Herb,
My friend Huber Leath of the Strasburg RR (he put together the group that saved the railroad), told me that they used rakes to remove the asbestos/magnesia from boilers because they didn't know any better about getting particles airborne.
I recall the asbestos shop at a military base I worked at. There were six guys that worked in that shop: one developed lung difficulties, the other five asbestosis/cancer and went to the great beyond not from old age. Not good for being in that shop statistically speaking.