Thank you for this link. I hope everyone reads it.
Many years ago now we had a presentation at a woodworking group I belonged to and it was dealing with pallet wood. The take away was don't even think about using it for projects. Yes it is tempting but after hearing what I heard I will never ever do any project using it. The one except would be if it were a new pallet and I knew it was new.
At the time PCB's were a big deal, you can look them up but they were contained in all sorts of things often in an oily substance. Clean up efforts proved to be expensive and often after a clean up they would reappear at least in some cases it was due to pallet wood that had come in contact with them on the floor or been dripped on or spilled on and then tracking that stuff all over the place. The contaminated pallet would leave one place by truck and commentating the truck etc etc. I haven't heard much about PCB's of late so I guess that scare is over for the most part but it doesn't mean there is not something else on a used pallet that could be just as bad.
Sorry but every time this comes up I feel that I need to post this sort of information but it is your health during the woodworking phase and then to who ever uses it after that. Free, well there might be some strings attached due to health issue so keep that in mind.
Ed