Arnold Howard on sun 1 aug 99
I lived in Tripoli, Libya as a boy and remember the sand storms. Yet no
one was concerned with the safety hazard of silica. As I understand,
blowing sand storms are not much of a silica safety hazard, because the
particles are large enough to be expelled from the lungs by coughing.
It is the smaller particles that cause harm.
What mesh size of silica sand should be used on kiln shelves--150 -
200?
What types of silica are the worst health hazard?
Thanks,
Arnold Howard
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wschran@erols.com on tue 3 aug 99
<19990730041521.14593.rocketmai-@web804.mail.yahoo.com> wrote:
original article:http://www.egroups.com/group/clayart/?start=49113
> ----------------------------Original message-------------------------
---
> I lived in Tripoli, Libya as a boy and remember the sand storms. Yet
no
> one was concerned with the safety hazard of silica. As I understand,
> blowing sand storms are not much of a silica safety hazard, because
the
> particles are large enough to be expelled from the lungs by coughing.
> It is the smaller particles that cause harm.
>
> What mesh size of silica sand should be used on kiln shelves--150 -
> 200?
>
> What types of silica are the worst health hazard?
>
> Thanks,
>
> Arnold Howard
> _____________________________________________________________
> Do You Yahoo!?
> Free instant messaging and more at http://messenger.yahoo.com
>Arnold - Any powdered silica, in any amount, should be considered
dangerous to inhale. Always wear an OSHA approved respirator with
silica or any material containing silica.
Bill
>
Edouard Bastarache on tue 3 aug 99
------------------
Hello Arnold,
cases of simple silicosis have been described among members of
tribes(Bedouins) living in the Sahara desert due to sand storms.
Micro-nodular lesions are present on chest X-rays.
They do not seem to develop classical silicosis, this simple form of
pneumoconiosis
does not seem to cause clinical symptoms/signs.
( Encyclop=E9die M=E9dico-Chirurgicale,Toxicologie, Pathologie =
Professionelle,
1999)
The crystalline silica, alpha quartz, is the major cause of silicosis
worldwide.
Although the silica polymorphs, cristobalite and tridymite, prove more toxic
for cells and are highly fibrogenic under experimental conditions, these two
mineralogic variants are of more limited health variance.
Quartz particles in the occupational setting range widely in size, but those
less than 1 micron are believed to be the most pathogenic.
Since large particles impact and sediment in the nares and the major
airways,
only relatively small particles enter the acini(lungs)
The size of silica particles retained in the human lung is remarkably
constant,
with median diameters ranging from 0.5 to 0.7 micron.
Silicosis can develop after 5-25 years of occupational exposure to
crystalline
SIO2(quartz, cristobalite and tridymite=3B in this approximately order of
inceasing fibrogenicity)
Later,
Edouard Bastarache
edouardb=40sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/=7Eedouardb/
-----Message d'origine-----
De : Arnold Howard =3Cajhparagon=40yahoo.com=3E
=C0 : CLAYART=40LSV.UKY.EDU =3CCLAYART=40LSV.UKY.EDU=3E
Date : 1 ao=FBt, 1999 11:01
Objet : A question on silica safety
----------------------------Original message----------------------------
I lived in Tripoli, Libya as a boy and remember the sand storms. Yet no
one was concerned with the safety hazard of silica. As I understand,
blowing sand storms are not much of a silica safety hazard, because the
particles are large enough to be expelled from the lungs by coughing.
It is the smaller particles that cause harm.
What mesh size of silica sand should be used on kiln shelves--150 -
200?
What types of silica are the worst health hazard?
Thanks,
Arnold Howard
=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F==
5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5=
F=5F=5F=5F=5F=5F=5F=5F=5F=5F=5F
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