very well could be an employee of the EPA or OSHA with a small testing dosimeter or other gear, checks the levels of lead in the air to verify the ventilation system is working properly. Not a big deal for me or you to walk down range once in a while but imagine doing it every day several times a day. Sort of like in the Marines when they decided to take the old insect repellant away from us, I boxed it all up and gave it to a guy in a haz mat suit. Same thing, not big deal for me to handle once, but for the guy that takes them in by the thousands..... same idea I am guessing. IMHO.
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Marine, Retired LEO, Firearms Instructor, Life Member NRA Tea Party Member, and general all around trouble maker.