Question: I have seven coal burning fireplaces in our circa 1886 home. I have read some of your answers about burning coal in fireplaces (using soft coal). I would like to use these fireplaces but the flues have no liners in them. The chimneys are in good shape and I was told by my chimney sweep "off the record" that if it were him, he would burn coal in them since there is not much heat, and no sparks. Is this ok considering the byproducts that I understand coal gives off? I've also found places that have gas coal-looking fireplace setups. Would these be ok to use in an unlined flue in good condition? These chimneys are about forty five feet from fireplace to top and have excellent draft. Answer: Coal does put off a large amount of CO (Carbon Monoxide) which is very deadly. If the flue is not tight this could leak into the home. You can purchase smoke test candles from several internet & specialty shop outlets and test the flues for leaks. If the flues are very sound, then coal might be OK as is. The gas units will probably also be fine...if they are simply the open vented logs. If they are vented gas inserts they probably need an aluminum liner from the appliance to the top of the chimney.