Monona Rossol on mon 26 may 97
---------- Forwarded message ----------
Date: Fri, 2 May 1997 07:19:04 EDT
From: Jeff Lawrence
Subject: Re: fiber v. brick update
----------------------------Original message----------------------------
> To anyone interested in this thread, I discovered a very enlightening and
> candid discussion of refractory ceramic fiber by Marc Ward in the current
> issue of Claytimes. Recommended. < SNIP
Sorry I've been so busy. I feel guilty that I haven't rebutted some of what
was said in this article sooner. The worst error Marc Ward makes is when he
says:
"The danger from RCF is from the free silica."
Dead flat out wrong. The major danger is from the fiber itself. OSHA
proposed a 1 fiber/cc limit for RCF which is only a factor of 10 different
from the asbestos standard of 0.1 fiber/cc. In addition, the RCF Coalition
of manufacturers *agreed* to support and recommend this 1 fiber/cc limit.
The manufacturers themselves also recommend that air sampling and all the
other respiratory protection, protective clothing, hygiene and clean-up
measures consistent with this standard be used.
Granted an estimated 20 percent of the material converts to cristobalite
after firing and this form of silica also is highly toxic and capable of
causing lung fibrosis and cancer. But all this does is give users two
problems instead of one.
Marc also says:
"Other long-term studies of factory workers in the RCF industry have not
shown a link between cancers and exposure."
That's because human studies of workers exposed to RCF are still underway.
One early finding reported is the presence of pleural plaque--the thickening
of the area around the lungs which is associated with asbestos exposure--that
have appeared in 3.1 percent of all the current RCF workers studied and in
12.5 percent of the workers who were first exposed to RCF more than 20 years
ago. What everyone is waiting to see is if the marker fatal asbestos cancer,
mesothelioma, will be seen over the next 20 years in these workers. The
latency period for mesothelioma is 20-40 years after exposure.
Mesothelioma and other cancers are seen in RCF animal tests. EPA says "A
major animal inhalation study ... has shown a positive tumorigenic response
in rats and hamsters, with 35 percent of the hamsters exposed ... developing
pleural mesothelioma and 13 percent of the rats exposed to kaolin RCFs
developing adenoma-carcinomas." (58 FR 28517, May 14, 1993)
Marc also says:
"Brick dust poses the same danger...as does sweeping the studio floor, making
glazes, and making clay. So does driving down a gravel driveway with the
windows open. All these things expose us to free silica and silicates."
Again, the silica is one hazard, the fibers are another. If Marc Ward wants
to be one of the lab rats for the next 40 years, he can be my guest. But he
shouldn't mislead others into thinking driving down a gravel driveway
is in the same league with loading and unloading fiber kilns or raising and
lowering fiber raku kilns when you can see the little fibers floating in the
air and glistening in the sun. It is not.
What I am going to do is make copies of the Clay Times article and send it to
the RCF coalition, Unifrax, and to EPA. Maybe we can get the RCF Coalition
or individual manufacturers themselves to correct some of the information in
this article. After all, they promised EPA under their Stewardship agreement
to provide proper advice to downstream users of their product.
But you can get this advice already by writing the RCF Coalition or Unifrax
Corporation, 2351 Whirlpool St., Niagara Falls NY 14305-2413 and asking for
information about obtaining:
* Working Safely with RCF Products
* Product Stewardship Program for RCF
* A guide to Respiratory Protection
* Complete Health Information and Video
Even these manufacturers publications will do a better job at explaining the
problem than a potter/kiln burner supplier who has a financial interest in
having customers use RCF without all the manufacturer's recommended
precautions.
Monona Rossol, industrial hygienist
Arts, Crafts and Theater Safety
181 Thompson St., # 23
New York, NY 10012-2586 212/777-0062
http://www.caseweb.com/acts/
Monona Rossol on sat 31 may 97
Jeff used an interesting word twice in different forms:
> I would have more faith in Ms. Rossol's observations were > they a bit more
perspicuous.<
> I sincerely wish that she would augment that depth of knowledge with a like >
perspicuity .... <
Perspicuous: Having the quality of perspicuity; clear; lucid.
Perspicuity: Clearness of expression or style; lucidity
Do you really think I'm not being clear about what I'm saying? Are your in any
doubt about my meaning? Bet not.
Monona Rossol
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