Thanks for the sentiments, guys. I get by okay, just no longer can do much physical activity. It is ironic how I used to talk to World War I veterans about getting exposed to mustard gas in the trench warfare, then wound up now in the same condition as many of them (the lucky ones that only got a whiff or two).
But I knew the risks on that project, and got paid extra to take them, but I do wish I could say a few words to that Army guy who told me "go ahead in, that old building is safe because we tested it out completely". It makes one have sort of a skeptical nature! If I could get a do-over, I would go ahead and put on the gas mask that I had strapped to my belt, no matter how many tests had been made.
7 or 8 years later I was on the team that was hired to decontaminate and dismantle that same building and equipment. Using later testing devices, the mustard level was found on 90-degree days to be 60 PPM, while the safe level was considered to be the minimum level that could be detected, about 3 PPM as I remember. By that time I had become a programmer and wrote a PLC5 program to run the system that heated up the entire building to 400 degrees and cycled and filtered the air for 2 weeks.