Has anyone out there had personal bad experiences with burning untreated 2x4's etc . . . on a fairly regular basis? Or even anyone that has seen someone else have negative effects to their stove? I have a new Hampton EPA insert and I'm in construction, so I have access to a lot of free scrap. I've read that even "untreated" lumber might have been dipped in fungicide, or floated over salt water, the byproducts of burning which might corrode your stove. On the other hand I read in this Fine Homebuilding article : http://www.finehomebuilding.com/how-to/qa/dangers-of-burning-plywood.aspx "The only studies I could find comparing combustion emissions of natural wood vs. manufactured wood showed very little difference between the two. A study by researchers at the University of Wisconsin and the U. S. Department of Agriculture Forest Products Laboratory in Madison, Wisconsin, looked at total hydrocarbons, formaldehyde, total aldehydes and carbon monoxide emissions from burning natural aspen and aspen flake board. The study simulated industrial boiler-firing conditions with high combustion temperatures (1,500° to 2,400° F) and increased air supplies." This study references flakeboard, which is analogous to plywood, and found that if burned at the proper temperature, you can barely distinguish between the exhaust of manufactured wood and natural wood. Now, I'd never burn PT because of the arsenic and other bad stuff, but maybe some plywood isn't all that bad? And yes, I know how to avoid over-firing my stove.