Anne on sun 22 dec 96
Okay, I know I am responding a little late to this particular thread,
but everyone knows how hectic holidays can be! :) Anyway, the comments
on manganese got me thinking, and I did a little research. 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. Nowhere on
the MSDS that I have found for Manganese did it say that it can be
absorbed by the skin. The main route of exposure is by inhalation.
Wear your respirators!
Otherwise, have a safe and healthy holiday season!
Anne M. Bracker
**From Foote Mineral Company MSDS for Manganese Dioxide, revision date
Exposure Limit Value: OSHA limits exposrue to manganese to 5mg/m(cubed)
Primary Route of exposure: Inhalation
Signs and Symptoms of Overexposure: Sleepiness, muscular weakness or
tremors are the first signs of overexposure. If such sypmtoms 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 Synrome.
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
**From American Minerals MSDS for Manganese Dioxide, revision date
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
**From Chemetals Incorporated MSDS for Manganese Carbonate, issue date
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.
Kong Sang Hui on tue 11 feb 97
How do you do?
My name is Sang Hui Kong. Nice to meet you!
I am an corperate industrial hygienist in Korea.These days I am
wandering the sea of internet for more information about manganism,
because some workers of my corperate appeared to take symtoms of
manganism and Parkison's disease.
It is fortunate that I found your letters about manganese toxicity in
the internet.Among your letter in 1996/12/24 ,you said " at the very low
doses allowed at the PEL and the TLV-TWA, there are STUDIES showing
small but permanent changes in worker's coordination and brain
I want to know about 'STUDIES'.
Could you make me know what 'STUDIES' is and how I can approach them.
I look forward to seeing your reply in my mail-box.
Hope your nice day!
Kris Baum on sun 1 jun 97
Sorry to revive such an old thread, but I was able to get some
information from a nutritionist about manganese that may be of interest
to those of us concerned about it leaching from our glazes.
The National Academy of Sciences, National Research Council (not
a federal govt. agency but an independent agency that does work for the
govt. under contract) is responsible for setting the Recommended Dietary
Allowances (RDAs). I believe that the latest report was done quite a
while ago (maybe 10 years?) and that an update of the RDAs is due in the
next couple of years.
The text of the NRC's report makes some of the following points:
There is no tendency for an increase or decrease in accumulation
of manganese through most of the human life cycle. This is thought to be
a result of adequate dietary intake coupled with strong homeostatic
control (for those non-biologists, this means that the body somehow
manages to keep a balanced level. In pregnancy, the body increases
absorption; if overconsumed, it is probably excreted through the stool.)
In humans, the only manganese toxicity has been observed with
high concentrations of manganese dust or fumes in the air. Dietary
intake of as high as 9 mg/day has shown no toxicity. "In view of the
remarkably steady tissue concentrations of manganese in the U.S.
population and the low toxicity of dietary manganese, an occasional
intake of 10 mg/day by adults can be considered safe. To include an
extra margin of safety, however, the subcommittee recommends a range of
manganese intake from 2 to 5 mg/day for adults."
In animals, the toxicity of ingested manganese doesn't appear
until about 1000ug/g of diet are fed. As in humans, the dust is much
more toxic, resulting in adverse effects on the central nervous system.
IMHO, I'll be sure to wear a mask when weighing the stuff out,
but I'm not going to obsess about the leaching.
Kris Baum, Shubunkin Pottery,
Linda - Pacifica on mon 18 sep 06
I may have posted this before, but it came up this weekend in Ron Roy's glaze calculation workshop, so I thought I'd repeat it.
The following article:
outlines an apparent treatment for manganese toxicity seen in industrial workers with extreme exposure to the metal.
BTW, I got lots of help with my questions about making lower firing glazes out of high fire ones. I recommend Ron's workshops and one or both of the softwares: Glaze Master and Insight. I know that I'll use both of them. AND I've got to get that Hamer and Hamer out and USE it! Son-of-a-gun; no free lunch.