Where is the sawdust coming from, meaning is it coming from where they initially are sawing the logs prior to any type of stain, varnish, etc being applied or is it coming from where they are sawing it to floorboard length afterward or both? Some hardwood flooring comes prestained and varnished before it is shipped to the contractor. Some is not. Also, ask if they are manufacturing the pellets on site or are they shippng their sawdust to someone else to make the pellets for them. If they are shipping it elsewhere ask them if they will tell you to whom they are shipping and where they are located. One final question, is it a 100% flavor wood pellet or is it a blend such as a 70% base wood and 30% flavor wood.