Snap 'n startt. Snap apart to have a rough edge to light. These wood-wax fire starters are made from wax and sawdust. If your fireplace is functioning properly, emissions of this product should be vented outdoors. A properly installed and maintained fireplace and chimney will dramatically reduce the likelihood of combustion by products entering your home. An inadequate air supply or a downdraft could cause a fireplace malfunction. If you suspect that your unit is not functioning properly, a qualified contractor should be consulted. Warner hersey: for use in solid fuel burning masonry fireplaces, listed factory built fireplaces, and fireplace inserts. Warning: use only one firelog at a time. Underwriters’ laboratories: classified – processed solid fuel classified for use in factory-built fireplaces. Domestix. Unconditional guarantee.