Here is something. Did you make this in your garage? What temperature and humidity did you use it in? I see you live in Utah and I imagine its a lot colder than here. I live in San Antonio, Texas and I build vivs year around (part-time). THE single biggest issue I've noticed regarding the proper cure of the literally 100's of different materials I've worked with, designed, and experimented with, is the ambient temperature/humidity. I live/work at night just to combat this single issue as the only time temperatures ever stabilize around here is from about 10pm-5am during the summer. During the winter I keep the garage closed and use heaters.
Possible reasons you are having issues with this:
1. Your temperature/humidity levels are not in the appropriate ranges for the foam to cure. The fastest cure I've ever had with GS foam was in a rainstorm in Hawaii. 100% humidity, 85F. Full cure in less than 20 minutes. (I was using it as a mother-molding material for some molds I was taking off banyan tree roots.)
The colder the temperature and less moisture in the air, the less C02 is produced and less expansion you get, resulting in a higher density foam and an sort of pudding/frothy/melted ice-cream look.
The problem this can cause is that if the amount of moisture that comes in contact with the material is not enough by the time the outer layer skins, the areas underneath do not have enough moisture to fully react. Adding to that the skin prevents almost all air/water movement.
This is dramatically exacerbated if coupled with spraying large volumes as this creates deeper areas.
2. The cans you are buying are bad. The batch/source/handling/shipping whatever is not correct. One of the biggest issues with polymers in general is their freeze/thaw stability. Some are no longer stable or in the same configuration after a freezing event. Sometimes its just as simple as shaking the can to mix it again, but other times it has permanently deteriorated the polymer. PUR foam, I think is one of the later, but as you are seeing at least partial cures, this could be ruled out to a point.
3. User error. You are not shaking the cans for 2-3 minutes like they say and/or you are using too large of volumes for the ambient conditions to allow for.
4. Your sense of smell is 50-100X greater than the rest of us.
My guess is its too cold, too dry, and you are using too much at a time. Also check the expiration dates of each can EVERY time. This is a HUGE issue with GE silicone too.
As for the GAS being toxic I've got varying degrees of agreement with that. An animal in contact with air that has that gas in it will likely not kill/damage it. Too dilute. However what the gas originates from, could be an issue IF it is allowed to come in contact with water and THEN that water comes into contact with the animal. Assuming it is not a water-cured material that would become inert after reacting with the water.
One fix you can try is soaking the crud out of the thing with a hose. Poking holes will help.
