Isocyanate poisoning is about the worst thing you can experience. Think of lighting a carton of cigarettes, putting all two hundred in your mouth at once and taking the biggest puff you can. And that's a mild case. I've spent fifteen minutes on the floor puking my guts out, vacuuming my lungs with each puke, and couldn't stop shaking for a day. Again, that's a mild case.
VENTILATION! You want to make sure this stuff is taken away from the project (and you since you're in the way) as quickly as possible. Get yourself a full face mask with NIOSH approved filters. None of them will be approved for isocyanates, since they really want you to use a fresh air set up. But make sure you have a good fan system to pull crap away from you. And filter it. Not good for your neighbors to be breathing it in.