It's a bad old world, and you have to read up and closely inspect the product. Cowboy doesn't seem to be able to say how plywood got into their wood recycle stream and ended up in the charcoal. I find that odd, and it makes me suspicious of claims that wood is all unfinished and untreated.
You really can tell a lot about the wood source from inspecting the lumps. If it's flooring, the milling joints give it away. Small sticks with square corners are likely from furniture operations. A predominence of ragged, random shaped chunks speaks of virgin logs. I like those. It's just too tempting to let treated and finished wood enter the stream. I mean, this has to be a narrow profit margin affair, and I don't see anyone getting too upset or taking any action when the shop employees find it easier to throw everything into the "virgin" recycle bin, rather than haul it to the other. And note those that have been found to have kiln insulation mixed in. Those are refractory wools, fiberglass and other materials that you would prefer to avoid in your food. No doubt the kilns need constant maintenance in the form of patching with wool and refractory cement.
For those in Texas, HEB oak lump is consistently well spoken of. Big Green Egg is said to be good and is probably made by Royal Oak, which seems to be also good. The analysis of how much of the bag was dust and unusuably small chips is good.
"Kitchen duty is awarded only to those of manifest excellence..." - The Master, Dogen