My father used dynamite in his work (geological exploration). He was susceptible to migraine headaches. I could always tell when he'd been personally setting c

My father used dynamite in his work (geological exploration). He was susceptible to migraine headaches. I could always tell when he'd been personally setting charges, because he'd come home with a killer headache on those days. Not because of overage 'sweating' dynamite, but because of his high sensitivity to headache triggers like minute amounts of nitroglycerine vapor.