According to Cshenk :

"SteveB" wrote

We have lumber scraps left over from construction. Some are pine odd
lengths, some treated pine, and a bunch of particle board.

I know NOT to burn treated lumber.

I've never done it as I've always heard that. I presume the fumes or
something?

CCA lumber, when burned, generates various arsenic compounds in the
air. Including Arsine which is hideously toxic.

I THINK that untreated regular pine will burn fine in our backyard fire
pit.

Yes, as long as you arent dealing with a chimney flue and cresote then it's
ok. Sparks alot though.

What about particle board? I know it has glues in it, and think it
probably should go to the landfill, but thought I'd ask youse guys.

If I didnt know what was in it, I'd be hesitant.

The glues will outgas various things, many of them not altogether
good for you. Amounts will vary depending on fire temperature etc.

Should not be burned.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.