The major problem with creosote is that it is highly inflammable. Its accumulation on the flue walls increases the risk of house fire considerably. In fact, thousands of house fires are caused by creosote build-ups in chimneys every year. Fire is one of the most serious perils which can affect a home. It poses extreme danger to people and property. Another problem with fire starting due to the combustion of creosote is that this substance is toxic and can cause serious irritation to the skin and eyes and possibly mental confusion.