It is clean fuel. But you need a lot for it to last. That’s annoying, especially for it’s price. I have a 3 burner fireplace. You have to use 1 bottle per burner just for it to not go out a few minutes after you light it. No bueno. 2 stars for it only lasting a short time. But 1 extra star for it being a clean smoke free burn. Won’t purchase this again. I will look for a thicker fuel.