"Frank" wrote

Probably no worse chemicals than the wood itself. I'd burn it.

Here's a guy without a clue.

Not clueless. I'm a retired chemist. If wood is typically bound with
phenol resins, there is no harm in burning and combustion products are no
worse than burning pure wood. If it contains preservatives such as
arsenicals or chlorinated compounds or flame retardants of a similar
nature, it is best land filled.

I think the issue is he doesnt know if it was treated for exterior uses or
not. Case of 'if in doubt, throw it out'.

I found it intriguing that another uses such in his furnace. I imagine all
vapors vent outside so this might be sorta 'ok'?