Oh yeah I'm familiar with Dichlorvos (main ingredient in NPS). I've used it in the past in reptile rooms to keep mites away (when I bred and raised Green Tree Pythons), and used it in the past to keep fungus-nats away. As long as the room is ventilated, you don't touch the impregnated strip (there's a plastic shield around it), and you don't use multiple strips in a contained area; you're fine.
Now I used 2 strips in a non-ventilated area for a 12 hour time period (then removed a strip) and used a respirator (just incase) when re-entering that room (the room wasn't totally enclosed so I don't think I was in any harm to begin with, but safety first), before turning back on all the ventilation. I did a couple hours of research on the best approach to treat the mites and the strips seemed like the best solution for my scenario (1-2 pest strips for 2-3 days with little to no ventilation). Since I'm so far into the flowering time and have a small enclosed space; spraying neem oil, bombing, or using a sulfur burner, are not really ideal treatments.
Dichlorvos also breaks down pretty rapidly, so I'm not too worried about residual residue or the plants being poisoned and causing phytotoxicity. These strips are toxic if you're an idiot and handle the strips with out their protection and start deliberately huffing the fumes straight out of the bag, but then there are warning labels on just about everything.