Lumber purchased from a hardwood store won’t be treated with anything. The only woods I know of that are treated for any reason are construction grade materials. You’d be hard-pressed to find a fine woodworker who’s willing to use treated woods. I worked at a high output hard wood store for years, and the only woods we sold that were treated with anything were plywoods and the like.
Whatever the case, I don’t think any kind of sawdust should be inhaled whenever it’s avoidable. The toxicity of the wood is almost negligible unless we are talking about something extremely toxic, or irritating to the skin( such as walnut). A simple dust mask negates the risk factor.
First off wood treated at the wood mill and not the lumber yard/ hard wood store.
Yes they still are treated, they just cut back on the formaldehyde due to recent US regulations.
Chromated Copper Arsenic (the most popular and common chemical used) still used as its a preservative in building materials, it keeps wood fungus and insect free.
General exposure to this wood isn’t a risk (its safe to build a play ground with) but working with it still requires plenty of ventilation.
It is required for international exports and at higher concentrations to avoid accidentally introducing new invasive species.
Not sure if you’re saying they are, but hardwoods aren’t treated. They are kiln dried, thus eliminating any threat of exporting fungi or insects. The exception would be laminations and flooring materials, but if you go to a hardwood store and buy a plank of mahogany, it won’t be treated.