What are Soot and Creosote? When you burn wood in your fireplace, it produces a number of byproducts including ash, smoke, soot and creosote. Soot is a black powder that is largely comprised of unburned materials. This creosote is incredibly flammable and can create a very hot fire that ignites within your chimney.Click to see full answer. Herein, is soot flammable?Soot refers specifically to the fine, black, carbonaceous (carbon-containing) particles produced by incomplete combustion of an organic material. Soot can contain carcinogenic compounds such as polycyclic aromatic hydrocarbons and is a flammable material, so treat it with respect! how do I know if my chimney is on fire? You may detect: A loud, crackling or popping noise from the chimney flue (imagine the sound of a large bonfire) A lot of dense, thick smoke coming into the fireplace or out of the top of the chimney. Flames or things that are on fire (pieces of flaming creosote) coming from the top of the chimney. Also Know, is chimney soot dangerous? Like creosote, if chimney soot is inhaled in great enough amounts, it has the potential to either irritate the lungs or cause lung diseases. Respiratory Risks. In conjunction with lung problems, general respiratory infections may crop up due to soot inhalation.Is soot poisonous?Soot can enter your body through inhalation, ingestion or via the skin and eyes. These toxic particles can cause breathing issues, including asthma, bronchitis, coronary heart disease, and even cancer. Infants, the elderly, and those who already have breathing problems are the most affected.