The entire range of Pureflame’s portable fireplaces will burn a plant-derived ethyl alcohol biofuel that they call Purefuels. According to Pureflame, the fuel is “non-toxic, smokeless, odorless and environmentally friendly” – where steam and carbon dioxide are released as it burns. No, you will not suffer from a lack of oxygen if Pureflame’s chemical engineering got the ratio mix just right, where the steam and CO2 released are in proportions similar to those given off by people as they exhale. One quart (0.95 liters) of the liquid is said to deliver anywhere from two to five hours of burn time – I suppose environmental factors also play a role in the length mentioned. You can choose from four different models, where they are priced between $649 to $879.