Based on the “Getting Insulation Out of Your Walls and Ceilings” article (and similar to the PERSIST/REMOTE wall design), in my plans I’ve moved rigid insulation to the outside of my air barrier (which is at the sheathing layer) and the left stud bays empty.  For an interior finish I’ve used two layers of white pine with overlapping seams on the interior of the studs.  The sheathing I’m using is Zip System OSB (taped).

My concern is this: A couple of weeks after putting up the zip system boards, I’m still smelling the zip system through the white pine.  I’m guessing the smell will subside over time but I also have health concerns: if I’m smelling it, surely I’m breathing in chemicals that are in the zip system material.  I cut the zip boards outside and was careful to wear a P100 respirator while cutting and fastening them (which hopefully worked–I didn’t smell the material at all while using the mask).

I tried looking into this a bit and from what I can tell I don’t really have any reason to be concerned, especially if it’s going to be a while before I move into the structure.  My “question” is really whether or not I’m interpreting the data correctly and not missing anything.

First, it seems the out-gassing chemical of concern is formaldehyde (at least this is what the resources I’m reading seem to focus on).  Huber uses phenol formaldehyde in its products instead of urea formaldehyde (https://www.huberwood.com/uploads/documents/technical/documents/Formaldehyde-in-AdvanTech-and-ZIP-System-Panels-Technical-Tip-Roof-Wall-and-Subfloor-ZIP-System-and-AdvanTech.pdf) which tends to out-gas less and subsides to undetectable levels over the long term according to https://www.roseburg.com/UserFiles/Library/APA_Tech_Bulletin_on_Formadehyde.pdf 

According to APA Technical Note J330

https://www.apawood.org/download_pdf.ashx?pubid=2962e0a8-596d-4df7-96e0-cdeebade8647), the emission level of 0.2 ppm under the ASTM E1333 Large Chamber Test method appears to be the limit specified by the US HUD safety standard, and typical plywood and OSB products range between 0.01 and 0.04 ppm.  Zip System OSB ranges between 0.04 and 0.05, so it’s on the high end compared to other products but still well below the limit https://www.huberwood.com/uploads/documents/technical/documents/Safety-Data-Sheet-Wall-Roof-and-R-sheathing-ZIP-System.pdf

All of this taken together leads me to think that if the structure is left to out-gas for a while I don’t really have anything to be concerned about.  But perhaps I’m missing something or interpreting the information incorrectly–I’m prepared to take all of the OSB down if they’re a health risk (though I don’t know of a good alternative–there’s Purebond but that’s not intended for structural use)