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Talc, or talcum, is a
clay mineral Clay minerals are hydrous aluminium phyllosilicates (e.g. kaolin, Al2 Si2 O5( OH)4), sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths, and other cations found on or near some planetary surfaces. Clay minera ...
composed of
hydrate In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understo ...
d
magnesium Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...
silicate A silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula , where . The family includes orthosilicate (), metasilicate (), and pyrosilicate (, ). The name is also used ...
, with the
chemical formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...
. Talc in powdered form, often combined with
corn starch Cornflour, cornstarch, maize starch, or corn starch (American English) is the starch derived from corn (maize) grain. The starch is obtained from the endosperm of the seed, kernel. Corn starch is a common food ingredient, often used to thick ...
, is used as
baby powder Baby powder is an astringent powder (substance), powder used for preventing diaper rash and for Cosmetics, cosmetic uses. It may be composed of talc (in which case it is also called talcum powder), corn starch or potato starch. It may contain a ...
. This mineral is used as a thickening agent and
lubricant A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, ...
. It is an ingredient in
ceramic A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcela ...
s,
paint Paint is a material or mixture that, when applied to a solid material and allowed to dry, adds a film-like layer. As art, this is used to create an image or images known as a painting. Paint can be made in many colors and types. Most paints are ...
s, and roofing material. It is a main ingredient in many
cosmetics Cosmetics are substances that are intended for application to the body for cleansing, beautifying, promoting attractiveness, or altering appearance. They are mixtures of chemical compounds derived from either Natural product, natural source ...
. It occurs as foliated to fibrous masses, and in an exceptionally rare
crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...
form. It has a perfect basal cleavage and an uneven flat fracture, and it is foliated with a two-dimensional platy form. The
Mohs scale The Mohs scale ( ) of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by the Ger ...
of mineral hardness, based on scratch
hardness comparison A variety of hardness-testing methods are available, including the Vickers, Brinell, Rockwell, Meyer and Leeb tests. Although it is impossible in many cases to give an exact conversion, it is possible to give an approximate material-specific co ...
, defines value 1 as the hardness of talc, the softest mineral. When scraped on a streak plate, talc produces a white streak, though this indicator is of little importance, because most silicate minerals produce a white streak. Talc is translucent to opaque, with colors ranging from whitish grey to green with a vitreous and pearly luster. Talc is not soluble in water, and is slightly soluble in dilute
mineral acid A mineral acid (or inorganic acid) is an acid derived from one or more inorganic compounds, as opposed to organic acids which are acidic, organic compounds. All mineral acids form hydrogen ions and the conjugate base when dissolved in water. Ch ...
s. Soapstone is a
metamorphic rock Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, caus ...
composed predominantly of talc.


Etymology

The word ''talc'' derives from ''tālk''. In ancient times, the word was used for various related minerals, including talc,
mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into fragile elastic plates. This characteristic is described as ''perfect basal cleavage''. Mica is co ...
, and selenite.


Formation

Talc dominantly forms from the metamorphism of magnesian minerals such as serpentine,
pyroxene The pyroxenes (commonly abbreviated Px) are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents ions of calcium (Ca), sodium (Na), iron ( ...
,
amphibole Amphibole ( ) is a group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Its IMA symbol is ...
, and
olivine The mineral olivine () is a magnesium iron Silicate minerals, silicate with the chemical formula . It is a type of Nesosilicates, nesosilicate or orthosilicate. The primary component of the Earth's upper mantle (Earth), upper mantle, it is a com ...
, in the presence of carbon dioxide and water. This is known as "talc carbonation" or "steatization" and produces a suite of rocks known as talc carbonates. Talc is primarily formed by hydration and carbonation by this reaction: : + → + + Talc can also be formed via a reaction between dolomite and silica, which is typical of skarnification of dolomites by silica-flooding in contact metamorphic aureoles: : + + → + + Talc can also be formed from magnesium chlorite and quartz in blueschist and eclogite metamorphism by the following metamorphic reaction: :
chlorite The chlorite ion, or chlorine dioxide anion, is the halite (oxyanion), halite with the chemical formula of . A chlorite (compound) is a compound that contains this group, with chlorine in the oxidation state of +3. Chlorites are also known as s ...
+
quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...
kyanite + talc + water Talc is also found as a diagenetic mineral in sedimentary rocks where it can form from the transformation of metastable hydrated magnesium-clay precursors such as kerolite, sepiolite, or stevensite that can precipitate from marine and lake water in certain conditions. In this reaction, the ratio of talc and kyanite depends on
aluminium Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...
content, with more aluminous rocks favoring production of kyanite. This is typically associated with high-pressure, low-temperature minerals such as phengite,
garnet Garnets () are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. Garnet minerals, while sharing similar physical and crystallographic properties, exhibit a wide range of chemical compositions, de ...
, and glaucophane within the lower blueschist facies. Such rocks are typically white, friable, and fibrous, and are known as whiteschist. Talc is a trioctahedral layered mineral; its structure is similar to pyrophyllite, but with magnesium in the octahedral sites of the composite layers. The crystal structure of talc is described as ''TOT'', meaning that it is composed of parallel ''TOT'' layers weakly bonded to each other by weak
van der Waals force In molecular physics and chemistry, the van der Waals force (sometimes van der Waals' force) is a distance-dependent interaction between atoms or molecules. Unlike ionic or covalent bonds, these attractions do not result from a chemical elec ...
s. The ''TOT'' layers in turn consist of two tetrahedral sheets (''T'') strongly bonded to the two faces of a single trioctahedral sheet (''O''). It is the weak bonding between ''TOT'' layers that gives talc its perfect basal cleavage and softness. The tetrahedral sheets consist of silica tetrahedra, which are silicon ions surrounded by four oxygen ions. The tetrahedra each share three of their four oxygen ions with neighboring tetrahedra to produce a hexagonal sheet. The remaining oxygen ion (the ''apical'' oxygen ion) is available to bond with the trioctahedral sheet. The trioctahedral sheet has the structure of a sheet of the mineral
brucite Brucite is the mineral form of magnesium hydroxide, with the chemical formula Magnesium, Mg(hydroxyl, OH)2. It is a common alteration product of periclase in marble; a low-temperature hydrothermal Vein (geology), vein mineral in metamorphosed li ...
. Apical oxygens take the place of some of the hydroxyl ions that would be present in a brucite sheet, bonding the tetrahedral sheets tightly to the trioctahedral sheet. Tetrahedral sheets have a negative charge, since their bulk composition is . The trioctahedral sheet has an equal positive charge, since its bulk composition is The combined TOT layer thus is electrically neutral. Because the hexagons in the T and O sheets are slightly different in size, the sheets are slightly distorted when they bond into a TOT layer. This breaks the hexagonal symmetry and reduces it to monoclinic or triclinic symmetry. However, the original hexahedral symmetry is discernible in the pseudotrigonal character of talc crystals. File:Mica T.png, View of tetrahedral sheet structure of talc. The apical oxygen ions are tinted pink. File:Talc to.jpg, View of trioctahedral sheet of talc. Yellow spheres are hydroxyl; blue are magnesium. Apical oxygen binding sites are white. File:Talc structure.jpg, Talc crystal viewed along the 00axis, looking along the layers of the crystal


Occurrence

Talc is a common metamorphic mineral in metamorphic belts that contain ultramafic rocks, such as soapstone (a high-talc rock), and within whiteschist and blueschist metamorphic
terrane In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust fragment formed on a tectonic plate (or broken off from it) and accreted or " sutured" to crust lying on another plate. The crustal block or fragment preserves its d ...
s. Prime examples of whiteschists include the Franciscan Metamorphic Belt of the western United States, the western European
Alps The Alps () are some of the highest and most extensive mountain ranges in Europe, stretching approximately across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia. ...
especially in Italy, certain areas of the Musgrave Block, and some collisional orogens such as the
Himalayas The Himalayas, or Himalaya ( ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the Earth's highest peaks, including the highest, Mount Everest. More than list of h ...
, which stretch along
Pakistan Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ...
,
India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
,
Nepal Nepal, officially the Federal Democratic Republic of Nepal, is a landlocked country in South Asia. It is mainly situated in the Himalayas, but also includes parts of the Indo-Gangetic Plain. It borders the Tibet Autonomous Region of China Ch ...
, and
Bhutan Bhutan, officially the Kingdom of Bhutan, is a landlocked country in South Asia, in the Eastern Himalayas between China to the north and northwest and India to the south and southeast. With a population of over 727,145 and a territory of , ...
. Talc carbonate ultramafics are typical of many areas of the Archaean
craton A craton ( , , or ; from "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two topmost layers, the crust and the uppermost mantle. Having often survived cycles of merging and rifting of contine ...
s, notably the komatiite belts of the Yilgarn craton in
Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...
. Talc-carbonate ultramafics are also known from the Lachlan Fold Belt, eastern
Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
, from
Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
, the Guiana Shield, and from the
ophiolite An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle (Earth), upper mantle that has been uplifted and exposed, and often emplaced onto continental crustal rocks. The Greek word ὄφις, ''ophis'' (''snake'') is ...
belts of
Turkey Turkey, officially the Republic of Türkiye, is a country mainly located in Anatolia in West Asia, with a relatively small part called East Thrace in Southeast Europe. It borders the Black Sea to the north; Georgia (country), Georgia, Armen ...
,
Oman Oman, officially the Sultanate of Oman, is a country located on the southeastern coast of the Arabian Peninsula in West Asia and the Middle East. It shares land borders with Saudi Arabia, the United Arab Emirates, and Yemen. Oman’s coastline ...
, and the
Middle East The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq. The term came into widespread usage by the United Kingdom and western Eur ...
. China is the key world talc and steatite-producing country with an output of about 2.2 million tonnes (2016), which accounts for 30% of total global output. The other major producers are Brazil (12%), India (11%), the U.S. (9%), France (6%), Finland (4%), Italy, Russia, Canada, and Austria (2%, each). Notable economic talc occurrences include the Mount Seabrook talc mine, Western Australia, formed upon a polydeformed, layered ultramafic intrusion. The France-based Luzenac Group is the world's largest supplier of mined talc. Its largest talc mine at Trimouns near Luzenac in southern France produces 400,000 tonnes of talc per year.


Conflict mineral

Extraction in disputed areas of
Nangarhar province Nangarhār (Pashto: ; Dari: ), also called Nangrahar or Ningrahar, is one of the 34 provinces of Afghanistan, located in the eastern part of the country and Border, bordering Logar Province, Logar, Kabul Province, Kabul, Laghman Province, Laghm ...
, Afghanistan, has led the international monitoring group Global Witness to declare talc a
conflict resource A resource war is a type of war caused by conflict over resources. In a resource war, there is typically a nation or group that controls the resource and an aggressor that wishes to seize control over said resource. This power dynamic between nati ...
, as the profits are used to fund armed confrontation between the
Taliban , leader1_title = Supreme Leader of Afghanistan, Supreme leaders , leader1_name = {{indented plainlist, * Mullah Omar{{Natural Causes{{nbsp(1994–2013) * Akhtar Mansour{{Assassinated (2015–2016) * Hibatullah Akhundzada (2016–present) ...
and
Islamic State The Islamic State (IS), also known as the Islamic State of Iraq and the Levant (ISIL), the Islamic State of Iraq and Syria (ISIS) and Daesh, is a transnational Salafi jihadism, Salafi jihadist organization and unrecognized quasi-state. IS ...
.


Uses

Talc is used in many industries, including paper making,
plastic Plastics are a wide range of synthetic polymers, synthetic or Semisynthesis, semisynthetic materials composed primarily of Polymer, polymers. Their defining characteristic, Plasticity (physics), plasticity, allows them to be Injection moulding ...
, paint and coatings (e.g. for metal casting molds), rubber, food, electric cable, pharmaceuticals, cosmetics, and ceramics. A coarse grayish-green high-talc rock is soapstone or steatite, used for stoves, sinks, electrical switchboards, etc. It is often used for surfaces of laboratory table tops and electrical switchboards because of its resistance to heat, electricity, and acids. In finely ground form, talc finds use as a cosmetic (talcum powder), as a
lubricant A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, ...
, and as a filler in paper manufacture. It is used to coat the insides of inner tubes and rubber gloves during manufacture to keep the surfaces from sticking. Talcum powder, with heavy refinement, has been used in baby powder, an astringent powder used to prevent diaper rash (nappy rash). The
American Academy of Pediatrics The American Academy of Pediatrics (AAP) is the largest professional association of pediatricians in the United States. It is headquartered in Itasca, Illinois, and maintains an office in Washington, D.C. The AAP has published hundreds of poli ...
recommends that parents avoid using baby powder because it poses a risk of respiratory problems, including breathing trouble and serious lung damage if inhaled. The small size of the particles makes it difficult to keep them out of the air while applying the powder.
Zinc oxide Zinc oxide is an inorganic compound with the Chemical formula, formula . It is a white powder which is insoluble in water. ZnO is used as an additive in numerous materials and products including cosmetics, Zinc metabolism, food supplements, rubbe ...
-based ointments are a much safer alternative. Soapstone (massive talc) is often used as a marker for
welding Welding is a fabrication (metal), fabrication process that joins materials, usually metals or thermoplastics, primarily by using high temperature to melting, melt the parts together and allow them to cool, causing Fusion welding, fusion. Co ...
or
metalworking Metalworking is the process of shaping and reshaping metals in order to create useful objects, parts, assemblies, and large scale structures. As a term, it covers a wide and diverse range of processes, skills, and tools for producing objects on e ...
. Talc is also used as
food additive Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives, such as vinegar ( pickling), salt ( salting), smoke ( smoking) and sugar ( crystallization), have been used f ...
or in pharmaceutical products as a glidant. In medicine, talc is used as a pleurodesis agent to prevent recurrent pleural effusion or
pneumothorax A pneumothorax is collection of air in the pleural space between the lung and the chest wall. Symptoms typically include sudden onset of sharp, one-sided chest pain and dyspnea, shortness of breath. In a minority of cases, a one-way valve is ...
. In the
European Union The European Union (EU) is a supranational union, supranational political union, political and economic union of Member state of the European Union, member states that are Geography of the European Union, located primarily in Europe. The u ...
, the additive number is E553b. Talc may be used in the processing of white
rice Rice is a cereal grain and in its Domestication, domesticated form is the staple food of over half of the world's population, particularly in Asia and Africa. Rice is the seed of the grass species ''Oryza sativa'' (Asian rice)—or, much l ...
as a buffing agent in the polishing stage. Due to its low shear strength, talc is one of the oldest known solid lubricants. Also, limited use is made of talc as a friction-reducing additive in lubricating oils. Talc is widely used in the ceramics industry in both bodies and glazes. In low-fire art-ware bodies, it imparts whiteness and increases thermal expansion to resist crazing. In
stoneware Stoneware is a broad class of pottery fired at a relatively high temperature, to be impervious to water. A modern definition is a Vitrification#Ceramics, vitreous or semi-vitreous ceramic made primarily from stoneware clay or non-refractory fire ...
s, small percentages of talc are used to flux the body and therefore improve strength and
vitrification Vitrification (, via French ') is the full or partial transformation of a substance into a glass, that is to say, a non- crystalline or amorphous solid. Glasses differ from liquids structurally and glasses possess a higher degree of connectivity ...
. It is a source of MgO flux in high-temperature glazes (to control melting temperature). It is also employed as a matting agent in earthenware glazes and can be used to produce magnesia mattes at high temperatures. ISO standard for quality (ISO 3262) Patents are pending on the use of magnesium silicate as a cement substitute. Its production requirements are less energy-intensive than ordinary
Portland cement Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar (masonry), mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in th ...
(at a heating requirement of around 650 °C for talc compared to 1,500 °C for limestone to produce Portland cement), while it absorbs far more
carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...
as it hardens. This results in a negative
carbon footprint A carbon footprint (or greenhouse gas footprint) is a calculated value or index that makes it possible to compare the total amount of greenhouse gases that an activity, product, company or country Greenhouse gas emissions, adds to the atmospher ...
overall, as the cement substitute removes 0.6 tonnes of CO2 per tonne used. This contrasts with a positive carbon footprint of 0.4 tonnes per tonne of conventional cement.Jha, Alok (31 December 2008
Revealed: The cement that eats carbon dioxide
''The Guardian''
Talc is used in the production of the materials that are widely used in the building interiors such as base content
paint Paint is a material or mixture that, when applied to a solid material and allowed to dry, adds a film-like layer. As art, this is used to create an image or images known as a painting. Paint can be made in many colors and types. Most paints are ...
s in wall coatings. Other areas that use talc to a great extent are organic
agriculture Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created ...
, the food industry, cosmetics, and hygiene products such as baby powder and detergent powder. Talc is sometimes used as an adulterant to illegal
heroin Heroin, also known as diacetylmorphine and diamorphine among other names, is a morphinan opioid substance synthesized from the Opium, dried latex of the Papaver somniferum, opium poppy; it is mainly used as a recreational drug for its eupho ...
, to expand volume and weight and thereby increase its street value. With
intravenous Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutr ...
use, it may lead to pulmonary talcosis, a
granuloma A granuloma is an aggregation of macrophages (along with other cells) that forms in response to chronic inflammation. This occurs when the immune system attempts to isolate foreign substances that it is otherwise unable to eliminate. Such sub ...
tous inflammation in the
lung The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...
s.


Sterile talc powder

Sterile talc powder ( NDC 63256-200-05) is a sclerosing agent used in the procedure of pleurodesis. This can be helpful as a cancer treatment to prevent pleural effusions (an abnormal collection of fluid in the space between the
lung The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...
s and the thoracic wall). It is inserted into the space via a chest tube, causing it to close up, so fluid cannot collect there. The product can be sterilized by dry heat,
ethylene oxide Ethylene oxide is an organic compound with the chemical formula, formula . It is a cyclic ether and the simplest epoxide: a three-membered ring (chemistry), ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless ...
, or gamma irradiation.


Safety

Suspicions have been raised that talc use contributes to certain types of disease, mainly cancers of the ovaries and lungs. According to the IARC, talc containing asbestos is classified as a group 1 agent (carcinogenic to humans), talc use in the
perineum The perineum (: perineums or perinea) in placentalia, placental mammals is the space between the anus and the genitals. The human perineum is between the anus and scrotum in the male or between the anus and vulva in the female. The perineum is ...
is classified as group 2B (possibly carcinogenic to humans), and talc not containing asbestos is classified as group 2A (probably carcinogenic to humans). Reviews by
Cancer Research UK Cancer Research UK (CRUK) is the world's largest independent cancer research organisation. It is registered as a charity in the United Kingdom and Isle of Man, and was formed on 4 February 2002 by the merger of The Cancer Research Campaign and t ...
and the
American Cancer Society The American Cancer Society (ACS) is a nationwide non-profit organization dedicated to eliminating cancer. The ACS publishes the journals ''Cancer'', '' CA: A Cancer Journal for Clinicians'' and '' Cancer Cytopathology''. History The society w ...
conclude that some studies have found a link, but other studies have not. The studies discuss pulmonary issues,
lung cancer Lung cancer, also known as lung carcinoma, is a malignant tumor that begins in the lung. Lung cancer is caused by genetic damage to the DNA of cells in the airways, often caused by cigarette smoking or inhaling damaging chemicals. Damaged ...
, and ovarian cancer. One of these, published in 1993, was a US National Toxicology Program report, which found that cosmetic grade talc containing no
asbestos Asbestos ( ) is a group of naturally occurring, Toxicity, toxic, carcinogenic and fibrous silicate minerals. There are six types, all of which are composed of long and thin fibrous Crystal habit, crystals, each fibre (particulate with length su ...
-like fibres was correlated with tumor formation in
rat Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include '' Neotoma'' (pack rats), '' Bandicota'' (bandicoo ...
s forced to inhale talc for 6 hours a day, five days a week over at least 113 weeks. A 1971 paper found particles of talc embedded in 75% of the ovarian tumors studied. In 2018,
Health Canada Health Canada (HC; )Health Canada is the applied title under the Federal Identity Program; the legal title is Department of Health (). is the Structure of the Canadian federal government#Departments, with subsidiary units, department of the Gove ...
issued a warning against inhaling talcum powder or women's using it perineally. In contrast, however, research published in 1995 and 2000 concluded that, although it was plausible that talc could cause ovarian cancer, no conclusive evidence had been shown. Further, a 2008 European Journal of Cancer Prevention review of ovarian cancer and talc use studies pointed out that, although many of them examined the duration, frequency, and accumulation of hygienic talc use, few found a positive association among these factors and some found a negative one: “It may be argued that the overall null findings associated with talc-dusted diaphragms and condom use is more convincing evidence for a lack of a carcinogenic effect, especially given the lack of an established correlation between perineal dusting frequency and ovarian tissue talc concentrations and the lack of a consistent dose-response relationship with ovarian cancer risk." Instead, the authors credited powdered talc with "a high degree of safety.” Similarly, in a 2014 article published in a leading cancer journal, the Journal of the National Cancer Institute, researchers reported the results of a survey of 61,576 postmenopausal women, more than half of whom had used talc powder perineally. The researchers compared the subjects’ reports of their own talc use with their reports of having had ovarian cancer diagnosed by their doctors, and found, regardless of subjects’ age and tubal ligation status, “Ever use of perineal powder ... was not associated with risk of ovarian cancer compared with never use,” nor was any greater individual cancer risk associated with longer use of talc powder. On this basis, the article concluded, “perineal powder use does not appear to influence ovarian cancer risk.” The Cosmetic Ingredient Review Expert Panel concluded in 2015 that talc, in the concentrations currently used in cosmetics, is safe. In July 2024, the
International Agency for Research on Cancer The International Agency for Research on Cancer (IARC; ) is an intergovernmental agency forming part of the World Health Organization of the United Nations. Its role is to conduct and coordinate research into the causes of cancer. It also cance ...
listed talc as "probably"
carcinogenic A carcinogen () is any agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and Biological agent, biologic agent ...
for humans. The study is based on limited evidence it could cause ovarian cancer in humans.


Industrial grade

In the United States, the
Occupational Safety and Health Administration The Occupational Safety and Health Administration (OSHA; ) is a regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. The United States Congress established ...
and
National Institute for Occupational Safety and Health The National Institute for Occupational Safety and Health (NIOSH, ) is the List of United States federal agencies, United States federal agency responsible for conducting research and making recommendations for the prevention of work-related occ ...
have set occupational exposure limits to respirable talc dusts at 2 mg/m3 over an eight-hour workday. At levels of 1000 mg/m3, inhalation of talc is considered immediately dangerous to life and health.


Food grade

The United States
Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...
considers talc (magnesium silicate)
generally recognized as safe Generally recognized as safe (GRAS) is a United States Food and Drug Administration (FDA) designation that a chemical or substance added to food is considered safe by experts under the conditions of its intended use. An ingredient with a GRAS d ...
(GRAS) to use as an
anticaking agent An anticaking agent is an additive placed in powdered or granulated materials, such as table salt or confectioneries, to prevent the formation of lumps ( caking) and for easing packaging, transport, flowability, and consumption. Caking mechanism ...
in table salt in concentrations smaller than 2%.


Association with asbestos

One particular issue with commercial use of talc is its frequent co-location in underground deposits with
asbestos Asbestos ( ) is a group of naturally occurring, Toxicity, toxic, carcinogenic and fibrous silicate minerals. There are six types, all of which are composed of long and thin fibrous Crystal habit, crystals, each fibre (particulate with length su ...
ore. Asbestos is a general term for different types of fibrous silicate minerals, desirable in construction for their heat resistant properties. There are six varieties of asbestos; the most common variety in manufacturing, white asbestos, is in the serpentine family. Serpentine minerals are sheet silicates; although not in the serpentine family, talc is also a sheet silicate, with two sheets connected by magnesium cations. The frequent co-location of talc deposits with asbestos may result in contamination of mined talc with white asbestos, which poses serious health risks when dispersed into the air and inhaled. Stringent quality control since 1976, including separating cosmetic- and food-grade talc from that destined for industrial use, has largely eliminated this issue, but it remains a potential hazard requiring mitigation in the mining and processing of talc. A 2010 US FDA survey failed to find asbestos in a variety of talc-containing products. A 2018
Reuters Reuters ( ) is a news agency owned by Thomson Reuters. It employs around 2,500 journalists and 600 photojournalists in about 200 locations worldwide writing in 16 languages. Reuters is one of the largest news agencies in the world. The agency ...
investigation asserted that pharmaceuticals company
Johnson & Johnson Johnson & Johnson (J&J) is an American multinational pharmaceutical, biotechnology, and medical technologies corporation headquartered in New Brunswick, New Jersey, and publicly traded on the New York Stock Exchange. Its common stock is a c ...
knew for decades that there was asbestos in its baby powder, and in 2020 the company stopped selling its baby powder in the US and Canada. There were calls for Johnson & Johnson's largest shareholders to force the company to end global sales of baby powder, and hire an independent firm to conduct a racial justice audit as it had been marketed to African American and overweight women. On August 11, 2022, the company announced it would stop making talc-based powder by 2023 and replace it with cornstarch-based powders. The company said the talc-based powder is safe to use and does not contain asbestos.


Litigation

In 2006 the
International Agency for Research on Cancer The International Agency for Research on Cancer (IARC; ) is an intergovernmental agency forming part of the World Health Organization of the United Nations. Its role is to conduct and coordinate research into the causes of cancer. It also cance ...
classified talcum powder as a possible human carcinogen if used in the female genital area. Despite this, no federal agency in the US acted to remove talcum powder from the market or add warnings. In February 2016, as the result of a lawsuit against
Johnson & Johnson Johnson & Johnson (J&J) is an American multinational pharmaceutical, biotechnology, and medical technologies corporation headquartered in New Brunswick, New Jersey, and publicly traded on the New York Stock Exchange. Its common stock is a c ...
(J&J), a St. Louis jury awarded $72 million to the family of an Alabama woman who died from ovarian cancer. The family claimed that the use of talcum powder was responsible for her cancer. In May 2016, a South Dakota woman was awarded $55 million as the result of another lawsuit against J&J. The woman had used Johnson & Johnson's
Baby Powder Baby powder is an astringent powder (substance), powder used for preventing diaper rash and for Cosmetics, cosmetic uses. It may be composed of talc (in which case it is also called talcum powder), corn starch or potato starch. It may contain a ...
for more than 35 years before being diagnosed with ovarian cancer in 2011. In October 2016, a St. Louis jury awarded $70.1 million to a Californian woman with ovarian cancer who had used Johnson's Baby Powder for 45 years.Does baby powder cause cancer? Another jury thinks so, awarding $70 million to a California woman
''
LA Times The ''Los Angeles Times'' is an American daily newspaper that began publishing in Los Angeles, California, in 1881. Based in the Greater Los Angeles city of El Segundo since 2018, it is the sixth-largest newspaper in the U.S. and the large ...
'' (2016-10-28). Retrieved on 2017-05-06.
In August 2017, a Los Angeles jury awarded $417 million to a Californian woman, Eva Echeverria, who developed ovarian cancer as a "proximate result of the unreasonably dangerous and defective nature of talcum powder", her lawsuit against Johnson & Johnson stated. On 20 October 2017, Los Angeles Superior Court judge Maren Nelson dismissed the verdict. The judge stated that Echeverria proved there is "an ongoing debate in the scientific and medical community about whether talc more probably than not causes ovarian cancer and thus (gives) rise to a duty to warn", but not enough to sustain the jury's imposition of liability against Johnson & Johnson stated, and concluded that Echeverria did not adequately establish that talc causes ovarian cancer. In July 2018, a court in St. Louis awarded a $4.7bn claim ($4.14bn in punitive damages and $550m in compensatory damages) against J&J to 22 claimant women, concluding that the company had suppressed evidence of
asbestos Asbestos ( ) is a group of naturally occurring, Toxicity, toxic, carcinogenic and fibrous silicate minerals. There are six types, all of which are composed of long and thin fibrous Crystal habit, crystals, each fibre (particulate with length su ...
in its products for more than four decades. At least 1,200 to 2,000 other talcum powder-related lawsuits were pending . In 2020 J&J stopped sales of its talcum-based baby powder, which it had been selling for 130 years. J&J created a subsidiary responsible for the claims in an effort to resolve the lawsuits in bankruptcy court. In 2023 J&J proposed a nearly $9bn settlement with 50,000 claimants saying the claims were "specious" but it wanted to move on from the issue, but judges blocked the plans, ruling that the subsidiary was not in financial distress and could not use the bankruptcy system to resolve the lawsuits. In July 2023 J&J sued researchers who linked talc to cancer alleging they used junk science to disparage company's products, while defendants say the lawsuits are meant to silence scientists.


See also

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References

{{Authority control Phyllosilicates Magnesium minerals Symbols of Vermont Cosmetics chemicals Excipients IARC Group 2A carcinogens Clay minerals group Triclinic minerals Minerals in space group 2 Monoclinic minerals Minerals in space group 15 Luminescent minerals E-number additives