Judy Musicant on wed 16 sep 98
In a recent post, someone mentioned adding manganese to a cream glaze to get
dark specks--prompts me to report on a discussion with Stephen Hill at a
recent workshop. He has been using a beautiful manganese glaze for the past
few years, but plans to stop. He told us about a very well known potter who
is very sick and unable to work (rather not report the name for privacy's
sake) who is quite sure it is the result of manganese poisoning--claims it
is the result of the kiln fumes while the ware is being fired, and not from
handling the manganese during the mixing process. Pretty scary stuff.
Perhaps not worth fooling around with manganese.
Judy Musicant
Chris Schafale on thu 17 sep 98
> ----------------------------Original message----------------------------
> In a recent post, someone mentioned adding manganese to a cream glaze to get
> dark specks--prompts me to report on a discussion with Stephen Hill at a
> recent workshop. He has been using a beautiful manganese glaze for the past
> few years, but plans to stop. He told us about a very well known potter who
> is very sick and unable to work (rather not report the name for privacy's
> sake) who is quite sure it is the result of manganese poisoning--claims it
> is the result of the kiln fumes while the ware is being fired, and not from
> handling the manganese during the mixing process. Pretty scary stuff.
> Perhaps not worth fooling around with manganese.
>
As with all toxicity issues, I think it's worth saying that "it
depends." My understanding about manganese is that the toxicity
problems have been associated with inhalation, through
exposure to fumes as might occur with raku firing, or possibly
through exposure to very fine dust. The kind of granular manganese
that is used to produce speckles in clay or glaze seems unlikely to
be a problem. If anyone has solid evidence to the contrary, please
let me know.
Chris
Light One Candle Pottery
Fuquay-Varina, NC
candle@nuteknet.com
Richard Aerni on thu 17 sep 98
Judy,
I think, rather than doing away with our usage of manganese and other
substances which can be toxic, it is better to educate ourselves as to
their hazards and how they can be handled safely, if possible. To that
end, I think that clayart has been performing a service to the potting
community for some time now. The postings of Monona Rossol, Ron Roy, Tom
Buck, and others, have been extremely helpful in sharing their knowledge
of these areas. But, I also think that we can go too far by just saying
"this is toxic, keep away from it at all costs". Much better to know in
what situations it is toxic, and wherein the dangers lie. I was given a
good amount of clay and glaze material by a local college, because the
campus enviromental guy, a friend, decided to go through the ceramic
studios and check out all the MSDSs and get rid of anything "toxic", or
hazardous. So, I got silica, ball clays, kaolin, talc, etc, since they
were all marked as hazardous.
In Steven's case, I also think that clayart helped to educate him as to
the hazards of manganese use. When all of those postings about his
manganese use went on clayart last spring (?), I printed them out. I had
a long talk with him this summer, recapping all of the posts and
recommendations from our clayart experts. As his home studio is not
particularly well ventilated, and the kiln is just feet from his throwing
/forming area, I expressed some concern that he might be inhaling the
volatolized manganese from the firings (thanks to Dannon Rhudy for
sharing her thoughts on the matter with me earlier in the spring). At
any rate, Steven was aware of the hazards of manganese from a handling
standpoint, but not aware of the hazards of inhalation of the fumes from
the kiln. I'm glad that he took the time to check into it and inform
himself.
I don't mean to digress here. My point is not that I know Steven, but
rather that one must get to know one's materials. What they can and
can't be used for, and with. Educate yourself. Read. Research. Think.
Don't merely say, "someone said this is bad, don't use it", but find out
why, and in what circumstances.
OK. Off the soapbox.
Richard Aerni
Bloomfield, NY
Judy Musicant wrote:
>
> ----------------------------Original message----------------------------
> In a recent post, someone mentioned adding manganese to a cream glaze to get
> dark specks--prompts me to report on a discussion with Stephen Hill at a
> recent workshop. He has been using a beautiful manganese glaze for the past
> few years, but plans to stop. He told us about a very well known potter who
> is very sick and unable to work (rather not report the name for privacy's
> sake) who is quite sure it is the result of manganese poisoning--claims it
> is the result of the kiln fumes while the ware is being fired, and not from
> handling the manganese during the mixing process. Pretty scary stuff.
> Perhaps not worth fooling around with manganese.
>
> Judy Musicant
Edouard Bastarache on fri 18 sep 98
Hello Richard,
congratulations.
Very good and interesting message on manganese.
Lots of chemicals tagged "toxic" may be use safely;
even lead, if the proper info. is given to workers as to
health effects,safe ways to use them, protective measures
to implement and medico-environmental surveillance etc..
Later,
Edouard Bastarache M.D.(Occupational & Environmental Medicine)
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
----------
> De : Richard Aerni
> A : CLAYART@LSV.UKY.EDU
> Objet : Re: Manganese dangers
> Date : 17 septembre, 1998 09:28
>
> ----------------------------Original message----------------------------
> Judy,
>
> I think, rather than doing away with our usage of manganese and other
> substances which can be toxic, it is better to educate ourselves as to
> their hazards and how they can be handled safely, if possible. To that
> end, I think that clayart has been performing a service to the potting
> community for some time now. The postings of Monona Rossol, Ron Roy, Tom
> Buck, and others, have been extremely helpful in sharing their knowledge
> of these areas. But, I also think that we can go too far by just saying
> "this is toxic, keep away from it at all costs". Much better to know in
> what situations it is toxic, and wherein the dangers lie. I was given a
> good amount of clay and glaze material by a local college, because the
> campus enviromental guy, a friend, decided to go through the ceramic
> studios and check out all the MSDSs and get rid of anything "toxic", or
> hazardous. So, I got silica, ball clays, kaolin, talc, etc, since they
> were all marked as hazardous.
>
> In Steven's case, I also think that clayart helped to educate him as to
> the hazards of manganese use. When all of those postings about his
> manganese use went on clayart last spring (?), I printed them out. I had
> a long talk with him this summer, recapping all of the posts and
> recommendations from our clayart experts. As his home studio is not
> particularly well ventilated, and the kiln is just feet from his throwing
> /forming area, I expressed some concern that he might be inhaling the
> volatolized manganese from the firings (thanks to Dannon Rhudy for
> sharing her thoughts on the matter with me earlier in the spring). At
> any rate, Steven was aware of the hazards of manganese from a handling
> standpoint, but not aware of the hazards of inhalation of the fumes from
> the kiln. I'm glad that he took the time to check into it and inform
> himself.
>
> I don't mean to digress here. My point is not that I know Steven, but
> rather that one must get to know one's materials. What they can and
> can't be used for, and with. Educate yourself. Read. Research. Think.
> Don't merely say, "someone said this is bad, don't use it", but find out
> why, and in what circumstances.
>
> OK. Off the soapbox.
>
> Richard Aerni
> Bloomfield, NY
>
>
>
>
> Judy Musicant wrote:
> >
> > ----------------------------Original
message----------------------------
> > In a recent post, someone mentioned adding manganese to a cream glaze
to get
> > dark specks--prompts me to report on a discussion with Stephen Hill at
a
> > recent workshop. He has been using a beautiful manganese glaze for the
past
> > few years, but plans to stop. He told us about a very well known
potter who
> > is very sick and unable to work (rather not report the name for
privacy's
> > sake) who is quite sure it is the result of manganese poisoning--claims
it
> > is the result of the kiln fumes while the ware is being fired, and not
from
> > handling the manganese during the mixing process. Pretty scary stuff.
> > Perhaps not worth fooling around with manganese.
> >
> > Judy Musicant
Kathi LeSueur on sat 19 sep 98
In a message dated 9/17/98 1:31:03 PM, you wrote:
>I think, rather than doing away with our usage of manganese and other
>substances which can be toxic, it is better to educate ourselves as to
>their hazards and how they can be handled safely, if possible.>>
>In Steven's case,............. As his home studio is not
>particularly well ventilated, and the kiln is just feet from his throwing
>/forming area, I expressed some concern that he might be inhaling the
>volatolized manganese from the firings>>
For the past 5 years I've used a glaze with a high manganese content. It is
one of my most popular glazes comprising over 50% of my production. A year and
a half ago I lost my sense of smell. My doctor's first thought was toxic
poisoning from glaze ingredients. After a battery of tests (including
extensive heavy metals testing) it was found that I did not have any kind of
poisoning from glaze materials. I was essentially very healthy. This was very
reassuring after 22 years as a full-time potter.
I don't dispute that manganese is toxic and can cause problems but, as Richard
points out, ventilation is extremely important. Respirators, latex gloves ( I
know I hate them, too), and a good ventilation system go a long way in
reducing the dangers.
Kathi LeSueur
Ron Roy on sun 20 sep 98
There are different degrees of toxicity and different delivery systems -
and I don't think we know the whole story yet. It is not so easy to educate
oneself - the kind of information we are talking about here is absent from
most books on pottery - in fact most don't even mention many of the
dangers.
I wish it was possible for potters to know if their glazes are safe - but I
am appalled at the lack of concern of some individuals who post glazes and
advice here on clay art. I even see lead glazes posted.
What if you are not exactly sure about some of the issues but you do have
reservations? What is the right thing to do when you see the scull and
crossbones on the bag or when you see a potter disabled because they did
not even know what to avoid.
I do say "there are concerns" from time to time. I feel it is important for
potters to be aware - not only of the problems that can affect them but
also their customers. I seem to think that some awareness will lead to
better education and we will all be better off because of it.
I also agree with Richard that just giving the bad news is not enough - but
in the mean time - while we are getting educated - I don't want anyone to
feel it is wrong to voice their concerns here - ClayArt is an excellent
forum for sorting these things out. What I am saying is - it is better for
those who are misinformed to post their thoughts - so that we all will
become better educated through the process of discussion and evaluation.
>What they can and
> can't be used for, and with. Educate yourself. Read. Research. Think.
> Don't merely say, "someone said this is bad, don't use it", but find out
> why, and in what circumstances.
Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849
Web page: http://digitalfire.com/education/people/ronroy.htm
Ron Roy on tue 22 sep 98
There are different degrees of toxicity and different delivery systems -
and I don't think we know the whole story yet. It is not so easy to educate
oneself - the kind of information we are talking about here is absent from
most books on pottery - in fact most don't even mention many of the
dangers.
I wish it was possible for potters to know if their glazes are safe - but I
am appalled at the lack of concern of some individuals who post glazes and
advice here on clay art. I even see lead glazes posted.
What if you are not exactly sure about some of the issues but you do have
reservations? What is the right thing to do when you see the scull and
crossbones on the bag or when you see a potter disabled because they did
not even know what to avoid.
I do say "there are concerns" from time to time. I feel it is important for
potters to be aware - not only of the problems that can affect them but
also their customers. I seem to think that some awareness will lead to
better education and we will all be better off because of it.
I also agree with Richard that just giving the bad news is not enough - but
in the mean time - while we are getting educated - I don't want anyone to
feel it is wrong to voice their concerns here - ClayArt is an excellent
forum for sorting these things out. What I am saying is - it is better for
those who are misinformed to post their thoughts - so that we all will
become better educated through the process of discussion and evaluation.
>What they can and
> can't be used for, and with. Educate yourself. Read. Research. Think.
> Don't merely say, "someone said this is bad, don't use it", but find out
> why, and in what circumstances.
Ron Roy
93 Pegasus Trail
Scarborough, Ontario
Canada M1G 3N8
Tel: 416-439-2621
Fax: 416-438-7849
Web page: http://digitalfire.com/education/people/ronroy.htm
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