Ron Roy on sat 17 may 97
>
>Tri-valent chrome -- Cr2O3 -- it extremely stable material. Anyone who's
>tried to melt it into a glaze knows that. Although you may notice that
>the glaze is kind of yellowish -- that is owing to a bit of hexavalent
>chrome.
>
>
>If you read an MSDS on the material you'd think you're handling death
>itself. Yet here, as with Barium and
>
>KPP --
First of all we are all unique in our genetic make up. Offering the example
of one man surviving exposure to chrome is not exactly a scientific study.
There are those among us who will be affected by exposure to chrome. When
we know how to tell who will be and who won't - then we will be able to
make an inteligent choice.
For those who think chrome is a stable material - try this little
experiment. Put a small amount in your kiln - any source of chrome will do
just fine. Just make a small container of clay - enough to hold a few
grams. Place this in your kiln - say the middle. Now take a clear or white
glaze and add some tin - lets say 5% to get a dramatic effect. Dip some
test tiles in this glaze and place them in different parts of your kiln
with one close to the chrome source - fire at any temperature your glaze
works at.
You will see that chrome becomes volatile and will travel from the source
throughout the kiln. Whenever it touched the tin glaze you will see a
discoloration - usually pink.
Needles to say hanging around that kiln and breathing those fumes is your
choice - I'll pass thanks.
Ron Roy
Toronto, Canada
Evenings, call 416 439 2621
Fax, 416 438 7849
ronroy@astral.magic.ca
Eileen M Streeter on wed 29 oct 97
a query to the safety of the studio environment...
recently we had a visit from the environmental people on campus... and
they let us know that we could no longer use any glaze or engobe
containing chrome... we have to isolate and dispose of any that is
made up as 'hazardous waste' and nothing can go down the drain... due to
it's heavy metal mature... and the fact that our drinking water comes
from the local river... and the filtering system cannot eliminate heavy
metals...
are there any other things we should be aware of? we have been using
chrome since i have been here... green is a favorite color amongst the
students... we have been using and washing it down the drain up to
now... and some wonder what isn't safe in glazed pieces with reaction
to some foods... or the environment...
and why did it take these people so long to inform us... do things get
added to lists randomly over time... suddenly not safe...
are there guide lines established for ceramics safety... if so... and
where do we find them
we assume that if it can be sold... it would have warnings if there is
any danger associated with use... right?
oh well...
eileen
Rick Sherman on thu 30 oct 97
---------------------------original message-------------------------
recently we had a visit from the environmental people on campus...
and they let us know that we could no longer use any glaze or engobe
containing chrome...
eileen
------------------------question---------------------------------------
Eileen: Where are you located? Have all schools in your state had the
same experience? Is it just your location near a water source that is
causing this action?
RS
San Jose, CA
Bonnie Staffel on tue 14 mar 00
Mar. 14, 2000
Dear Clayarters,
A potter friend of mine dips her pots in a chrome glaze with her bare
hands. Is there an absorption problem through her skin through this
practice? I also believe there is some copper in this particular glaze
also. An answer would be greatly appreciated.
Bonnie Staffel - where the early daylight brings the hint of spring in
the air. New birds are appearing on their way north.
Edouard Bastarache on wed 15 mar 00
------------------
Hello Bonnie =26 other potters,
Chromium for Potters
Chromium can have a valence of 2, 3, and 6. Chromium compounds vary greatly
in their toxic and carcinogenic effects. For this reason ACGIH divides
chromium and its inorganic compounds in a number of groupings.
Group =233 is =AB Trivalent chromium compounds =BB
(Cr3+)(chromic compounds) :including chromic oxide (Cr2o3) which is green
chromic oxide, chromic sulfate, chromic chloride, chromic potassium sulfate,
and chromite
ore.
Green chromic oxide is the one i use and i think it is the same for all of
potters=3B the nastiest being hexavalent chromium in group =234, i do not =
think
governement officials would let us use the latter.
So what applies is the toxicology of trivalent compounds.
Routes of Absorption : Chromic salts are minimally absorbed following
inhalation.Trivalent chromium salts are generally poorly absorbed through
intact skin, once the dermal barrier is broken, however, absorption may
occur. Trivalent chromium salts are absorbed following ingestion, but only
1-25=25 of the dose ingested is absorbed.
Toxicity :
There is little evidence of significant toxicity from chromic salts,
probably because of poor penetration of skin and mucous membranes.Dermatitis
from chromic salts has been reported.
The lungs of some workers exposed to chromite dust have been shown to be the
seat of
pneumoconiotic changes consisting of slight thickening of interstitial
tissue and alveolar septa, with histological fibrosis and hyalinisation.
A refractory plant using chromite ore to make chromite brick had no excess
of lung cancer deaths over a 14-year period.
Inhalation of trivalent chromium salts can cause occupational asthma.
The IARC(International Agency for Research on Cancer, Lyon ,France) has
determined that there is inadequate evidence in humans and animals for the
carcinogenicity of metallic chromium and trivalent chromium compounds(III).
Trivalent compounds, do not appear to cause other effects associated with
the hexavalent chromium compounds, such as chrome ulcers (hands and
forearms), irritative dermatitis, nasal septal perforation, lung cancer,
etc.
References :
1-Chemical Hazards of the Workplace, Proctor =26 Hughes.
2-Dangerous Properties of Industrial Materials, Sax =26 Lewis.
3-Hazardous Materials Toxicology, Sullivan =26 Krieger.
COPPER =26 COMPOUNDS
Copper is a metal used as an alloy in brass and bronze, as a component in
some solders, in pigments such as emerald green, in ceramic glazes, and as
a salt in the lithographic process.
Copper is an essential metal and the daily requirement has been estimated
at 30 micrograms/kg of body weight for an adult.
The normal concentration of copper in blood plasma is 1 mg/liter.
The gastrointestinal absorption of soluble copper is regulated by the need
and is usually around 50=25=3B uptake may also take place after inhalation.
Elimination of copper is slow and takes place via bile.
The chronic accumulation of copper in the body is rare and occurs in
Wilson's disease caused by an inborn error of the copper metabolism
characterized by a diminished capacity to eliminate copper via bile.This
leads to secondary lesions in the liver and the brain.
The salts are irritants to the skin, eyes,and mucous membranes. Ingestion of
copper salts may cause vomiting, diarrhea, hemorragic gastritis, and
excessive salivation.
Copper sulfate has clinically (medicine) been used as an emetic. Vineyard
sprayers using a solution containing aqeuous copper sulfate developed
granulomatous and fibrotic lung lesions.Liver granulomatas containing copper
have also been found in vineyard sprayers.Clinical liver disease is usually
not significant, but liver granulomas occasionally result in hepatomegaly,
necrosis and fibrosis.
Experimental studies in mice support that copper is an etiologic(cause) for
lung fibrosis.
Inhalation of copper dust and fume results in irritation of the respiratory
tract, ulceration and perforation of nasal septum, metallic or sweet taste,
and in some instances, discoloration of the skin and hair.The inhalation of
metal fumes produced at high temperature, such as welding, may cause =
=22metal
fume fever=22, an influenza-like(benign) illness.
Copper sulfate is also used in the whitewashing and leather
industry.Toxicity is primarily due to accidental and suicidal attempts, and
results in intravascular hemolysis, methemogloninemia, renal failure and
often death.
Remember clinical liver disease due to copper is not usually significant.
High copper content in drinking water and food may contribute to the
development of severe liver damage in infants.
Copper compounds used by potters are not considered hazardous as well as
for pottery users.Copper in glazes fluxed by lead compounds will leach more
lead.
Good studio housekeeping is always good practice. Avoidance of processes
generating unnecessary dust is also important and the wearing of an approved
dust mask when the exposure seems hazardous is also good practice.
REFERENCES :
1-Occupational Medicine,Carl Zenz, last edition.
2-Occupational =26 Environmental Medicine,Joseph Ladoue, last edition.
3-Hazardous Materials Toxicology, Sullivan =26 Krieger=3B last edition.
Hazardous Materials Used in Arts and Crafts,chapter 60,
Edouard Bastarache
Dans / In =22La Belle Province=22
edouardb=40sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/=7Eedouardb/
-----Message d'origine-----
De : Bonnie Staffel =3Cbstaffel=40torchlake.com=3E
=C0 : CLAYART=40LSV.UKY.EDU =3CCLAYART=40LSV.UKY.EDU=3E
Date : 14 mars, 2000 14:11
Objet : Chrome
=3E----------------------------Original message----------------------------
=3EMar. 14, 2000
=3E
=3EDear Clayarters,
=3E
=3EA potter friend of mine dips her pots in a chrome glaze with her bare
=3Ehands. Is there an absorption problem through her skin through this
=3Epractice? I also believe there is some copper in this particular glaze
=3Ealso. An answer would be greatly appreciated.
=3E
=3EBonnie Staffel - where the early daylight brings the hint of spring in
=3Ethe air. New birds are appearing on their way north.
Dannon Rhudy on wed 15 mar 00
......>A potter friend of mine dips her pots in a chrome glaze with her bare
>hands. Is there an absorption problem through her skin through this
>practice? .....
There's always the possibility of absorption, and chrome is not
very tasty stuff. I doubt if it is necessary to be hysterical
about it, but - nothing wrong with a) tongs, and b) rubber gloves.
I wear gloves to glaze, usually, though I occasionally don't bother.
But for all-day glaze sessions I do. It is more a matter of comfort
in my case - glazes seem much harder on skin than clay/throwing, in
my experience. And tongs do less to disturb the surface than my fingers.
regards
Dannon Rhudy
potter@koyote.com
Eileen Streeter on thu 16 mar 00
edouard...
what occurs if chromium or copper is released into the general or even local
drinking water sources... we have many gound wells and not so
technologically advanced water purity systems here in nh.... ?? any
suggestions in dealing with disposal... ?
thanks...
eileens
Edouard Bastarache on fri 17 mar 00
------------------
Hello Eileen,
There are a few factors to consider :
1- The amounts of these chemicals used over a given period of time.
2- These are mainly either in glaze pails or on your pots.
3- The sizes of underground sheets of water.
4- Rate of renewal of these sheets.
5- Number of studio potters in your area.
6- Specific toxicology of these chemicals :
A-Copper compounds are not very toxic.
B-Trivalent chromium salts are absorbed following
ingestion, but only 1-25=25 of the dose ingested is absorbed
The extent of absorption varies with the particular salt
ingested and circumstances of ingestion.
There is little evidence of significant toxicity from chromic
salts, probably because of poor penetration of mucous membranes.
Mucous membranes line our gastro-intestinal system.
Green chromium oxide is trivalent.
So I dont think your situation is problematic.
Later,
Edouard Bastarache
Dans / In =22La Belle Province=22
edouardb=40sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/=7Eedouardb/
-----Message d'origine-----
De : Eileen Streeter =3CPigdog19=40aol.com=3E
=C0 : CLAYART=40LSV.UKY.EDU =3CCLAYART=40LSV.UKY.EDU=3E
Date : 16 mars, 2000 13:37
Objet : Re: Chrome
=3E----------------------------Original message----------------------------
=3Eedouard...
=3E
=3Ewhat occurs if chromium or copper is released into the general or even
local
=3Edrinking water sources... we have many gound wells and not so
=3Etechnologically advanced water purity systems here in nh.... ??
any
=3Esuggestions in dealing with disposal... ?
=3E
=3Ethanks...
=3Eeileens
Lesley Alexander on mon 16 dec 02
From reading Mr. Bastarche's (is that spelled right?) discussion of
chromium I gather that the plain green chromium (Laguna's catalogue
lists it as Chrome Oxide-Green, Cr2O3) has the hexavalent form that can
be absorbed thru the skin and can cause cancer etc. Bad news. Green
stains, however, are spinels that cannot be absorbed thru the skin. Just
don't breathe the stuff. I'd opt for the stains or, if not using much,
wear gloves.... As for Iron Chromate and Potassium Dichromate, why is
it necessary to bother with the stuff? It was pretty technical, have I
got it right? Lesley
Edouard Bastarache on mon 16 dec 02
Well Lesley,
sorry, you did not read it right.
Green chromium oxide is trivalent and only penetrates
with much difficulty into the skin.
For more information go to
http://perso.wanadoo.fr/smart2000/chrome_chromium.htm
or
http://digitalfire.com/education/toxicity/materialsafety.html
You also mispelled my name (Hehehehehe); do not worry
I am used to it.
Later,
"Ils sont fous ces Quebecois"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
http://sorel-tracy.qc.ca/~edouardb/
http://perso.wanadoo.fr/smart2000/index.htm
Rebecca P on tue 17 dec 02
>You also mispelled my name (Hehehehehe); do not worry
>I am used to it.
Hi Edouard,
Don't feel like the Lone Ranger! (That really goes back - giving away my
age!) People are always trying to make Pierre into Pierce.
Rebecca (guess)
Oak Island, NC
_________________________________________________________________
Protect your PC - get McAfee.com VirusScan Online
http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
Edouard Bastarache on tue 17 dec 02
Hehehehehe,
I remember practicing English by reading Lone Ranger's
comic strips in the 50s.
I also read MAD!!!
Later,
"Ils sont fous ces Quebecois"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
http://sorel-tracy.qc.ca/~edouardb/
http://perso.wanadoo.fr/smart2000/index.htm
----- Original Message -----
From: Rebecca P
To:
Sent: Tuesday, December 17, 2002 8:35 AM
Subject: Re: Chrome
> >You also mispelled my name (Hehehehehe); do not worry
> >I am used to it.
>
> Hi Edouard,
>
> Don't feel like the Lone Ranger! (That really goes back - giving away my
> age!) People are always trying to make Pierre into Pierce.
>
> Rebecca (guess)
> Oak Island, NC
>
> _________________________________________________________________
> Protect your PC - get McAfee.com VirusScan Online
> http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
culling on thu 26 dec 02
If chrome is so bad why do some green eyeshadows list it as an
ingredient!!!?- definitely an argument to avoid the stuff!
Steph
----- Original Message -----
From: "Lesley Alexander"
To:
Sent: Tuesday, December 17, 2002 8:37 AM
Subject: Chrome
> >From reading Mr. Bastarche's (is that spelled right?) discussion of
> chromium I gather that the plain green chromium (Laguna's catalogue
> lists it as Chrome Oxide-Green, Cr2O3) has the hexavalent form that can
> be absorbed thru the skin and can cause cancer etc. Bad news. Green
> stains, however, are spinels that cannot be absorbed thru the skin. Just
> don't breathe the stuff. I'd opt for the stains or, if not using much,
> wear gloves.... As for Iron Chromate and Potassium Dichromate, why is
> it necessary to bother with the stuff? It was pretty technical, have I
> got it right? Lesley
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
melpots@pclink.com.
>
iandol on fri 27 dec 02
Dear Steph Culling,
Green Chromium Oxide, Cr2O3 is insoluble in water and only slightly =
soluble in acids and alkali solutions
Red Chromium Oxide, CrO3 is red crystaline material which is highly =
soluble in water. It is this material I have always understood to be the =
cause for concern.
Many years ago I had dealings with Engineers at Associated Chrome =
Chemical Co of Yarm in England. I was warned to take care not to get any =
residues from the machinery I was working with into cuts or abrasions =
since it would prevent these from healing and could lead to a cancer.
Why would ladies use this material as a mascara or cosmetic. Vanity. =
After all they used Arsenic Pentoxide freely for centuries, so why not =
Chrome Green in this day and age?
Best regards,
Ivor Lewis
Ron Roy on sun 29 dec 02
Chrome vaporizes when fired - avoid the fumes from your kilns - even if
there is no chrome in your glazes.
Remember - many of the oxides we talk about are in clay and glaze materials
naturally - in trace amounts - best to use caution when you can - there is
new information coming out all the time.
The most recent I have read - lead is absorbed through the skin - the old
tests were done to soon after exposure to record any intake - the new study
proves it does,
RR
>If chrome is so bad why do some green eyeshadows list it as an
>ingredient!!!?- definitely an argument to avoid the stuff!
>Steph
>----- Original Message -----
>From: "Lesley Alexander"
>To:
>Sent: Tuesday, December 17, 2002 8:37 AM
>Subject: Chrome
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
Edouard Bastarache on sun 29 dec 02
Hello all,
" The most recent I have read - lead is absorbed through the skin - the old
tests were done to soon after exposure to record any intake - the new study
proves it does,
(......)
RR"
Absorption :
Inorganic lead is not absorbed through intact skin but, only by the
respiratory and digestive tracts, except for metallic lead, which can
penetrate the skin in a negligible way.
"Ils sont fous ces Quebecois"
Edouard Bastarache
Irreductible Quebecois
Indomitable Quebeker
Sorel-Tracy
Quebec
edouardb@sorel-tracy.qc.ca
http://sorel-tracy.qc.ca/~edouardb/
http://perso.wanadoo.fr/smart2000/index.htm
Ivor on mon 29 dec 03
Ron is right.
I have had neat green shadows appear on the bat wash around a
white disk where the pot stood. This is at Cone 6 using 1 or 2%
green chrome oxide in the glaze.
Paradoxically pots with 5% tin in the same kiln have not blushed!
Ivor
Ivor J Townshend
Macclesfield UK
iandol on wed 31 dec 03
Ivor from Macclesfield wrote <<..I have had neat green shadows appear on =
the bat wash around a white disk where the pot stood. This is at Cone 6 =
using 1 or 2% green chrome oxide in the glaze.>>
Perhaps it should not be assumed that this phenomenon was due to =
"Volatilisation".=20
Some solids "decrepitate", that is explode into minute fragments when =
they are heated. The do not turn into gas or vapour. Which of the =
ingredients of a glaze do this is uncertain but it is known to happen to =
some crystalline solids. Common Salt, Sodium Chloride being a well known =
example.
Best regards,
Ivor Lewis. Redhill, South Australia
Ivor on thu 1 jan 04
Ivor Lewis wrote
>>Some solids "decrepitate", that is explode into
minute fragments when they are heated. The do not
turn into gas or vapour.
The green shadows that I get are extremely smooth
and uniform - no speckles visible to the naked eye.
If they are produced by solid particles rather than a
vapour, then the particles must be exceeding small
and uniformly emitted. Perhaps smoke might be a
better description.
Ivor
Ivor J Townshend
Macclesfield UK
Ron Roy on fri 2 jan 04
There have been many reports of tin glazes turning pink over the years -
many right here on clayart - there is no doubt that chrome is volatile -
the questions are - how much do we need to inhale before it's a problem and
what is our personal susceptibility.
RR
>Ivor from Macclesfield wrote <<..I have had neat green shadows appear on
>the bat wash around a white disk where the pot stood. This is at Cone 6
>using 1 or 2% green chrome oxide in the glaze.>>
>Perhaps it should not be assumed that this phenomenon was due to
>"Volatilisation".
>Some solids "decrepitate", that is explode into minute fragments when they
>are heated. The do not turn into gas or vapour. Which of the ingredients
>of a glaze do this is uncertain but it is known to happen to some
>crystalline solids. Common Salt, Sodium Chloride being a well known
>example.
>Best regards,
>Ivor Lewis. Redhill, South Australia
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
lili krakowski on wed 21 apr 10
Be aware, all of you making chrome based patinas that you must protect =3D
your skin, eyes, and respiratory system from the nasty stuff. And of =3D
course, do not ingest.
Lili Krakowski
Be of good courage
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