Ethanol (Bio-Ethanol) Fuel burns clean without emitting any harmful toxins into the air, with only harmless water vapor produced as a byproduct and a small amount of Carbon Dioxide. Make sure you ONLY use liquid bio-ethanol fuel for fireplaces, as any other kind of fuel can emit harmful toxins or be unsafe. Ethanol fireplaces do produce real flame, so any common sense precautions apply when it comes to pets and kids.