Compiled EC50 values (% volume of e-liquid) by flavor categories. “Flavorless” e-liquids include Flavorless (Vapor Emporium), Clear (Mister-E-Liquid), and Flavorless (Vape Dudes). “Coffee” e-liquids include Irish Latte (Lotus), G.T.F.O. (Mister-E-Liquid), and Irish Coffee (Vape Dudes). “Fruity” e-liquids include Sweet Melon (Lotus), Watermelon (Mister-E-Liquid), Watermelon Drip (Vape Dudes), Mango Blast (Lotus), XXX Berry (Lotus), Heartbreaker (Mister-E-Liquid), and Possum Sauce (Vape Dudes). “Menthol” e-liquids include Menthol (Lotus), Mister E’s Menthol (Mister-E-Liquid), and ICE ICE (Vape Dudes). “Cinnamon” e-liquids includes Fireball (Lotus), Napalm (Mister-E-Liquid), and Cinn Candy (Vape Dudes). * denotes significant difference when compared to the flavorless category within a cell line (p <0.05). † denotes significant difference when compared to same e-liquid treatment in other cell line (p <0.05).