Before they relocated to Ft. Leonard Wood in MO, the Army's Military Police and Chemical schools were at Ft. McClellan, AL. When I was a student at the MP Officer Advanced Course, we got (had?) to go through the Chemical Defense Training Facility (CDTF) where live chemical weapons were used in order to train with detection and decontamination equipment.
Needless to say there was a lot of prep one must go through in order enter, including giving a blood sample to be used as a baseline for evaluation in case one was accidentally exposed. We were all thoroughly indoctrinated with the list of symptoms to be watchful for after attending the training and advised to get to the post hospital at the first sign of onset. One of these symptoms was headaches.
The only problem with listing that as a symptom was that every student was going to develop headaches because it was a natural impulse to cinch your protective mask on as tight as you possibly could.
Even with all of the safety precautions, we had to pee in a cup on a regular basis to check for mercury poisoning.
I don’t mind wearing a mask to enter a doctor’s office, etc. but down deep inside I know they are more or less useless. The ONLY way they might help is if somebody sneezes right in your face and you replace it immediately without touching the cloth.
Even I have to laugh at some of the masks I see on people’s faces while they think they are protected. They are thin cloth worn below their noses while gaping at every edge.
I sewed about 100 to give away when this all first started but mine were double thicknesses with pockets for filter material and the way I put the ear loops on pulled the cloth tighter around the face. I even put nose clamps in them. The hospitals that were asking for them had certain standards. If I gave one to an individual, instead of a medical person, I warned them to get something better as soon as they could. This was when they were required but nobody could find any commercially made. The hospitals and doctor’s offices wanted them to wear over the medical masks for more protection.
Now that we know more, we know that it wasn’t as deadly as we were told. People work in environments a lot more deadly than covid.