Butane combustion yields CO2 and H2O as by-products, which is naturally around you at any given moment. Opening a can of soda will also produce similar by-products. As long as there is a flame, butane is burning away. Butane in lighters is burnt off as the flame ignites. This is especially true with torch lighters, which tend to burn off all butane much better.
Above all, our Vapor Stone is made from a NASA grade ceramic, it will help filter anything harmful, remember the flame should never touch the stone for proper use. Using any other large torch to heat up a banger will produce 3x more by-products than a triple flame torch.
Please do your own research and educate yourself. HealthstoneGlass.com does not make any claims of health benefits. The above statements are based on 3rd party research taken from various trusted sources.