WMD Equipment: Respirators
First, the best respirator is called a Positive Pressure-Demand Self-Contained Breathing Apparatus (SCBA). Commonly used by Firefighters, it consists of a mask attached to a tank of air through a regulator assembly. Notice that I say best respirator, and not best option. This is because, even though the SCBA offers the greates Protection Factor "PF", it does so at a great weight, space and time penalty.
In most circumstances (those where the hazards are known, there is an adequate supply of oxygen in the air, you are not in a confined space, and you are not working at the seat of the incident immediately post-blast), the best type of respirator is an Air Purifying Full-Face Respirator. All respirators are not created equally.
I do not recommend half-face respirators, because too many things can be absorbed by your eyes, and a mask/goggle ensemble doesn't work. I also don't recommend escape respirators for many reasons. As of this writing, none are certified to resist a WMD environment by a competent authority for any reasonable length of time. How fire resistant are they? How do they address the buildup of Carbon Dioxide that occurs in that bag? And, if they are 'just as effective as current US Military masks', why haven't they replaced them? After all, they are more inexpensive. Finally, how do they seal around the neck snugly enough to resist WMD Agent entry as I look up and around, but not choke me?
Apparently, others agree, as the CPSC has ordered a recall of one and assisted in the voluntary recall of another escape mask.
I also highly DO NOT recommend any used respirator. Period. This even extends to new civilian defense masks from Israel, China, Russia, Egypt, Canada or wherever. And especially anything bought off of an Internet Auction site. Why? I could devote an entire article about used respirators, but the biggest reason is this: What are you REALLY getting? You are investing money in an item that MUST protect you against items one micron in diameter. (An average hair on your head is about 50 microns wide.) All plastic items degrade with time, especially in joints and flexed areas. A hole smaller than can be seen with your eye can kill you. Remember, as you breathe in, you create a vaccum as you pull against the resistance of the filter. One teeny dry-rotted hole, and there is a lesser path of resistance.
Secondly, with age, comes obsolescence. That's a fifty-cent term that means the manufacturer stops making parts for the item. For instance, nobody makes a current NBC-rated filter for the M17 series of respirator. And, because there is an active element in the filter system, there are no filters, unopened or otherwise, that will protect you from a WMD attack. This also applies to the other older used masks. That cannister you bought that might have been good in 1980 is dead now.
In closing, don't skimp on a respirator. Buy new, get new filters, and have someone help you learn how to properly use the mask. Like the old vest adage, don't be caught dead with a used mask!