As discussed earlier, the potential reduction in toxin exposure to the lungs from any product primarily delivery smoke from burned tobacco is very hard to quantify. Human lungs are not built to breath smoke, and so combustion products are likely to be extremely harmful no matter what tinkering is done with the smoke chemistry. These products would be just as likely to be a repeat of the Light Cigarette experience in which many people switched in the unfounded expectation of having lower health risks.