[rotorwrench]

I still use a respirator type that has the straps that pulls over your cranium and the back of the neck. They work very well when they are rated for fumes such as polyisocyanate. They never used to put use by dates on them 30 or 40 years ago. I used them till the straps gave out then I buy a new one. I also had gas mask training in the army and the surest way of telling whether the mask will work or not is to spray up some fumes and see if you can smell it through the mask. If you can smell the fumes, then it's not working.

Now days, the new masks I buy come sealed in a bag and are all completely assembled. I haven't looked for a "use by date" but I'm going to use them till its worn out like I always have. I've know several guys who worked for years without respirators until the polyurethanes came out and most of them lived long lives. The guys that smoked, well that's a different story. Union Carbide was pretty much wiped out by that fiasco.

That deal with Union Carbide in Bhopal, India was a bad one. A major leak of methyl isocyanate & other gasses happened at night and the stuff spread along the ground since it was heavier than oxygen/nitrogen air and the folks that lived around that plant had no warning of the leak. They were making it in India due to the lax laws in place there. Mix that with lax training and security around a major pesticide production plant and that spells disaster and that's what happened. The folks never woke up. With the density of population, it was no wonder they had around 16,000 casualties and most of them died. No telling how many had lung ailments among the survivors of the 600K folks that lived around there. The plant warning system worked but the public warning system didn't due to poor maintenance.