Some of y'all poo-poo NBC gear, saying you'd rather not live through such things...But, living in a very urban environment, I can fore see several possible, temporary events that such gear would help me get through:
> Toxic smoke from massive urban fires, or even factory fires.
> Chemical spills from factories.
> Chemical spills from train derailment (a major concern at my location.)
> Nuclear reactor meltdown. If you can keep the radioactive particles out of your respiratory system while escaping the area, you will most likely make it through the situation relatively unscathed.
> Whatever air-born super-bug "they" decide to release on us to thin the heard.
Besides gas masks, I also have half-face respirators with the multi-use cartridges.