I'm a fairly severe asthmatic, so if I'm still alive you have nothing to worry about!
My basement is so dirty I never noticed the fly ash accumulation until reading posts here. I see it on the top of the stove, plumbing, furnace etc. I get a face full of fly ash twice a day when I shake the stove. Most of it lands in the pan, but when I shovel out the sides where the pan doesn't reach, it goes everywhere.
I guess I'm lucky to have nobody living across the street from my house. I have a pile of ashes from a total of 6 tons of coal from the past season and this season! I just wing the pan & let 'em fly!
I used several buckets full to fill a soft spot by my mailbox. The mailman & paper guy were almost getting stuck there before. The ash built it up nice. I'll have to re-do the area once it thaws & gets muddy.
I wish they'd use this stuff instead of salt around here. Then in 5 years we wouldn't have just a seat, frame & engine to drive around!