Monona Rossol on tue 24 dec 96
Anne M. Bracker wrote:
----------------------------Original message----------------------------
> I pulled the
> MSDS (Material Safety Data Sheet) on manganese, and here is what I found
> (applicable excerpts only - not the whole MSDS), if anyone is still
> interested. MSDS are available from your supplier. By posting this
> material, I do not mean to alarm anyone, but just to inform. <
There's a very old Good Book that says: fear is the beginning of wisdom.
I'd like to comment on some of the MSDS information. MSDSs are wonderful to
have, but they vary greatly in accuracy, and many are downright misleading.
> Nowhere on the MSDSs that I have found for Manganese did it say that it
> can be absorbed by the skin. <
I know of no studies of manganese skin absorption. The US National
Toxicology Program said in 1993 that they couldn't find any such
studies either. We used to think that the metallic compounds in general
didn't skin-absorb. Then the Australian Government financed a study of lead
metal dust, lead oxide and lead nitrate. Right through the skin they all
went like it wasn't there. Now we don't know what to think.
> **From Foote Mineral Company MSDS for Manganese Dioxide, revision date
> 7/25/85** <
This revision date is not acceptable. Canada has a wonderful law that makes
a three-year-old MSDSs automatically invalid. All countries should have a
similar law.
> Exposure Limit Value: OSHA limits exposure to manganese to 5mg/m(cubed)<
This OSHA Permissible Exposure Limit (PEL) is not the ordinary
eight-hour-time weighted average value, it is a **ceiling** limit which is
never to be exceeded. This section should also list the TLV-TWA which is 0.2
mg/m3 which gives you a better idea of how every toxic this material is.
> Primary Route of exposure: Inhalation <
> Signs and Symptoms of Overexposure: Sleepiness, muscular weakness or
> tremors are the first signs of overexposure. If such symptoms occur,
> remove person from exposure and seek medical attention.
> Effects of overexposure: Manganese dioxide is a toxic chemical. It is
> reported in animal tests that manganese dioxide can be fatal in a single
> dose of as low as 49mg/kg body weight inhaled for seven hours
> --equivalent to 3300mg for the average person. Manganese fumes and dust
> may affect the central nervous system. Chronic poisoning symptoms
> include sleepiness, muscular weakness and twitchings or tremors similar
> to Parkinson's Syndrome. <
Important information. What would be even more useful to say is that at
the very low doses allowed at the PEL-Ceiling and the TLV-TWA, there are
studies showing small but permanent changes in workers' coordination and
brain function which are consistent with early Parkinson's disease.
> Carcinogenicity: Manganese ore is not listed as a carcinogen or
> potential carcinogen by the National Toxicology Program of the US Public
> Health Service, nor has it been found to be a carcinogen or potential
> carcinogen by OSHA or the International Agency for Research on Cancer.
> Foote is not aware of any data indicating that manganese ore produces
> cancer. <
This is a good example of how misleading MSDSs can be. In 1985 when this was
written, manganese had NEVER been studied by ANY of those agencies for its
ability to cause cancer! However, in 1992, there was one National Toxicology
Program study of a single manganese compound, manganese sulfate, which
indicated it was not a carcinogen. Still, to this day, manganese has never
been formally evaluated by NTP or any of the agencies listed in the MSDS.
---------------------------------------------
> **From American Minerals MSDS for Manganese Dioxide, revision date
> 12/13/95** <
That's more like it.
> Effects of Exposure: Excessive inhalation of fumes from many metals can
> produce metal fume fever. Symptoms consist of chills and fever and come
> on a few hours after large exposures. <
> Effects of Chronic Exposure: Excessive and prolonged inhalation of
> manganese (generally over 2 years exposure) can cause damage to the
> central nervous system. Specifically, the pathology resembles
> Parkinson's Disease. Also, workers exposed to high concentrations of
> manganese dust show an unusually high incidence of respiratory disease.
> Chronic exposure to iron, alumina, and silica may also cause pulmonary
> disorders. <
--------------------------
> **From Chemetals Incorporated MSDS for Manganese Carbonate, issue date
> 11/95** >
> Acute Health Hazards: Exposure to high concentrations of manganese fumes
> may cause metal fume fever. <
> Chronic Health Hazards: Exposure to heavy concentrations of manganese
> dust or fumes for as little as three months may produce chronic
> manganese poisoning, but usually cases develop after 1-3 years exposure.<
> Acute symptoms of Exposure: Metal fume fever - chills, fever, muscle
> aches, headaches, dry throat. <
> Chronic symptoms of Exposure: Sleepiness, weakness in legs, muscular
> twitchings, nocturnal leg cramps, slowness of speech, languor. <
Pretty good description--and these changes can be permanent. Not a lot of
fun.
-------------------------
MSDSs: read 'em with skepticism--and verify the information.
Monona Rossol, industrial hygienist
Arts, Crafts and Theater Safety
181 Thompson St., # 23
New York, NY 10012-2586
Dannon Rhudy on thu 26 dec 96
----------------------------Original message----------------------------
Monona,
Thanks. All my early information re: manganese was from my first
ceramics instructor. In general he was not particularly cautious,
but where manganese was concerned, he was exceedingly
careful, warned the class, didn't let it be used unless careful
instruction had been given regarding skin absorption, dangers of
breathing, etc. And why? A friend of his had died of manganese
poisoning. Some lessons are real easy to learn...
Thanks particularly for pointing out that reports stating that "no
evidence has shown that substance X is dangerous" does not
mean that it is safe. It may only mean it's never been tested.
Dannon Rhudy
potter@koyote.com
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