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Path: utzoo!attcan!uunet!cs.utexas.edu!csd4.milw.wisc.edu!indri!uflorida!novavax!rwright
From: rwright@novavax.UUCP (Ronald K. Wright)
Newsgroups: unix-pc.general,comp.sys.att,sci.electronics,sci.med
Subject: Re: re toner hazards (was Re: Conductive Dust Bunnies)
Message-ID: <1371@novavax.UUCP>
Date: 8 Jul 89 10:21:30 GMT
References: <1989Jun14.042949.597@ivucsb.sba.ca.us> <19512@cup.portal.com> <321@cbnewsi.ATT.COM> <1419@cbnewsc.ATT.COM> <1989Jun28.164955.3005@ziebmef.uucp> <41@oink.UUCP>
Reply-To: rwright@novavax.UUCP (Ronald K. Wright)
Organization: University of Miami, School of Medicine,Ft. Lauderdale..(via Nova U)
Lines: 33

In article <41@oink.UUCP> jep@oink.UUCP (James E. Prior) writes:
>Something that baffles me is why coal dust causes black lung.  It seems 
>that coal dust is also pretty inert.  

Not true.  It is microscopic silica particles, similar to asbestos, which
causes the damage of "black lung".  Coal dust contains silica.  The carbon
is irrelevant except to give the lungs color.

>I've never seen a copier repairer's face blackened like that of a miner's.  

Nor have I seen it in their lungs and I have looked at quite a few of those.
Generally, particles must be 5 microns in maximum cross section or less in size to get into the small air sacs of the lung.  Failing to do that, any particles
which are breathed into the lung are cleaned out rather rapidly by an extremely
efficient process.  From the way peoples lungs look, I would surmise that the
xerographic material is either bigger than 5 micron or some other factor 
prevents the carbon from getting into the lung.

Again if it did it would not itself do anything but make the lungs black.
Black lungs do not make black lung disease.  Anyone growing up in European or
American cities in the 30's through the 50's has black colored lungs because
of the coal burning and carbon realease associatated therewith.  Cigarette
smokers do as well.  It is not the color but the mineral fibers which cause
the disease.

To my knowledge there are no silica particles in xerographic materials and 
thus no danger of black lung disease.

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R. K. Wright MD 			 |  uflorida!novavax!medexam!rkw
Chief Medical Examiner		         |  uflorida!novavax!rwright
Associate Professor Pathology            |  
University of Miami School of Medicine   |  
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