> Nolan Penney wrote:
>
> > Yes. Just like it's ok for you to breath it when you're at the beach
Silicosis is only caused by breathing crystalline silica particles in the
respirable size range, which is less than 0.2 microns. Beach sand does not
contain such particles (not that I'm suggesting you should breathe beach
sand).
> or driving down a dirt road.
Same problem, essentially none of the dangerous particles are in the air
over a dirt road. Breathing the dust from a dirt road is not especially
good for you, but will not cause silicosis.
> It's a matter of concentration. By the time
> > it gets to your neighbor, it's very diluted.
Silicosis is a "cumulative exposure" disease ... every particle that finds
it's way into your lungs will reduce your lung capacity by some amount.
Long term exposure to even tiny amounts can have a severe cumulative effect.
> It is also relatively "heavy" and drops out of the air fairly quickly.
Not true, the particles in question are plenty small enough to be held
suspended for long times, especially if imparted with a static charge as is
typical with sandblasting.
> Unless your neighbors are very close to your exhaust, there shouldn't be
> a problem, especially if the shop vac has a decent bag in it.
No shop vac bag in the world has any hope of stopping a 0.2 micron particle.
Most of them won't stop particles 20 times that size, it's like trying to
catch beach sand with chickenwire. Same thing goes for those felt things
you put over your nose & mouth.
The use of sand for sandblasting was outlawed in the UK in 1950, and the
rest of Europe followed suit in 1966. NIOSH has recommended the same ban in
the US since 1974.
http://www.cdc.gov/elcosh/docs/d0100/d000048/d000048.html
http://www.cdc.gov/niosh/92-102.html
has a story of a worker who died of silicosis in spite of wearing an
approved respirator while sandblasting ...
Randall
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