text: why does fire need air and oxygen to burn.?   without air, oxygen, and fuel, as rightly as someone has posted as an answer before me, a fire is nonexistant. a fire is the chemical reaction itself caused by those materials.  there is no such thing as fire without air, oxygen, or fuel.  p.s. perhaps there is some laboratory special fire made with a different fuel or something, but other than that, absolutely no possible exceptions.  nice question.