How is this different from plywood or pressure treated wood (used mostly outdoors) or carpeting or any other building material that isn't either plain metal or a "all natural" product? Modern building involves chemically treated stuff. As far as OSB specifically (similarly, non-finish-grade plywood), I would not expect to see it in a house except in an unfinished basement, garage or workshop - any place else it will normally be covered with something else, at a minimum primer + paint.

The question is asking about OSB specifically because my interest is in OSB specifically. Indeed, similar questions can be asked about plywood and other materials which also contain formaldehyde or similar chemicals. If anyone would like to know the same about plywood or something else, they are welcome to make another post, and can even link to this one for reference.

For this question, I am looking for answers for OSB only, not plywood, carpet or other materials.

I would not expect to see it in a house except in an unfinished basement, garage or workshop - any place else it will normally be covered with something else, at a minimum primer + paint.

This is why in the question, I stated that it will in fact be left uncovered, and I am asking specifically for that case. I know people "normally" do cover it, but the question is about the chemical properties of OSB, not about home decoration. I'd prefer to avoid going on a tangent to debate everyone's preference on the best way to prime/paint/cover OSB (although feel free to post a separate question if you'd like to).

If the answer is "it does release harmful vapors if you don't paint it", that is acceptable.

Not bothering to run this down to a source right now, but I believe that exposed OSB is a possible fire code issue. I also doubt that painting or drywalling it does anything to limit offgassing.