for those still following this thread,
Exterior grade plywood, at least in the US, uses phenyl formaldehyde, interior grade uses urea formaldehyde
Interior grade will quickly delaminate and eventually decompose as the binder is water soluble. Exterior grade will eventually degrade after exposure to water, sun, microbes and the like.
Formaldehyde in it self is a huge family of chemicals and not necessarily "bad" chemicals. The smell of fresh cut grass has formaldehyde compounds in it. The smell of hay/straw bales too.
The use of sawdust and chipped plywood needs some caution. I would not be using it among crops I plan to consume, though as sheet mulch component to choke out weeds, I would use it.
Never burn it!
Other treated wood products have no business in compost or mulching operations. Avoid those at all costs. You cannot determine, easily, if the lead content is at dangerous threshold, same for other preservatives with copper or arsenic.
again NEVER BURN IT!
Boric acid compounds are water soluble, purported to be non-toxic to higher order animals and not for use in ground contact lumber. In a chipper/compost operation, I expect this would compost more slowly and have minimal, if any, measurable impacts. If you are working on certifying your operations as ORGANIC, keep this out of your piles/mulch.
I am working on protocols to address debris from construction projects. Wood in particular is an issue in CA as we no longer have biomass electrical generation as an option. On site composting is the avenue I am pursuing right now.
