Creosote is a black, sticky, tar-like material which builds up in chimneys from the burning of wood. When fuel doesn’t burn completely, smoke cools as it rises through the flue, causing unburned particles to condense and cling to the chimney walls. Over time, these deposits harden and continue to build up. It can be a severe problem to build up creosote. Maintaining a clean chimney is essential not only for heating efficiency but also for protecting your home and family. If creosote is not removed from a chimney, a nice fireplace could become dangerous quickly. Dangers of Allowing Creosote to Accumulate Neglecting the accumulation of creosote can cause serious safety risks like chimney fire damage. The ignition of flammable creosote can occur when there is a spark or some high heat in the chimney. A high percentage of chimney fires that cause house fires are the result of creosote according to fire safety data. A chimney fire can crack flue liners and damage masonry, allowing flames to...