-Carvone, · beta-Caryophyllene, · beta-Caryophyllene Oxide, · Cascarilla Oil and Bark Extract, · Cassia Bark Oil, · Cassie Absolute and Oil, · Castoreum Extract, Tincture and Absolute, · Cedar Leaf Oil, · Cedarwood Oil Terpenes and Virginiana, · Cedrol, · Celery Seed Extract, Solid, Oil, And Oleoresin, · Cellulose Fiber, · Chamomile Flower Oil And Extract, · Chicory Extract, · Chocolate, · Cinnamaldehyde, · Cinnamic Acid, · Cinnamon Leaf Oil, Bark Oil, and Extract, · Cinnamyl Acetate, · Cinnamyl Alcohol, · Cinnamyl Cinnamate, · Cinnamyl Isovalerate, · Cinnamyl Propionate, · Citral, · Citric Acid, · Citronella Oil, · dl-Citronellol, · Citronellyl Butyrate, · Citronellyl Isobutyrate, · Civet Absolute, · Clary Oil, · Clover Tops, Red Solid Extract, · Cocoa, · Cocoa Shells, Extract, Distillate And Powder, · Coconut Oil, · Coffee, · Cognac White and Green Oil, · Copaiba Oil, · Coriander Extract and Oil, · Corn Oil, · Corn Silk, · Costus Root Oil, · Cubeb Oil, · Cuminaldehyde, · para-Cymene, · 1-Cysteine, · Dandelion Root Solid Extract, · Davana Oil, · 2-trans, 4-trans-Decadienal, · delta-Decalactone, · gamma-Decalactone, · Decanal, · Decanoic Acid, · 1-Decanol, · 2-Decenal, · Dehydromenthofurolactone, · Diethyl Malonate, · Diethyl Sebacate, · 2,3-Diethylpyrazine, · Dihydro Anethole, · 5,7-Dihydro-2-Methylthieno(3,4-D) Pyrimidine, · Dill Seed Oil and Extract, · meta-Dimethoxybenzene, · para-Dimethoxybenzene, · 2,6-Dimethoxyphenol, · Dimethyl Succinate, · 3,4-Dimethyl-1,2-Cyclopentanedione, · 3,5- Dimethyl-1,2-Cyclopentanedione, · 3,7-Dimethyl-1,3,6-Octatriene, · 4,5-Dimethyl-3-Hydroxy-2,5-Dihydrofuran-2-One, · 6,10-Dimethyl-5,9-Undecadien-2-One, · 3,7-Dimethyl-6-Octenoic Acid, · 2,4-Dimethylacetophenone, · alpha,para-Dimethylbenzyl Alcohol, · alpha,alpha-Dimethylphenethyl Acetate, · alpha,alpha Dimethylphenethyl Butyrate, · 2,3-Dimethylpyrazine, · 2,5-Dimethylpyrazine, · 2,6-Dimethylpyrazine, · Dimethyltetrahydrobenzofuranone, · delta-Dodecalactone, · gamma-Dodecalactone, · para-Ethoxybenzaldehyde, · Ethyl 10-Undecenoate, · Ethyl 2-Methylbutyrate, · Ethyl Acetate, · Ethyl Acetoacetate, · Ethyl Alcohol, · Ethyl Benzoate, · Ethyl Butyrate, · Ethyl Cinnamate, · Ethyl Decanoate, · Ethyl Fenchol, · Ethyl Furoate, · Ethyl Heptanoate, · Ethyl Hexanoate, · Ethyl Isovalerate, · Ethyl Lactate, · Ethyl Laurate, · Ethyl Levulinate, · Ethyl Maltol, · Ethyl Methyl Phenylglycidate, · Ethyl Myristate, · Ethyl Nonanoate, · Ethyl Octadecanoate, · Ethyl Octanoate, · Ethyl Oleate, · Ethyl Palmitate, · Ethyl Phenylacetate, · Ethyl Propionate, · Ethyl Salicylate, · Ethyl trans-2-Butenoate, · Ethyl Valerate, · Ethyl Vanillin, · 2-Ethyl (or Methyl)-(3,5 and 6)-Methoxypyrazine, · 2-Ethyl-1-Hexanol, 3-Ethyl -2 -Hydroxy-2-Cyclopenten-1-One, · 2-Ethyl-3, (5 or 6)-Dimethylpyrazine, · 5-Ethyl-3-Hydroxy-4-Methyl-2(5H)-Furanone, · 2-Ethyl-3-Methylpyrazine, · 4-Ethylbenzaldehyde, · 4-Ethylguaiacol, · para-Ethylphenol, · 3-Ethylpyridine, · Eucalyptol, · Farnesol, · D-Fenchone, · Fennel Sweet Oil, · Fenugreek, Extract, Resin, and Absolute, · Fig Juice Concentrate, · Food Starch Modified, · Furfuryl Mercaptan, · 4-(2-Furyl)-3-Buten-2-One, · Galbanum Oil, · Genet Absolute, · Gentian Root Extract, · Geraniol, · Geranium Rose Oil, · Geranyl Acetate, · Geranyl Butyrate, · Geranyl Formate, · Geranyl Isovalerate, · Geranyl Phenylacetate, · Ginger Oil and Oleoresin, · 1-Glutamic Acid, · 1-Glutamine, · Glycerol, · Glycyrrhizin Ammoniated, · Grape Juice Concentrate, · Guaiac Wood Oil, · Guaiacol, · Guar Gum, · 2,4-Heptadienal, · gamma-Heptalactone, · Heptanoic Acid, · 2-Heptanone, · 3-Hepten-2-One, · 2-Hepten-4-One, · 4-Heptenal, · trans -2-Heptenal, · Heptyl Acetate, · omega-6-Hexadecenlactone, · gamma-Hexalactone, · Hexanal, · Hexanoic Acid, · 2-Hexen-1-Ol, · 3-Hexen-1-Ol, · cis-3-Hexen-1-Yl Acetate, · 2-Hexenal, · 3-Hexenoic Acid, · trans-2-Hexenoic Acid, · cis-3-Hexenyl Formate, · Hexyl 2-Methylbutyrate, · Hexyl Acetate, · Hexyl Alcohol, · Hexyl Phenylacetate, · 1-Histidine, · Honey, · Hops Oil, · Hydrolyzed Milk Solids, · Hydrolyzed Plant Proteins, · 5-Hydroxy-2,4-Decadienoic Acid delta- Lactone, · 4-Hydroxy-2,5-Dimethyl-3(2H)-Furanone, · 2-Hydroxy-3,5,5-Trimethyl-2-Cyclohexen-1-One, · 4-Hydroxy -3-Pentenoic Acid Lactone, · 2-Hydroxy-4-Methylbenzaldehyde, · 4-Hydroxybutanoic Acid Lactone, · Hydroxycitronellal, · 6-Hydroxydihydrotheaspirane, · 4-(para-Hydroxyphenyl)-2-Butanone, · Hyssop Oil, · Immortelle Absolute and Extract, · alpha-Ionone, · beta-Ionone, · alpha-Irone, · Isoamyl Acetate, · Isoamyl Benzoate, · Isoamyl Butyrate, · Isoamyl Cinnamate, · Isoamyl Formate, Isoamyl Hexanoate, · Isoamyl Isovalerate, · Isoamyl Octanoate, · Isoamyl Phenylacetate, · Isobornyl Acetate, · Isobutyl Acetate, · Isobutyl Alcohol, · Isobutyl Cinnamate, · Isobutyl Phenylacetate, · Isobutyl Salicylate, · 2-Isobutyl-3-Methoxypyrazine, · alpha-Isobutylphenethyl Alcohol, · Isobutyraldehyde, · Isobutyric Acid, · d,l-Isoleucine, · alpha-Isomethylionone, · 2-Isopropylphenol, · Isovaleric Acid, · Jasmine Absolute, Concrete and Oil, · Kola Nut Extract, · Labdanum Absolute and Oleoresin, · Lactic Acid, · Lauric Acid, · Lauric Aldehyde, · Lavandin Oil, · Lavender Oil, · Lemon Oil and Extract, · Lemongrass Oil, · 1-Leucine, · Levulinic Acid, · Licorice Root, Fluid, Extract and Powder, · Lime Oil , · Linalool, · Linalool Oxide, · Linalyl Acetate, · Linden Flowers, · Lovage Oil And Extract, · 1-Lysine, · Mace Powder, Extract and Oil , · Magnesium Carbonate, · Malic Acid, · Malt and Malt Extract, · Maltodextrin, · Maltol, · Maltyl Isobutyrate, · Mandarin Oil, · Maple Syrup and Concentrate, · Mate Leaf, Absolute and Oil, · para-Mentha-8-Thiol-3-One, · Menthol, · Menthone, · Menthyl Acetate, · dl-Methionine, · Methoprene, · 2-Methoxy-4-Methylphenol, · 2-Methoxy-4-Vinylphenol, · para-Methoxybenzaldehyde, · 1-(para-Methoxyphenyl)-1-Penten-3-One, · 4-(para-Methoxyphenyl)-2-Butanone, · 1-(para-Methoxyphenyl)-2-Propanone, · Methoxypyrazine, · Methyl 2-Furoate, · Methyl 2-Octynoate, · Methyl 2-Pyrrolyl Ketone, · Methyl Anisate, · Methyl Anthranilate, · Methyl Benzoate, · Methyl Cinnamate, · Methyl Dihydrojasmonate, · Methyl Ester of Rosin, Partially Hydrogenated, · Methyl Isovalerate, · Methyl Linoleate (48%), · Methyl Linolenate (52%) Mixture, · Methyl Naphthyl Ketone, · Methyl Nicotinate, · Methyl Phenylacetate, · Methyl Salicylate, · Methyl Sulfide, · 3-Methyl-1-Cyclopentadecanone, · 4-Methyl-1-Phenyl-2-Pentanone, · 5-Methyl-2-Phenyl-2-Hexenal, · 5-Methyl-2-Thiophenecarboxaldehyde, · 6-Methyl-3,-5-Heptadien-2-One, · 2-Methyl-3-(para-Isopropylphenyl) Propionaldehyde, · 5-Methyl-3-Hexen-2-One, · 1-Methyl-3Methoxy-4-Isopropylbenzene, · 4-Methyl-3-Pentene-2-One, · 2-Methyl-4-Phenylbutyraldehyde, · 6-Methyl-5-Hepten-2-One, · 4-Methyl-5-Thiazoleethanol, · 4-Methyl-5-Vinylthiazole, · Methyl-alpha-Ionone, · Methyl-trans-2-Butenoic Acid, · 4-Methylacetophenone, · para-Methylanisole, · alpha-Methylbenzyl Acetate, · alpha-Methylbenzyl Alcohol, · 2-Methylbutyraldehyde, · 3-Methylbutyraldehyde, · 2-Methylbutyric Acid, · alpha-Methylcinnamaldehyde, · Methylcyclopentenolone, · 2-Methylheptanoic Acid, · 2-Methylhexanoic Acid, · 3-Methylpentanoic Acid, · 4-Methylpentanoic Acid, · 2-Methylpyrazine, · 5-Methylquinoxaline, · 2-Methyltetrahydrofuran-3-One * (Methylthio)Methylpyrazine (Mixture Of Isomers), · 3-Methylthiopropionaldehyde, · Methyl 3-Methylthiopropionate, · 2-Methylvaleric Acid, · Mimosa Absolute and Extract, · Molasses Extract and Tincture, · Mountain Maple Solid Extract, · Mullein Flowers, · Myristaldehyde, · Myristic Acid, · Myrrh Oil, · beta-Napthyl Ethyl Ether, · Nerol, · Neroli Bigarde Oil, · Nerolidol, · Nona-2-trans,6-cis-Dienal, · 2,6-Nonadien-1-Ol, · gamma-Nonalactone, · Nonanal, · Nonanoic Acid, · Nonanone, · trans-2-Nonen-1-Ol, · 2-Nonenal, · Nonyl Acetate, · Nutmeg Powder and Oil, · Oak Chips Extract and Oil, · Oak Moss Absolute, · 9,12-Octadecadienoic Acid (48%) And 9,12,15-Octadecatrienoic Acid (52%), · delta-Octalactone, · gamma-Octalactone, · Octanal, · Octanoic Acid, · 1-Octanol, · 2-Octanone, · 3-Octen-2-One, · 1-Octen-3-Ol, · 1-Octen-3-Yl Acetate, · 2-Octenal, · Octyl Isobutyrate, · Oleic Acid , · Olibanum Oil, · Opoponax Oil And Gum, · Orange Blossoms Water, Absolute, and Leaf Absolute, · Orange Oil and Extract, · Origanum Oil, · Orris Concrete Oil and Root Extract, · Palmarosa Oil, · Palmitic Acid, · Parsley Seed Oil, · Patchouli Oil, · omega-Pentadecalactone, · 2,3-Pentanedione, · 2-Pentanone, · 4-Pentenoic Acid, · 2-Pentylpyridine, · Pepper Oil, Black And White, · Peppermint Oil, · Peruvian (Bois De Rose) Oil, · Petitgrain Absolute, Mandarin Oil and Terpeneless Oil, · alpha-Phellandrene, · 2-Phenenthyl Acetate, · Phenenthyl Alcohol, · Phenethyl Butyrate, · Phenethyl Cinnamate, · Phenethyl Isobutyrate, · Phenethyl Isovalerate, · Phenethyl Phenylacetate, · Phenethyl Salicylate, · 1-Phenyl-1-Propanol, · 3-Phenyl-1-Propanol, · 2-Phenyl-2-Butenal, · 4-Phenyl-3-Buten-2-Ol, · 4-Phenyl-3-Buten-2-One, · Phenylacetaldehyde, · Phenylacetic Acid, · 1-Phenylalanine, · 3-Phenylpropionaldehyde, · 3-Phenylpropionic Acid, · 3-Phenylpropyl Acetate, · 3-Phenylpropyl Cinnamate, · 2-(3-Phenylpropyl)Tetrahydrofuran, · Phosphoric Acid, · Pimenta Leaf Oil, · Pine Needle Oil, Pine Oil, Scotch, · Pineapple Juice Concentrate, · alpha-Pinene, beta-Pinene, · D-Piperitone, · Piperonal, · Pipsissewa Leaf Extract, · Plum Juice, · Potassium Sorbate, · 1-Proline, · Propenylguaethol, · Propionic Acid, · Propyl Acetate, · Propyl para-Hydroxybenzoate, · Propylene Glycol, · 3-Propylidenephthalide, · Prune Juice and Concentrate, · Pyridine, · Pyroligneous Acid And Extract, * * Pyrrole, * Pyruvic Acid, * Raisin Juice Concentrate, * Rhodinol, * Rose Absolute and Oil, * Rosemary Oil, * Rum, * Rum Ether, * Rye Extract, * Sage, Sage Oil, and Sage Oleoresin, * Salicylaldehyde, * Sandalwood Oil, Yellow, * Sclareolide, * Skatole, * Smoke Flavor, * Snakeroot Oil, * Sodium Acetate, * Sodium Benzoate, * Sodium Bicarbonate, * Sodium Carbonate, * Sodium Chloride, * Sodium Citrate, * Sodium Hydroxide, * Solanone, * Spearmint Oil, * Styrax Extract, Gum and Oil, * Sucrose Octaacetate, * Sugar Alcohols, * Sugars, * Tagetes Oil, * Tannic Acid, * Tartaric Acid, * Tea Leaf and Absolute, * alpha-Terpineol, * Terpinolene, * Terpinyl Acetate, * 5,6,7,8-Tetrahydroquinoxaline, * 1,5,5,9-Tetramethyl-13-Oxatricyclo(8.3.0.0(4,9))Tridecane, * 2,3,4,5, and 3,4,5,6-Tetramethylethyl-Cyclohexanone, * 2,3,5,6-Tetramethylpyrazine, * Thiamine Hydrochloride, * Thiazole, * 1-Threonine, * Thyme Oil, White and Red, * Thymol, * Tobacco Extracts, * Tochopherols (mixed), * Tolu Balsam Gum and Extract, * Tolualdehydes, * para-Tolyl 3-Methylbutyrate, * para-Tolyl Acetaldehyde, * para-Tolyl Acetate, * para-Tolyl Isobutyrate, * para-Tolyl Phenylacetate, * Triacetin, * 2-Tridecanone, * 2-Tridecenal, * Triethyl Citrate, * 3,5,5-Trimethyl -1-Hexanol, * para,alpha,alpha-Trimethylbenzyl Alcohol, * 4-(2,6,6-Trimethylcyclohex-1-Enyl)But-2-En-4-One, * 2,6,6-Trimethylcyclohex-2-Ene-1,4-Dione, * 2,6,6-Trimethylcyclohexa-1,3-Dienyl Methan, * 4-(2,6,6-Trimethylcyclohexa-1,3-Dienyl)But-2-En-4-One, * 2,2,6-Trimethylcyclohexanone, * 2,3,5-Trimethylpyrazine, * 1-Tyrosine, * delta-Undercalactone, * gamma-Undecalactone, * Undecanal, * 2-Undecanone, 1 * 0-Undecenal, * Urea, * Valencene, * Valeraldehyde, * Valerian Root Extract, Oil and Powder, * Valeric Acid, * gamma-Valerolactone, * Valine, * Vanilla Extract And Oleoresin, * Vanillin, * Veratraldehyde, * Vetiver Oil, * Vinegar, * Violet Leaf Absolute, * Walnut Hull Extract, * Water, * Wheat Extract And Flour, * Wild Cherry Bark Extract, * Wine and Wine Sherry, * Xanthan Gum, * 3,4-Xylenol, * Yeast Benzene 2-Napthylamine 4-Aminobiphenyl Nickel Polonium 210 (radioactive) Nitrogen oxides N-Nitrosodimethylamine N-Nitrosodiethylamine N-Nitrosopyrrolidine 1,3-Butadiene Analine Formaldehyde Hydrazine N-Nitrodiethanolamine Cadmium Benzo[a]pyrene Benz[a]anthracene Y-Butyrolactone Particulate matter N-Nitrosonornicotine NNK Carbon monoxide Carbon dioxide Carbonyl sulfide Toluene Acrolein Acetone Pyridine 3-Methylpyridine 3-Vinylpyridine Hydrogen cyanide Ammonia Methylamine Dimethylamine Nicotine Anatabine Phenol Catechol Hydorquinone Cholesterol Quinoline Harman Zinc Benzoic acid Lactic acid Glycolic acid Succinic acit PCDDs and PCDFs (Dioxins, Dibenzofurans) Formic acid Acetic acid Methyl chloride Dimethylnitrosamine Ethylmethylnitrosamine Nitrosopyrrolidine Hydrazine Vinyl Chloride Urethane Formaldehyde Carbon Monoxide Hydrogen Cyanide Acrolein Acetadehyde Nitrogen oxides Ammonia Pyridine Nitric acid Mathylamine Hydrogen cyanide Indole 3-hydroxypyridine 3-vinylpyridine Acetone Acetonitrile Acrolein 1,3-Butadiene, mg Nitrous acid isoquioline Isoamylamine 3-Cyanopyridine Carbonyls Formaldehyde, Acetaldehyde, Acetone, Acrolein, Propionaldehyde, Crotonaldehyde, Methyl-Ethyl-Ketone, Butyraldehyde Phenolics Hydroquinone, Resorcinol, Catechol, Phenol, Cresol (m+p and o) Benzo[a]pyrene BaP (HPLC) Aromatic Amines 3- and 4-aminobiphenyl, 1- and 2- aminonapthlene, o-toluidine, o-anisidine Oxides of Nitrogen NO, NOx Hydrogen Cyanide HCN (gas and particulate phases) Ammonia NH3 by ion chromatography Volatiles Benzene, Toluene, 1,3-butadiene, Isoprene, Acrylonitrile Semi-Volatiles Pyridine, Quinoline, Styrene Trace Metals Nickel (Ni) Cadmium (Cd) Lead (Pb) Chromium (Cr) Arsenic (As) Selenium (Se) Mercury Mercury (Hg) Smoke pH Integrated Puff Profile Tobacco Specific Nitrosamines N-Nitrosonornicotine (NNN) N-Nitrosoanabasine (NAB) N-Nitrosoanatabine (NAT) 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK) Volatile Nitrosamines N,N-Nitrosodimethylamine (NDMA) N-Nitrosopyrrolidine (NPYR) N,N-Nitrosodiethylamine (NDEA) N,N-Nitrosoethylmethylamine (NEMA) N,N-Nitrosodipropylamine (NDPA) N,N-Nitrosodibuthylamine (NDBA) N-Nitrosopiperidine (NPIP) Polycyclic Aromatic Hydrocarbons Naphthalene 1-Methylnaphthalene 2-methylnaphthalene Acenaphthylene Acenaphthene Fluorene Phenanthrene Anthracene Fluoranthene Pyrene Benzo(a)anthracene Chrysene Benzo(b)fluoranthene Benzo(k)fluoranthene Benzo(j)fluoranthene Benzo(g,h,l)perylene Benzo(e)pyrene Benzo(a)pyrene Perylene Indeno(1,2,3,-cd)pyrene Dibenzo(a,h)anthracene Dibenz(a,j)acridine Dibenz(a,h)acridine Dibenz(a,e)pyrene Dibenz(a,h)pyrene Dibenz(a,i)pyrene Dibenz(a,l)pyrene 7H-Dibenzo(c,g)carbazole Heterocyclic Aromatic Amines 2-Amino-3-methylimidaszo(4,5-f)quinoline (IQ) 2-Amino-3,4-dimethylimidazo(4,5-f)quinoline (MeIQ) 2-Amino-3-methyl-9H-pyrido(2,3-b)indole (MeAaC) 2-Amino-9H-pyrido(2,3-b)indole (AaC) 1-Methyl-9H-pyridol(3,4-b)indole (Harman) 9H-Pyrido(3,4-b)indole (Norharman) Nitrogen 280-320 mg (56-64%b) Oxygen 50-70 mg (11-14%b) Carbon dioxide 45-65 mg (9-13%b) Carbon monoxide 14-23 mg (2.8-4.6%b) Water 7-12 mg (1.4-2.4%b) Argon 5mg (1.0%b) Hydrogen 0.5-1.0 mg Ammonia 10-130 μg Nitrogen oxides (NOx) 100-600 μg Hydrogen cyanide 400-500 μg Hydrogen sulfide 20-90 μg Methane 1.0-2.0 mg Other volatile alkanes (20) 1.0-.16 mgc Volatile alkenes (16) 0.4-0.5mg Isoprene 0.2-0.4mg Butadiene 25-40μg Acetylene 20-35μg Benzene 12-50μg Toluene 20-60μg Styrene 10μg Other volatile aromatic hydrocarbons (29) 15-30μg Formic acid 200-600 μg Acetic acid 300-1,700 μg Propionic acid 100-300 μg Methyl formate 20-30 μg Other volatile acids (6) 5-10 μgc Formaldehyde 20-100 μg Acetaldehyde 400-1,400 μg Acrolein 60-140 μg Other volatile aldehydes (6) Acetone Other volatile ketones (3) Methanol Other volatile alcohols (7) Acetonitrile Other volatile nitriles (I0) Furan Other volatile furans (4) Pyridine Picolines (3) 3-Vinylpyridine Other volatile pyridines (25) Pyrrole Pyrrolidine N-Methylpyrrolidine Volatile pyrazines (18) Methylamine Other aliphatic amines (32) Nornicotine Anatabine Anabasine Other tobacco alkaloids (17) Bipyridyls (4) n-Hentriacontane (n-C31H64) Total nonvolatile hydrocarbons (45)b Naphthalene Other naphthalenes (23) Phenanthrenes (7) Anthracenes (5) Fluorenes (7) Pyrenes (6) Fluoranthenes (5) Carcinogenic polynuclear aromatic hydrocarbons (11)c Phenol Other phenols (45)b Catechol Other catechols (4) Other dihydroxybenzenes (10) Scopoletin Other polyphenols (8)b Cyclotenes (10)b Quinones (7) Solanesol Neophytadienes (4) 200-350 Limonene 30-60 Other terpenes (200-250)b NA Palmitic acid 100-150 Stearic acid 50-75 Oleic acid 40-110 Linoleic acid 60-150 Linolenic acid 150-250 Lactic acid 60-80 Indole 10-15 Skatole 12-16 Other indoles (13) NA Quinolines (7) 2-4 Other N-heterocyclic hydrocarbons (55) NA Benzofurans (4) 200-300 Other O-heterocyclic hydrocarbons (42) NA Stigmasterol 40-70 Sitosterol 30-40 Campesterol 20-30 Cholesterol 10-20 Aniline 0.36 Toluidines 0.23 Other aromatic amines (12) 0.25 Tobacco-specific N-nitrosamines (4)c 0.34-2.7 Glycerol PAH Benz(a)anthracene Benzo(b)fluoranthene Benzo(j)fluoranthene Benzo(k)fluoranthene Benzo(a)pyrene Chrysene Dibenz(a,h)anthracene Dibenzo(a,1)pyrene Dibenzo(a,1)pyrene Indeno(1,2,3-c,d)pyrene 5-Methylchrysene Aza-arenes Quinoline Dibenz(a,h)acridine Dibenz(aj)acridine 7H-Dibenzo(c,g)carbazole N-Nitrosamines N-Nitrosodimethylamine N-Nitrosoethyl methylamine N-Nitrosodiethylamine N-Nitrosopyrrolidine N-Nitrosodiethanolamine N’-Nitrosonomicotine 4-(Methylnitrosamino)-1- (3-pyridyl)-1-butanone N’-Nitrosoanabasine N-Nitrosomorpholine 2-Toluidine 2-Naphthylamine 4-Aminobiphenyl Aldehydes Formaldehyde Acetaldehyde Crotonaldehyde Miscellaneous organic compounds Benzene Acrylonitrile 1,1-Dimethylhydrazine 2-Nitropropane Ethylcarbamate Vinylchloride Inorganic compounds Hydrazine Arsenic Nickel Chromium Cadmium Lead Polonium-210 Asbestos Plutonium

SORRY - that was also a mistake. The above is NOT a list of the inactive chemical ingredients in e-liquids. It is a list of the inactive ingredients that have been detected in the smoke from cigarettes, also approved for sale, marketing, and inhalation by the FDA.

Here is the actual list of chemicals in the flavoring components found in e-liquids, which have not yet been approved for sale by the FDA:

Vanillin, maltol, ethyl maltol, ethyl vanillin, benzaldehyde, p-tolualdehyde, benzyl alcohol, limonene, ethyl butyrate, ethyl acetate, gamma-undecalactone, menthol, eugenol, 2-methylbutyl acetate, cinnemaldehyde, ethyl hexanoate, menthone, piperanal,  carvone, methyl anthranilate, ethyl isovalerate, hexyl acetate, hexenol.

My point is four-fold:

1. The chemicals in electronic cigarettes - the "inactive" ingredients if you will - are not dissimilar to inactive ingredients in many pharmaceutical inhalers that are approved by the FDA. The chemicals in those inhalers are known to cause respiratory irritation. Yes, it is true that some of the chemicals in the e-liquids, especially the aldehydes, could cause some mild respiratory irritation. However, there is no reason to believe at present that the degree of respiratory irritation is substantially different than what occurs with the inhalation of approved FDA drugs.

2. The chemicals detected in e-cigarette flavorings present an extremely low level of risk when compared to the chemicals in tobacco smoke. The difference is essentially between a behavior that results in destruction of the lungs and a behavior that may cause, at the worst, mild respiratory irritation. Let's keep a sense of perspective here. Most of the individuals who are regular users of e-cigarettes are former smokers who have quit or current smokers. In either case, switching to vaping is the most important thing they can do to protect their health, assuming they are unable to quit nicotine use completely, which is probably the case for most vapers (that is why they tried vaping in the first place; had they been able to quit cold turkey, they would have).

3. One cannot necessarily draw conclusions about human health risks based solely on looking at a list of ingredients. The dose of exposure is critical. We do not know enough at this point for anyone to conclude that the flavorings in electronic cigarettes pose a significant risk of substantial adverse health effects. Moreover, there has been enough short-term use of these products for us to feel somewhat confident that we are not observing acute toxicity due to these products. Any potential risks would likely be very long-term. And we don't even know yet whether it is possible to sustain vaping for the 20 or 30 years that would be necessary before any respiratory irritant effect would translate into clinical lung disease, or if anyone would want to do that.

4. Remember that e-cigarettes are recreational products, not pharmaceutical products. The critical concern is not their absolute level of safety, but their relative level of safety compared to real cigarettes. The analysis presented in this paper is actually reassuring, because it provides irrefutable evidence that e-cigarettes are much, much safer than real ones.

Before closing, let me make three important points.

First, although I don't think a health scare over the flavorings in e-cigarettes is warranted, I do support reasonable regulations and safety standards to minimize any health risks from e-cigarettes. And I do support full disclosure of ingredients. So I actually agree with the article's ultimate recommendation that the ingredients of e-cigarettes should be listed for the consumer and that the FDA exercise some reasonable degree of regulation over the flavorings. But clearly, a ban on e-cigarette flavorings is completely unwarranted.

Second, there may be a few select flavorings that absolutely should not be used in e-cigarettes. Dr. Farasalinos has made a compelling case that diacetyl should not be used as a flavoring because of its known potential for severe respiratory effects. It would not be unreasonable for the FDA to promulgate a list of a few select flavorings that should not be used in these products, nor would it be unreasonable to restrict the total percentage of flavorings to some reasonable proportion of the overall e-liquid.

Third, it is worth noting that two of the authors of this paper are co-authors on the paper which concluded that vaping is more hazardous than smoking based on high levels of formaldehyde, levels that resulting from the severe overheating of the e-liquid producing dry puff conditions under which no vaper would continue vaping. The apparent bias of these researchers against e-cigarettes should be considered in interpreting the results of the study.