@kenmcchord just posted (#18446) about chips and varieties of wood on the thread What I Did For Beer Today in the General Home-brew Discussion. He may be helpful. Some other posting that follow his also address your interest.
Hi,
I have plenty of scraps, be happy to mail you some cherry if you like. I know for fact the wood has never been sprayed, painted, treated nor any other unhealthy treatment. I do not have any chestnut but I do have some oak cubes I just toasted up today in my oven. Check out the post (#18446) that @D.B.Moody mentioned above, you can see plenty of photos I took of the process.