In article , says...
For Norm's benefit. Tanalith is a UK trade name for the treatment chemical
used when pressure treating timber. It's generic name is CCA which is Copper
Chromium Arsenic. Those are the active ingredients. They are perfectly
stable once they have dried into the woods cellular structure. However,
pressure treated wood should not be burned for disposal. I would also advise
against eating it. That may not be a likely thing for you and I to do but
don't make children's toys or dog kennels out of it.

John

The CCA treated wood will not hold paint well until it is dried out.
Normally in the US this stiff is sold in a very wet condition and does
not paint well.