Unlined or damaged liners within chimneys Can be very dangerous in the event of a chimney fire. In today's construction a masonry chimney is supposed to be lined with an approved liner. The liner should have no cracks or separations throughout its entire length. It is recommended that you not use a fireplace with an unlined or damaged chimney have it relined or repaired before using. Stainless steel or fireclay liners can be installed in the chimney. Consider removing and replacing the entire fireplace and chimney if the cost is comparable especially if the existing fireplace is inefficient, smoky, or has a damaged or outdated face. Contact a fireplace specialist or a chimney repair service for assistance.