Just to add another angle. Since a specific application wasn't mentioned by the OP, there's one scenario I have contemplated for using an OC fogger.

For a burglary/home invasion-type scenario where your plan is to shelter in place until the police arrive, if you have time, a fogger could be discharged in the area outside your safe room to discourage someone from coming that way. Or perhaps discharging it in the stairwell leading up to the second floor or some other confined chokepoint. Obviously, it's only a deterrant, but if they aren't too motivated to get to you, it could do the trick.

And from a legal standpoint, I would think that someone who endures an OC filled hallway to get at you bolsters a self-defense case. They are probably incapacitated to some degree by the time they get near you, too, especially if they're breathing in that fine OC aerosol.

It would suck to decon your living space afterward, but that's a small price to pay if it works.