Good morning Chris.
I can't say that I have experienced any difficulty. I have not heard of any problem with cottonwood dust. I also have to say that I do not create much dust with the cottonwood, no sanding, no power tools, so very little dust.
I am not the expert to ask. And I too would be interested in what others have to say. I have heard of some of the wood you mention and their danger. Now I am going to look for a thread on dangerous woods and dust.
Rick Jensen would be someone we want to kick in on the cottonwood. He has done it for many years. Or is someone going to pitch in and tell us that explains Rick and his behavior to them. {{Rick, we really do like your work

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That's the best I can do for you Chris. Hope you find answers and a good piece of bark.
Thanks for looking.
John K Karver