Talc Toxicology
By Edouard Bastarache
Introduction :
Talc as a pure chemical compound is a
hydrous magnesium silicate, [Mg6 (Si8O20) (OH4)], that exists in
sheetlike crystalline forms or as fibers. The purity and physical
form of any sample depends on the source of the talc and on the
minerals found in the ore body from which it is refined. Talc can
exist in many forms and depending on the ore source in can be
found in a pure form or mixed with asbestos or silica. Talc used
in industrial settings can contain mixtures of silica, amphibole
asbestos, tremolite, actinolite, and anthophyllite. Exposure to
low-grade talc may give rise to talcosilicosis or talcoasbestosis,
in which cases the disease will exhibit the features of silicosis
or asbestosis, respectively.
Inhalation talc exposure can result
in :
-talco-asbestosis,
-talco-silicosis,
-pure talcosis.
Talco-Asbestosis :
Talco-asbestosis closely resembles
asbestosis and is produced by crystalline talc, generally inhaled
with asbestos fibers. Pathologic and radiographic abnormalities
are virtually identical with those of asbestosis, including
calcifications and malignant tumor formation.
Talc containing more than 1% asbestos is
considered a human carcinogen.
Talco-Silicosis :
The first form, talco-silicosis, is
caused by talc mined with high-silica-content mineral. Findings in
this form are identical with those of silicosis.
Pure Talcosis :
This type of talc is less fibrogenic
than the others.
Pure talcosis results from the
inhalation of pure talc without contamination from other
mineral sources. It is found in
occupational and non-occupational settings associated with
cosmetic use of talcum powder.
Excessive use of talcum powder, as well
as the accidental aspiration of talc by infants, has been
associated with diffuse irregular opacities throughout the upper
or lower lung fields, focal fibrosis of the small airways,
bronchiolitis, and extensive fibrosis with granuloma formation.
On tissue examination, fibrosis, foreign
body granulomas, and multinucleated giant cells are seen.
Radiologic abnormalities include round
or irregular opacities.
Physiologic pulmonary testing reveals
normal, restrictive, or mixed restrictive and obstructive
abnormalities in pulmonary function.
In animals pure talc induces a cytogenic
rather than fibrogenic effect on the lungs.
Intravenous Form :
The fourth form, due to intravenous
administration of talc, is usually associated with abuse of oral
medications and production of vascular granulomas manifested by
consolidations, large nodules, and masses. Talcosis may also
present as a granulomatous pneumonitis and give rise to a
radiological appearance of sarcoidosis or miliary tuberculosis.
Such foreign body granulomas are seen especially (but not only) in
intravenous drug addicts as result of the injection of crushed
talc-containing tablets.
Here are a few toxicologic data
sheets made available to us by The Répertoire Toxicologique
de la Commission de la Santé et Sécurité du
Travail du Québec :
Fibrous
Talc
Identification :
Main Synonyms :
French names :
Talc (fibreux)
TALC FIBREUX
English names :
Talc, fibrous
FIBROUS TALC
Use and Sources of Emission
:
Manufacture of pharmaceutical products,
pharmaceutical product.
Hygiene and safety
:
I-Appearance :
Solid fibrous, white-gray, odourless
II-Physical Properties :
A-Physical State : Solid
B-Solubility in Water : 0,00 g/l at 20
°C
C-Melting Point : 0,00 °C
D-Boiling Point : 0,00 °C
III-Inflammability and Explosiveness
Inflammability :
This product is non flammable.
Prevention :
I-Reactivity :
A-Stability :
This product is stable.
B-Incompatibility :
No known incompatibility.
C-Products of Decomposition
Information nonavailable
II-Handling :
Avoid any contact with the skin. Wear
suitable eye protection. In the case of insufficient ventilation,
wear a suitable breathing apparatus.
III-Storage :
Store in an airtight container.
IV-Leaks :
Collect in a hermetic container duly
identified by using a suitable technique in order to prevent the
contamination of the environment.
V-Waste Disposal :
Consult with the regional
authority.
Toxicology :
I-Absorption :
This product is absorbed by the
respiratory tract.
II-Chronic Effects :
-pulmonary fibrosis,
-pneumoconiosis,
-granulomatosis.
Cancerogenic Effects
Cancerogenic to human beings.
First aid :
In the event of inhalation of vapors or
dust, bring the person into a ventilated place.
Quebec's Exposure Limit :
I-Valeur d'exposition moyenne
pondérée (VEMP) :
1 Fiber/cm³ (Respirable)
II-Notations :
C1 : Cancerogenic effet demonstrated in
human beings.
EM : The exposure to this substance must
be reduced to a minimum.
Non Fibrous Talc
(Pure)
Identification :
CAS Number : 14807-96-6
Molecular Formula: H2Mg3O12Si4
Main Synonyms :
French names :
Talc (non fibreux)
Poudre de talc
Talc
English Names :
Talc, not fibrous
Cosmetic talc.
Comment :
This product can contain quartz
(<1%)
Uses and Sources of Emission
:
Adsorption agent,
manufacture of pharmaceutical
products.
Hygiene and safety
:
I-Appearance :
Powdery, white, odourless.
II-Physical Properties :
A-State : Solid.
B-Molecular Mass : 379,3.
C-Density : 2,7 g/ml at 20 °C.
D-Solubility in Water : Insoluble.
E-Fusion Point : 950,00 °C.
III-Inflammability and
Explosiveness
Inflammability:
This product is non flammable.
Prevention :
I-Reactivity :
A-Stability :
This product is stable.
B-Incompatibility :
No known incompatibility for this
product.
C-Decomposition Products :
Information unavailable.
II-Handling :
Wear ocular protection, and in the case
of insufficient ventilation, a suitable breathing apparatus.
III-Storage :
Preserve in an airtight
container.
Preserve in a well ventilated place.
IV-Leaks :
Collect wastes and put them in a
dustbin.
V-Waste disposal :
Put in a dustbin.
Toxicology :
I-IDLH (Immediate danger to life and
health) :
1 000 mg/m³
II-Absorption :
This product is absorbed by the
respiratory and digestive tracts.
III-Acute Effects :
A-Possible irritation of :
- eyes,
- skin,
- respiratory tract (upper).
B-Digestive tract :
- nausea,
- diarrhoea.
IV-Chronic Effects :
- cough,
- benign pneumoconiosis,
- possible pulmonary fibrosis and
talcosis.
Effects on Development :
Several studies in several animal
species suggest the absence of effects on antenatal development.
Effects on Reproduction :
No data concerning the effects on
reproduction were found in the consulted documentary sources.
Data on Mother's Milk :
There is no data concerning its
excretion or detection in milk.
Cancerogenic Effects :
I-Evaluation by the I.A.R.C.
:
It cannot be classified as for its
cancerogenicity for man (group 3).
II-Evaluation by the A.C.G.I.H.
:
Substance not classifiable as
cancerogenic for man (A4 group).
Mutagenic effects :
Several studies in animal species
suggest the absence of a mutagenic effect.
First aid :
I-Ocular Contact :
Rinse eyes with plenty of water and see
a doctor. Wash skin with soap and water.
II-Ingestion :
Provoke vomiting if the patient is
conscious.
III-Inhalation :
Bring the person into a ventilated
place.
Quebec's exposure limit
:
Valeur d'exposition moyenne
pondérée (VEMP) :
Respirable dust : 3 (mg/m³)
Massive Talc
(Soapstone)
Identification :
CAS Number : 14378-12-2
Molecular Formula : H2MG3O12SI4
Main Synonyms :
French names :
Stéatite.
Pierre à savon.
English names:
Soapstone.
Massive talc.
Uses and Sources of Emission
:
Soapstone is a steatite stone and its
primary components are magnesite, dolomite, chlorite, and talc.
For thousands of years, soapstone has
been used throughout the world for tools, karafes, vases, goblets,
sculptures, fireplaces, etc.
In early American history, soapstone was
used primarily for building blocks, sculpting and urns.
In early New England, Soapstone uses
ranged fom fireplace hearths to countertops, sinks, and oven
fireplace stoves.
Currently in the USA and in different
parts of the world, soapstone is used for the largest variety of
items ever yet - including balusters, stair treads, window sills
and island tops.
For over one hundred years, soapstone
sinks and tiles have been used in science class rooms and labs
along with work tables and counter tops.
Its longevity to long term - high
traffic use is amazing!
Because of its truly remarkable and
natural heat retention characteristics, soapstone is widely used
for masonry heater fireplaces, wood stoves, fireplace liners and
pizza ovens.
It is also used as a colourant.
Hygiene and safety
:
I-Appearance :
Powdery, white, odourless.
II-Physical properties
A-Physical State : Solid.
B-Molecular Mass : 379,2.
C-Density : 2,75 g/ml at 20 °C.
D-Solubility in Water : Insoluble.
III-Inflammability and
Explosiveness
Inflammability : This product is non
flammable.
Prevention :
I-Reactivity :
A-Stability :
This product is stable.
B-Incompatibility :
No known incompatibility for this
product
C-Products of Decomposition
Information non available
II-Handling :
Ventilate adequately if not wear a
suitable breathing apparatus
III-Leaks :
Collect waste and put in a hermetic
container.
IV-Waste disposal :
Consult with the regional office of the
Department of the Environment.
Toxicology :
I-IDLH (Immediate Danger to Life and
Health) :
3 000 mg/m³
II-Absorption :
This product is absorbed by the
respiratory tract.
III- Chronic Effects
:
Fibrotic pneumoconiosis :
- cough,
- dyspnea, shortness of breath,
- cyanosis (blueing of extremities),
- deformity of the tips of the fingers
(digital hippocratism),
- obstruction of the alveoli,
- limitation of thoracic expansion,
- possible heart failure.
First aid
I-Eyes :
Rinse eyes with plenty of water.
II-Inhalation :
In the event of inhalation of vapors or
dust, bring the person into a ventilated place.
If he does not breathe, give the
artificial respiration.
Call a doctor.
Quebec's Exposure Limit
:
Valeur d'Exposition Moyenne
Pondérée (VEMP)
Respirable dust : 3 (mg/m³)
Total dust : 6 (mg/m³)
Note : The limit applies to dust not containing asbestos
and in which the percentage of crystalline silica is lower than 1
%.
References :
1-Occupational Medicine,Carl Zenz,
last edition.
2-Clinical Environmental Health and
Toxic Exposures, Sullivan & Krieger; last edition.
3-Sax's Dangerous Properties of
Industrial Materials, Lewis C., last edition.
4-Toxicologie Industrielle et
Intoxications Professionnelles, Lauwerys R.R. last
edition.
5-Chemical Hazards of the Workplace,
Proctor & Hughes, 4th edition
6-CSST-Québec, Service du
Répertoire Toxicologique, 2005
Edouard Bastarache M.D.
Occupational & Environmental Medicine
Author of "Substitutions for Raw Ceramic Materials"
Tracy, Québec, CANADA
edouardb@sorel-tracy.qc.ca
http://www.sorel-tracy.qc.ca/~edouardb/
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