There are many things that could be considered a damaged fireplace. There can be creosote that has built up in flue and when you go to light a fire in your fireplace the creosote catches fire and can then extend inside the house. An improperly installed gas line can be a hazard because you could have gas exhausting right into your living quarters. Capital Chimney Corp. suggests having your fireplace and chimney inspected at least 2 times a year. A simple chimney sweep can save your life!