Document ID: OSHA-2010-0034-3990
Agency: osha
Document Type: Supporting & Related Material
Title: 
Posted Date: 2014-06-04T04:00Z

The following information was generated from the 
Hazardous Substances Data Bank (HSDB),
a database of the National Library of Medicine's TOXNET system
(http://toxnet.nlm.nih.gov) on April 17, 2014.

Query: The chemical name bentonite was identified.
The following terms were added from ChemIDplus:
volclay
tixoton
southern bentonite
magbond
bentonite magma
bentonite  jan nf 
CAS Registry Number: 1302-78-9

1
NAME: BENTONITE

HSN: 392

RN: 1302-78-9

HUMAN HEALTH EFFECTS:

TOXICITY SUMMARY:
      IDENTIFICATION: Bentonite is a rock formed of highly colloidal and plastic
      clays composed mainly of montmorillonite and produced in situ
      devitrification of volcanic ash. It may contain feldspar, cristobalite and
      crystaline quartz. Major uses of bentonite include binding foundry sand in
      molds, absorbing grease, oil and animal wastes; palletizing taconite iron
      ore and improving the properties of drilling muds. It is used as an
      ingredient in ceramics, water proofing and sealing in civil engineering
      projects such as landfill sites and nuclear waste repositories, serving as
      a filter, stabilizer or extender in adhesives, paints, cosmetics and
      medicines. It is used as a bonding agent in animal feed, carrier for
      pesticides, clarifying wine and vegetable oil and purifying waste water.
      HUMAN EXPOSURE: In the view of widespread distribution of bentonite in
      nature and its use in various consumer products, general population
      exposure to low concentrations is ubiquitous. Occupational exposure to
      bentonite dust from mining, processing and user industries is a factor.
      ANIMAL STUDIES: Single intratracheal injection into rodents of bentonite
      and montmorillonite with low quartz content caused dose and particle side
      dependent effects, as well as transient local inflammation, which included
      edema and increased lung weight. Single intratracheal exposures of rats to
      bentonite caused storage foci in the lungs. After intratracheal exposure
      of rats to this material with high quartz content, fibrosis is noted. Mice
      maintained on diets containing bentonite displayed slightly reduced growth
      rates. Mice treated with higher doses showed minimal growth and fatty
      livers and fibrosis of the liver and benign hepatomas. Bentonite increased
      the susceptibility of mice to pulmonary infection. In vitro studies of the
      effects of bentonite on a variety of mammalian cell types indicated a high
      degree of cytotoxicity. Limited studies did not demonstrate developmental
      toxicity in rats after oral exposure to bentonite. No adequate studies are
      available on the carcinogenicity of bentonite.[[World Health
      Organization/International Programme on Chemical Safety; Environmental
      Heath Criteriia 231 Bentonite, Kaolin and Selected Clay Minerals pp. 1-5
      (2005)]] **PEER REVIEWED** 

HUMAN TOXICITY EXCERPTS:
      /HUMAN EXPOSURE STUDIES/ Effects of bentonite in workers in processing
      plant...very high incidence of bronchial asthma (25%) in workers examined,
      and attributed this to the irritant action of the bentonite dust on the
      bronchial epithelium.[Browning, E. Toxicity of Industrial Metals. 2nd ed.
      New York: Appleton-Century-Crofts, 1969., p. 9] **PEER REVIEWED** 

      /SIGNS AND SYMPTOMS/ /Investigators/ reported radiological evidence, not
      supported by autopsy, of significant damage to lungs following exposures
      to bentonite or montmorillonite dust of 10-42 years.[IPCS Environmental
      Health Criteria 231, Bentonite, Kaolin and selected clay minerals.
      Available from, as of April 5, 2013:
      http://www.inchem.org/documents/ehc/ehc/ehc231.htm] **PEER REVIEWED** 

      /CASE REPORTS/ Five workers exposed to bentonite or Fuller's earth for
      periods ranging from less than 15 years to more than 40 years developed
      dyspnea, in some cases accompanied by cough and sputum, and
      pneumoconiosis. The general characteristics of the pneumoconiosis of the
      above five workers, as revealed on autopsy, included emphysema, lesions,
      numerous firm black patches and nodules 1- 20 mm in diameter, dilated air
      sacs, adhesions, isolated cavities filled with "black sludge," and other
      evidence of physical deterioration. ...The accumulated dust amounted to
      128 mg/g of dry lung (analyzed by transmission electron microscopy). There
      was very little or no fibrosis of the type associated with silicosis.
      Microscopic examination of lung tissue revealed that the nodules were
      aggregates of fine brown pigment lying free in tissue spaces or contained
      in macrophages held in a fine reticulum.[WHO; Environ Health Criteria 231:
      Bentonite, Kaolin, and Selected Clay Minerals (2005). Available from, as
      of April 3, 2013: http://www.inchem.org/pages/ehc.html] **PEER REVIEWED** 

      /CASE REPORTS/ /Investigators/ demonstrate that exposure to bentonite dust
      containing 5-11% silica can lead to silicosis. Exposure to this bentonite
      dust for 10 years with no other known exposure to silica dust led to
      advanced silicosis in three workers and to death, apparently from
      silicosis, in one of these three. All showed radiological evidence of
      silicosis, and the presence of silica in the lungs was confirmed by biopsy
      in one case.[WHO; Environ Health Criteria 231: Bentonite, Kaolin, and
      Selected Clay Minerals (2005). Available from, as of April 3, 2013:
      http://www.inchem.org/pages/ehc.html] **PEER REVIEWED** 

      /CASE REPORTS/ ...A 20-year-old dental assistant who noted a foreign body
      in her right eye after using a drill to polish a patient's teeth with
      Prophypaste. Immediately she noticed decreased vision and photophobia.
      Several opaque deposits superficially embedded in her right cornea were
      removed within 2 h. There was no evidence of corneal perforation or
      iritis. A residual superficial corneal infiltrate was noted paracentrally.
      An anterior uveitis developed and was treated. One month after the injury,
      the cornea was edematous with a superficial, peripheral ringlike stromal
      infiltrate and a deep inferior stromal infiltrate. A retrocorneal abscess
      was present. There was no eyelid edema present. Culture results were
      negative. Anterior segment inflammation, progression of the corneal edema,
      and an enlarged ring abscess in the corneal stroma continued. There was
      complete loss of red reflex and iris detail. The diagnosis was infectious
      endophthalmitis and anterior chamber and vitreous aspirations were
      performed. No organisms were seen but a few PMN leukocytes were present in
      the aspirations. These authors undertook the toxicity studies in rabbits
      presented in the ocular animal toxicity section under Bentonite. They
      concluded that the similarity of the findings in animals after injection
      of Bentonite with the findings in this case report suggested that
      Bentonite was the responsible agent in the dental assistant's
      symptoms.[Cosmetic Ingredient Review; Final Report of the Cosmetic
      Ingredient Review Expert Panel; Final Report on the Safety Assessment of
      Aluminum Silicate, Calcium Silicate, Magnesium Aluminum Silicate,
      Magnesium Silicate, Magnesium Trisilicate, Sodium Magnesium Silicate,
      Zirconium Silicate, Attapulgite, Bentonite, Fuller's Earth, Hectorite,
      Kaolin, Lithium Magnesium Silicate, Lithium Magnesium Sodium Silicate,
      Montmorillonite, Pyrophyllite, and Zeolite; International Journal of
      Toxicology 22 (Suppl 1): 37-102 (2003)] **PEER REVIEWED** 

      /CASE REPORTS/ A 67-yr old man who had been employed in a bentonite
      milling plant in Wyoming for 10 yr underwent open lung biopsy to evaluate
      severe dyspnea with chest radiographic findings of circumscribed nodules.
      Chronic granulomatous inflammation consistent with silicosis was
      documented.[Rom, W.N. (ed.). Environmental and Occupational Medicine. 2nd
      ed. Boston, MA: Little, Brown and Company, 1992., p. 481] **PEER
      REVIEWED** 

      /CASE REPORTS/ ...A 3-year-old girl presented with a chief complaint of
      vomiting, constipation, lethargy, and weakness over several days. On
      initial evaluation, the child was mildly dehydrated and had a serum
      potassium of 0.9 mmol/L. Electrocardiographic findings were also
      consistent with hypokalemia. Upon further questioning, the parents
      reported that they had been administering a home remedy, containing
      colloidal bentonite, both orally and rectally as treatment for persistent
      constipation. The child received intravenous antibiotics, a normal saline
      bolus, and multiple boluses of potassium chloride, resulting in eventual
      normalization of her electrolyte abnormalities.  Ingestion of large
      quantities of clay substances, such as bentonite, can result in
      gastrointestinal binding of essential electrolytes and possible
      obstruction. Symptoms and laboratory values often resolve with replacement
      of electrolytes and cessation of bentonite intake. Although cases of oral
      ingestion of clay-like substances resulting in electrolyte abnormalities
      have been reported, there are no previously reported human cases of
      hypokalemia caused specifically by bentonite administration. This may be
      due to the unique rectal administration seen in this child, which has not
      previously been described.[Bennett A, Stryjewski G; Pediatr Emerg Care 22
      (7): 500-2 (2006)] **PEER REVIEWED** <a
      href="http://www.ncbi.nlm.nih.gov/pubmed/16871112?dopt=Abstract"
      target=new>PubMed Abstract 

      /GENOTOXICITY/ To study the genotoxicity induced by organic bentonite
      particles in vitro. Human B lymphoblast cells (HMy2.CIR) were exposed to
      organic bentonite particles at the doses of 0, 1.88, 3.75, 7.50 and 15.00
      ug/mL for 24, 48 and 72 hr, calcium sulfate (30 ug/mL) and SiO2 (30 and
      240 ug/mL) served as negative and positive controls, respectively. The
      genotoxicity of organic bentonite particles and soluble fraction was
      detected using comet assay and Cytokinesis-block micronucleus (CBMN)
      assay. The results of comet assay indicated that % tail DNA increased with
      the exposure doses and time in organic bentonite group, % tail DNA at the
      dose of 15.00 ug/mL for 24 hr, 48 hr and 72 hr in organic bentonite group
      were 3.20 +/- 0.19, 4.63 +/- 0.88 and 9.49 +/- 1.31 respectively which
      were significantly higher than those in calcium sulfate group (1.40 +/-
      0.11, 1.37 +/- 0.22 and 0.90 +/- 0.16) and those in 30 ug/mL SiO2 group
      (1.83 +/- 0.21, 1.41 +/- 0.27 and 2.48 +/- 0.25) (P   <  0.01). The
      results of CBMN assay showed that micronucleus frequencies (MNF) in
      organic bentonite group (except for 1.88 ug/mL for 24 hr) were
      significantly higher than those in 30 ug/mL calcium sulfate group (MNF for
      24, 48 and 72 hr were 1.33% +/- 0.58%, 1.33% +/- 1.15% and 1.33% +/-
      0.58%) and those in 30 ug/mL SiO2 group (2.00% +/-0.00%, 1.68% +/- 0.58%
      and 2.33% +/- 0.58%) (P   <  0.01). The results of two assays demonstrated
      that the soluble fraction of organic bentonite did not induce the
      genotoxicity. The organic bentonite dusts can induce the genotoxicity in
      vitro, which may be from the particle fraction.[Li XX et al; Zhonghua Lao
      Dong Wei Sheng Zhi Ye Bing Za Zhi. 28 (12): 914-7 (2010)] **PEER
      REVIEWED** <a
      href="http://www.ncbi.nlm.nih.gov/pubmed/21241602?dopt=Abstract"
      target=new>PubMed Abstract 

      /GENOTOXICITY/ In the present study, we investigated the genotoxic
      potential of bentonite particles (diameter   <  10 um) with an a-quartz
      content of up to 6% and different chemical modifications (alkaline,
      acidic, organic). Human lung fibroblasts (IMR90) were incubated for 36 hr,
      48 hr, or 72 hr with bentonite particles in concentrations ranging from 1
      to 15 ug/sq cm. Genotoxicity was assessed using the micronucleus (MN)
      assay and kinetochore analysis. The generation of reactive oxygen species
      (ROS) caused by bentonite particles via Fenton-like mechanisms was
      measured acellularly using electron spin resonance (ESR) technique and
      intracellularly by applying an iron chelator. The results show that
      bentonite-induced genotoxic effects in human lung fibroblasts are weak.
      The formation of micronuclei was only slightly increased after exposure of
      IMR90 cells to an acidic sample of bentonite dust with a quartz content of
      4-5% for 36 hr (15 ug/sq cm), 48 hr (5 ug/sq cm), and 72 hr (1 ug/sq cm),
      to an alkaline sample with a quartz content of 5% for 48 hr and 72 hr (15
      ug/sq cm), and to an acidic bentonite sample with 1% quartz for 72 hr (1
      ug/sq cm). Native (untreated) and organic activated bentonite particles
      did not show genotoxic effects in most of the experiments. Also, bentonite
      particles with a quartz content   <  1% were negative in the micronucleus
      assay. Generation of ROS measured by ESR was dependent on the content of
      transition metals in the sample but not on the quartz content or the
      chemical modification. Reduction of MN after addition of the iron chelator
      2,2'-dipyridyl showed that ROS formation also occurs intracellularly.
      Altogether, /the authors/ conclude that the genotoxic potential of
      bentonite particles is generally low but can be altered by the content of
      quartz and available transition metals.[Geh S et al; Inhal Toxicol.18 (6):
      405-12 (2006)] **PEER REVIEWED** <a
      href="http://www.ncbi.nlm.nih.gov/pubmed/16556580?dopt=Abstract"
      target=new>PubMed Abstract 

      /ALTERNATIVE and IN VITRO TESTS/ To assess the cytotoxicity of four clays
      containing an aluminum silicate-montmorillonite, bentonite, kaolinite and
      erionite-we used human umbilical vein endothelial, N1E-115 neuroblastoma,
      and ROC-1 oligodendroglial cells. Morphological examination, lactate
      dehydrogenase release and fatty acid release were used as indices of
      trauma. The clays were added in suspension to the cell cultures at
      concentrations of 0.1, 0.03 and 0.01 mg/mL of medium and the cells were
      incubated for 1, 6 and 24 hr. The clays did not lyse ROC-1 and N1E-115
      cells and did not cause a dose-dependent increase in fatty acid levels at
      24 hr. There were no significant increases in lactate dehydrogenase
      activity in N1E-115 neuroblastoma or ROC-1 oligodendroglial cells. In
      human umbilical vein endothelial cells, montmorillonite, kaolinite and
      bentonite caused a dose-dependent increase in fatty acids at 24 hr. All
      three clays caused cell lysis. /The authors/ postulate that the
      cytotoxicity of the clays containing an aluminum silicate towards
      endothelial cells may disrupt the blood-brain barrier in the affected
      areas, allowing the entry of the clay particle into the brain. Aluminum
      silicate clays caused a dose-dependent release of fatty acids in human
      umbilical vein endothelial cells. The clays also caused lysis of these
      cells. ROC-1 oligodendroglia and N1E-115 neuroblastoma cells were not
      lysed by the clays, suggesting that this is not a general
      phenomenon.[Murphy EJ et al; Neuroscience 55 (2): 597-605 (1993)] **PEER
      REVIEWED** <a
      href="http://www.ncbi.nlm.nih.gov/pubmed/8397348?dopt=Abstract"
      target=new>PubMed Abstract 

      /ALTERNATIVE and IN VITRO TESTS/ Considering the biological reactivity of
      pure quartz in lung cells, there is a strong interest to clarify the
      cellular effects of respirable siliceous dusts, like bentonites. In the
      present study, /the authors/ investigated the cellular uptake and the
      cytotoxic potential of bentonite particles (0  <  10 um) with an
      alpha-quartz content of up to 6% and different chemical modifications
      (activation: alkaline, acidic, organic) in human lung fibroblasts (IMR90).
      Additionally, the ability of the particles to induce apoptosis in
      IMR90-cells and the hemolytic activity was tested. All bentonite samples
      were tested for endotoxins with the in vitro-Pyrogen test and were found
      to be negative. Cellular uptake of particles by IMR90-cells was studied by
      transmission electron microscopy (TEM). Cytotoxicity was analyzed in
      IMR90-cells by determination of viable cells using flow cytometry and by
      measuring of the cell respiratory activity. Induced apoptotic cells were
      detected by AnnexinV/Propidiumiodide-staining and gel electrophoresis. Our
      results demonstrate that activated bentonite particles are better taken up
      by IMR90-cells than untreated (native) bentonite particles. Also,
      activated bentonite particles with a quartz content of 5-6% were more
      cytotoxic than untreated bentonites or bentonites with a quartz content
      lower than 4%. The bentonite samples induced necrotic as well as apoptotic
      cell death. In general, bentonites showed a high membrane-damaging
      potential shown as hemolytic activity in human erythrocytes. We conclude
      that cellular effects of bentonite particles in human lung cells are
      enhanced after chemical treatment of the particles. The cytotoxic
      potential of the different bentonites is primarily characterized by a
      strong lysis of the cell membrane.[Geh S et al; Arch Toxicol. 80 (2):
      98-106 (2006)] **PEER REVIEWED** <a
      href="http://www.ncbi.nlm.nih.gov/pubmed/16059726?dopt=Abstract"
      target=new>PubMed Abstract 

      /ALTERNATIVE and IN VITRO TESTS/ Cell suspensions were incubated with
      bentonite or montmorillonite for (where specified) 30 min to 24 hr, and
      the cells were tested for physical integrity or functional ability. Cell
      types included rat peritoneal macrophages, rabbit and rat alveolar
      macrophages, a macrophage-like cell line, other white cells, human and
      other erythrocytes, rodent neural cells, hamster tracheal epithelial
      cells, and human umbilical vein endothelial cells. The results usually
      indicated a high degree of cytotoxicity. Concentrations below 1.0 mg/mL of
      bentonite and montmorillonite particles less than 5 um in diameter caused
      lysis of human neutrophils, many types of erythrocytes, mouse embryo
      neuronal cells, and human umbilical vein endothelial cells. The velocity
      and degree of lysis of sheep erythrocytes were dose dependent. Using cow
      erythrocytes and montmorillonite, /investigators/ found that particles
      0.2-2.0 um in diameter were most active and that particles greater than
      2.0 um in diameter showed little or no haemolytic activity. The ability of
      low concentrations of these particles to lyse mammalian cells, although
      widespread, was not universal, since /investigators/ reported no lysis of
      neuroblastoma cells or oligodendroglial cells incubated in 0.1 mg
      montmorillonite or bentonite/mL for 18 or 24 hr.[IPCS Environmental Health
      Criteria 231, Bentonite, Kaolin and selected clay minerals. Available
      from, as of April 5, 2013:
      http://www.inchem.org/documents/ehc/ehc/ehc231.htm] **PEER REVIEWED** 

      /OTHER TOXICITY INFORMATION/ The use of bentonite in various branches of
      industry, and first of all, in foundry workshops, grows rapidly. The
      literature data on health injuries bybentonite dust are rather
      contradictory: due primarily, to the changeable mineralogical composition
      of the raw material from different deposits. That requires a specific
      hygienic assessment of each deposit in exploitation. The authors studied
      the mineral composition, quantitative ratio of the mineral components and
      morphology of the particles from the respirable fraction of aerosol in the
      extraction of Bulgarian bentonite. The microscopic mineralogical analysis
      in phase contrast, established a basic mass of clay minerals, confirmed by
      the X-ray structural analysis. The free silicic oxide is presented by
      low-temperature crystobalite and quartz, more rarely opal and chalcedony.
      Its quantity does not surpass 1-2%. The experimental studies on
      experimental animals confirmed fibrosis, degree I and II, according to
      Belt and King. The clinical studies on the workers established the
      presence of reticular changes in the lungs, type S and L, according to
      ILO-UC classification. The hygienic characteristic of the Bulgarian
      bentonite provided grounds for its broad application as a substitute for
      more dangerous raw materials, quartz sand in the foundries, in particular.
      Regardless of its advantages, bentonite is not harmless. The adherence to
      MAC for dustiness and periodic control of the quartz content in the raw
      material and aerosol in the working environment, are
      compulsory.[Mikha?lova-Docheva L et al; Probl Khig 11: 106-13 (1986)]
      **PEER REVIEWED** <a
      href="http://www.ncbi.nlm.nih.gov/pubmed/3823030?dopt=Abstract"
      target=new>PubMed Abstract 

      /OTHER TOXICITY INFORMATION/ In a sample of 32 workers exposed for varying
      periods to dust from processing, 14 showed radiological evidence of
      silicosis. These observations suggest that the beneficial effects
      /previously/ ascribed to bentonite in protecting rat lungs from silicosis
      may not be present in humans.[WHO; Environ Health Criteria 231: Bentonite,
      Kaolin, and Selected Clay Minerals (2005). Available from, as of April 3,
      2013: http://www.inchem.org/pages/ehc.html] **PEER REVIEWED** 

PROBABLE ROUTES OF HUMAN EXPOSURE:
      According to the 2006 TSCA Inventory Update Reporting data, the number of
      persons reasonably likely to be exposed in the industrial manufacturing,
      processing, and use of bentonite is 100 to 999; the data may be greatly
      underestimated(1).[(1) US EPA; Inventory Update Reporting (IUR).
      Non-confidential 2006 IUR Records by Chemical, including Manufacturing,
      Processing and Use Information. Washington, DC: U.S. Environmental
      Protection Agency. Available from, as of Mar 25, 2013:
      http://cfpub.epa.gov/iursearch/index.cfm] **PEER REVIEWED** 

      NIOSH (NOES Survey 1981-1983) has statistically estimated that 545,795
      workers (36,750 of these were female) were potentially exposed to
      bentonite in the US. Statistically, an estimated 1,732, 6,525 and workers
      were potentially exposed to Blackhills bentonite, Wyoming bentonite in the
      US; (none of these were female). An estimated that 11,850 workers (11,045
      of these were female) were potentially exposed to bentonite powder(1).
      Occupational exposure to bentonite may occur through inhalation of dust
      and dermal contact with this compound at workplaces where bentonite is
      produced or used. Use data indicate that the general population may be
      exposed to bentonite via ingestion of and dermal contact with consumer
      products containing bentonite(SRC).[(1) NIOSH; NOES. National Occupational
      Exposure Survey conducted from 1981-1983. Estimated numbers of employees
      potentially exposed to specific agents by 2-digit standard industrial
      classification (SIC). Available from, as of Mar 25, 2013:
      http://www.cdc.gov/noes/] **PEER REVIEWED** 

      Occupational exposure to bentonite dust (total and
      respirable)(1).Location/Date No. Observ/No. Facil Concn Range (mg/cu m)
      Avg/Range (mg/cu m) Fuller's Earth Plant, IL/1934 5/1 1-19 6 Bentonite
      Plants, WY/1950-1967 17/4 1-92 11-60 Older Iron Foundry, Germany/pre-1980
      6/1 0.08-12.3 6.6 Modern Iron Foundry, Germany/pre-1980 5/1 0.56-7.9 4.8
      Bentonite mines & plants, Bulgaria/pre-1981 220/? 1.6-1430.0 333
      Non-ferrous foundry/pre-1987 13/1 0.20-27.9 6.65 Mines & plants,
      USA/1992-1998 251/16 0.00-6.97 0.06-2.18 Mines & plants, Turkey/1996-1999
      24/11 2.6-11.2  Foundries, Turkey/1990-1998 207/70 0.05-33.9  [(1) IPCS;
      Environmental Health Criteria 231. Bentonite, Kaolin, and Selected Clay
      Minerals. Geneva, Switzerland: World Health Org, Internl Prog Chem Safety
      (2005)] **PEER REVIEWED** 

      ...effects of bentonite in workers in processing plant.../showed/ some
      injurious effects...in lungs...[Browning, E. Toxicity of Industrial
      Metals. 2nd ed. New York: Appleton-Century-Crofts, 1969., p. 9] **PEER
      REVIEWED** 

REPORTED FATAL DOSE:
      1. 1= PRACTICALLY NONTOXIC: PROBABLE ORAL LETHAL DOSE (HUMAN) ABOVE 15
      G/KG, MORE THAN 1 QT (2.2 LB) FOR 70 KG PERSON (150 LB).[Gosselin, R.E.,
      H.C. Hodge, R.P. Smith, and M.N. Gleason. Clinical Toxicology of
      Commercial Products. 4th ed. Baltimore: Williams and Wilkins, 1976., p.
      II-67] **PEER REVIEWED** 

EMERGENCY MEDICAL TREATMENT:

EMERGENCY MEDICAL TREATMENT:
      
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any responsibility or risk for your use of the Truven Health Analytics Inc.
products.<p>The following Overview, *** BENTONITE ***, is relevant for this HSDB
record chemical.
LIFE SUPPORT: 
o   This overview assumes that basic life support measures
       have been instituted.
CLINICAL EFFECTS: 
0.2.1 SUMMARY OF EXPOSURE
   0.2.1.1 ACUTE EXPOSURE
     A)  Bentonite clay is physiologically inert. Upon
         ingestion, bentonite will swell into a homogenous mass
         up to 12 times the volume of the dry powder which may
         produce intestinal obstruction.
   0.2.1.2 CHRONIC EXPOSURE
     A)  The powder may contain large amounts of free silica
         which can produce pneumoconiosis with chronic
         inhalation.
  0.2.4 HEENT
   0.2.4.1 ACUTE EXPOSURE
     A)  Direct eye exposure resulted in severe anterior segment
         uveitis and retrocorneal abscess in a dental assistant.
  0.2.6 RESPIRATORY
   0.2.6.1 ACUTE EXPOSURE
     A)  Chronic inhalation exposure to similar clays, such as
         Fuller's earth, has been shown to cause pneumoconiosis
         without pathological changes of silicosis. Symptoms
         usually appear after many years of exposure.
     B)  Bronchospasm was reported in up to 25 percent of
         bentonite-exposed workers in one processing plant.
  0.2.8 GASTROINTESTINAL
   0.2.8.1 ACUTE EXPOSURE
     A)  Bentonite has been used therapeutically as a bulk
         laxative, due to its ability to adsorb water and to
         swell into a homogenous mass. Ingestion without
         adequate liquids may result in intestinal obstruction.
  0.2.12 FLUID-ELECTROLYTE
   0.2.12.1 ACUTE EXPOSURE
     A)  Hypokalemia and microcytic iron-deficiency anemia has
         been described in patients chronically ingesting clay.
     B)  Hypokalemia was noted in a cat supposedly chronically
         ingesting bentonite from cat litter, although this
         etiology has been disputed.
  0.2.13 HEMATOLOGIC
   0.2.13.1 ACUTE EXPOSURE
     A)  Microcytic iron-deficiency anemia may occur following
         chronic ingestion.
  0.2.15 MUSCULOSKELETAL
   0.2.15.1 ACUTE EXPOSURE
     A)  Chronic ingestion has been reported to cause myositis.
     B)  A cat supposedly chronically ingesting bentonite from
         cat litter developed lethargy and muscle weakness,
         although this etiology has been disputed.
  0.2.20 REPRODUCTIVE HAZARDS
    A)  At the time of this review, no reproductive studies were
        found for bentonite in humans or experimental animals.
  0.2.21 CARCINOGENICITY
   0.2.21.1 IARC CATEGORY
     A)  IARC Carcinogenicity Ratings for CAS1302-78-9 (IARC
         Working Group on the Evaluation of Carcinogenic Risks
         to Humans, 2006; IARC Working Group on the Evaluation
         of Carcinogenic Risks to Humans, 2007; IARC Working
         Group on the Evaluation of Carcinogenic Risks to
         Humans, 2010; IARC Working Group on the Evaluation of
         Carcinogenic Risks to Humans, 2010a; IARC Working Group
         on the Evaluation of Carcinogenic Risks to Humans,
         2008; IARC, 2004):
      1)  Not Listed
  0.2.22 GENOTOXICITY
    A)  At the time of this review, no genetic studies were
        found for bentonite.
LABORATORY: 
A)  Laboratory measures are not usually useful. Monitor serum
       potassium levels in patients with significant exposure.
   B)  If respiratory tract irritation is present, monitor chest
       x-ray.
TREATMENT OVERVIEW: 
0.4.2 ORAL EXPOSURE
    A)  DILUTION: Immediately dilute with 4 to 8 ounces (120 to
        240 mL) of water or milk (not to exceed 4 ounces/120 mL
        in a child).
    B)  Encourage fluid intake. Monitor for evidence of
        constipation and intestinal obstruction.
  0.4.3 INHALATION EXPOSURE
    A)  ACUTE - Acute effects have not been described. Refer to
        the document on TALC for more information.
  0.4.4 EYE EXPOSURE
    A)  DECONTAMINATION: Irrigate exposed eyes with copious
        amounts of room temperature water for at least 15
        minutes. If irritation, pain, swelling, lacrimation, or
        photophobia persist, the patient should be seen in a
        health care facility.
  0.4.5 DERMAL EXPOSURE
    A)  OVERVIEW
     1)  DECONTAMINATION: Remove contaminated clothing and wash
         exposed area thoroughly with soap and water. A
         physician may need to examine the area if irritation or
         pain persists.
RANGE OF TOXICITY: 
A)  Acute poisoning is more related to water intake than to
       dose. In chronic exposure experimental animal studies,
       bentonite at 1% to 2% of the diet did not effect calcium
       or phosphorus metabolism, but larger amounts caused
       decreased growth, muscle weakness, and death with marked
       changes in both calcium and phosphorus metabolism.

ANTIDOTE AND EMERGENCY TREATMENT:
      If breathed in, move person into fresh air. If not breathing, give
      artificial respiration.[Sigma-Aldrich Material Safety Data Sheet for
      Nanoclay, hydrophilic bentonite. Available from, as of April 3, 2013:
      http://www.sigmaaldrich.com/catalog/product/aldrich/682659?lang=en&region=US]
      **PEER REVIEWED** 

ANIMAL TOXICITY STUDIES:

TOXICITY SUMMARY:
      IDENTIFICATION: Bentonite is a rock formed of highly colloidal and plastic
      clays composed mainly of montmorillonite and produced in situ
      devitrification of volcanic ash. It may contain feldspar, cristobalite and
      crystaline quartz. Major uses of bentonite include binding foundry sand in
      molds, absorbing grease, oil and animal wastes; palletizing taconite iron
      ore and improving the properties of drilling muds. It is used as an
      ingredient in ceramics, water proofing and sealing in civil engineering
      projects such as landfill sites and nuclear waste repositories, serving as
      a filter, stabilizer or extender in adhesives, paints, cosmetics and
      medicines. It is used as a bonding agent in animal feed, carrier for
      pesticides, clarifying wine and vegetable oil and purifying waste water.
      HUMAN EXPOSURE: In the view of widespread distribution of bentonite in
      nature and its use in various consumer products, general population
      exposure to low concentrations is ubiquitous. Occupational exposure to
      bentonite dust from mining, processing and user industries is a factor.
      ANIMAL STUDIES: Single intratracheal injection into rodents of bentonite
      and montmorillonite with low quartz content caused dose and particle side
      dependent effects, as well as transient local inflammation, which included
      edema and increased lung weight. Single intratracheal exposures of rats to
      bentonite caused storage foci in the lungs. After intratracheal exposure
      of rats to this material with high quartz content, fibrosis is noted. Mice
      maintained on diets containing bentonite displayed slightly reduced growth
      rates. Mice treated with higher doses showed minimal growth and fatty
      livers and fibrosis of the liver and benign hepatomas. Bentonite increased
      the susceptibility of mice to pulmonary infection. In vitro studies of the
      effects of bentonite on a variety of mammalian cell types indicated a high
      degree of cytotoxicity. Limited studies did not demonstrate developmental
      toxicity in rats after oral exposure to bentonite. No adequate studies are
      available on the carcinogenicity of bentonite.[[World Health
      Organization/International Programme on Chemical Safety; Environmental
      Heath Criteriia 231 Bentonite, Kaolin and Selected Clay Minerals pp. 1-5
      (2005)]] **PEER REVIEWED** 

NON-HUMAN TOXICITY EXCERPTS:
      /LABORATORY ANIMALS: Acute Exposure/ Ten (5M:5F) albino rats, 200 - 254 g,
      each received a single oral dose of the test article at a concentration of
      5 grams per kilogram bodyweight. Animals were observed for pharmacologic
      activity and drug toxicity 1, 3, 6, and 24 hours after treatment, and
      daily thereafter for a total of 14 days. Non-survivors and animals
      surviving the 14 day observation period were subjected to gross necropsy,
      with all findings noted. The test article was used as a 25 % gravimetric
      corn oil suspension. Dose Level:5 mg/kg Mortality: 0 % This test article
      is not toxic orally to rats under conditions of this test.[European
      Chemicals Bureau; IUCLID Dataset for Bentonite(1302-78-9), p.30 (2000
      CD-ROM edition). Available from, as of April 2, 2013:
      http://ecb.jrc.ec.europa.eu/esis/] **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ Ten (5M:5F) albino rats, 210 - 298 g,
      were exposed to the test article at an atmospheric concentration of 200
      milligrams per liter for 1 hour. Animals were observed for pharmacotoxic
      effects and mortality 1, 3, 6, and 24 hours after treatment, and daily
      thereafter for a total of 14 days. Non-survivors and animals sacrificed at
      the end of the 14 day observation period were subjected to gross necropsy,
      with all findings noted. The test article was used as received. Dose
      Level: 200 mg/L Mortality: 0 % The test article is not toxic to rats by
      inhalation under conditions of this test.[European Chemicals Bureau;
      IUCLID Dataset for Bentonite(1302-78-9), p.31 (2000 CD-ROM edition).
      Available from, as of April 2, 2013: http://ecb.jrc.ec.europa.eu/esis/]
      **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ Six (3M:3F) New Zealand white
      rabbits, 2.31- 3.19 kilograms, each received a single dermal application
      of the test article at a dose level of 2 grams per kilogram bodyweight.
      The skin of three (3J animals (2M:1F) was abraded; the remaining animals'
      skin remained intact. The test sites were occluded for 24 hours, at which
      time the occlusive wrap and any remaining test article were removed.
      Animals were observed for pharmacologic activity 1, 3, 6, and 24 hours
      after treatment, and daily thereafter for a total of 14 days.
      Non-survivors and animals surviving the 14 day observation period were
      subjected to gross necropsy, with all findings noted. The test article was
      moistened with saline. Dose Level: 2 g/kg. Mortality: 0 % This test
      article is not toxic dermally to rabbits under conditions of this
      test.[European Chemicals Bureau; IUCLID Dataset for Bentonite(1302-78-9),
      p.32 (2000 CD-ROM edition). Available from, as of April 2, 2013:
      http://ecb.jrc.ec.europa.eu/esis/] **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ Six (6) New Zealand white rabbits
      each received a single dermal application of 0.5 gram of the test article
      on two test sites, one abraded and one intact. The test sites were
      occluded for 24 hours, and were observed individually for erythema, edema,
      and other effects 24 and 72 hours after application. Mean scores from the
      24 and 72 hour readings were averaged to determine the primary irritation
      index. The test article was moistened with water prior to use. Primary
      Irritation Index: 0.25. The test article is not a primary dermal irritant
      to rabbits under conditions of this test.[European Chemicals Bureau;
      IUCLID Dataset for Bentonite(1302-78-9), p.35 (2000 CD-ROM edition).
      Available from, as of April 2, 2013: http://ecb.jrc.ec.europa.eu/esis/]
      **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ Six (6) New Zealand white rabbits,
      free from visible ocular defects, each received a single intraocular
      application of 0.1 gram of the test article in one eye. The contralateral
      eye, remaining untreated, served as a control. The eyes of all animals
      remained unwashed for 24 hours. Observations of corneal opacity, iritis,
      conjunctivitis, and other effects, were recorded 24, 48, and 72 hours
      after treatment, and at 4 and 7 days if irritation persisted. The test
      article was used as received. The test article is a mild ocular irritant
      to rabbits under conditions of this test.[European Chemicals Bureau;
      IUCLID Dataset for Bentonite(1302-78-9), p.36 (2000 CD-ROM edition).
      Available from, as of April 2, 2013: http://ecb.jrc.ec.europa.eu/esis/]
      **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ /Investigators/ gave subplantar
      injections of 0.05 mL of a 5% solution of Bentonite to male Wistar rats.
      The rats either received both hind paw injections at an interval of 24 hr
      or their left paw was injected with Bentonite and their right paw injected
      with 0.05 mL of a 10% solution of Kaolin. The injection was of Kaolin.
      Subcutaneous Bentonite granulomas were produced on the left side, both
      dorsally and ventrally. Simultaneously Kaolin granulomas were produced on
      the right side analogous to the Bentonite injection. Sodium salicylate and
      prednisone suppressed the Bentonite edema during the first 24 hr. The
      presence of mononuclear cells was confirmed.[Cosmetic Ingredient Review;
      Final Report of the Cosmetic Ingredient Review Expert Panel; Final Report
      on the Safety Assessment of Aluminum Silicate, Calcium Silicate, Magnesium
      Aluminum Silicate, Magnesium Silicate, Magnesium Trisilicate, Sodium
      Magnesium Silicate, Zirconium Silicate, Attapulgite, Bentonite, Fuller's
      Earth, Hectorite, Kaolin, Lithium Magnesium Silicate, Lithium Magnesium
      Sodium Silicate, Montmorillonite, Pyrophyllite, and Zeolite; International
      Journal of Toxicology 22 (Suppl 1): 37-102 (2003)] **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ /Investigators/ administered a single
      dose of 40 mg of Bentonite suspended in 1 mL of physiological saline
      containing 40,000 IU of crystalline penicillin intratracheally to male CFY
      rats. The Bentonite's composition consisted of 73% Montmorillonite, 18%
      cristobalite, 3% quartz, 3% feldspar, and 3% other minerals. Particle
      sizes were   < 2 um. The control group received 1 mL of physiological
      saline containing 40,000 IU of crystalline penicillin. Animals were killed
      12, 24, 48, or 72 hr or 90 days after exposure. Body and lung weight of
      the rats were measured. The right lung was fixed and sectioned for
      microscopic examination. The lipids and phospholipids were analyzed in the
      left lung. The body weights of the rats were moderately decreased and the
      lung weight increased 72 hr after Bentonite exposure. After 90 days, the
      lung weight was only slightly greater than that of the control animals.
      Upon microscopic examination at 12 hr, Bentonite exposure had resulted in
      a nonspecific inflammation of mostly neutrophils with perivascular edema,
      alveolitis, and incipient bronchopneumonia. A small number of macrophages
      and lymphocytes were detected. Dust particles were observed in the
      leukocytes and macrophages or extracellularly in the alveoli. After the
      24th hr, bronchopneumonia was present after coalescence of the
      inflammatory foci; the pneumonia then became necrotizing and desquamative.
      Necrotic neutrophilic leukocytes and eosinophil leukocytes were observed.
      The reticular network collapsed between the 48th and 72nd hr. Exposure
      after 90 days included dust storage foci filled with large foamy cells
      with pale cytoplasm. Closely packed cells with dark cytoplasm and nuclei
      were located at the periphery. After 12 and 24 hr, the amount of lipids
      and phospholipids in the lungs was not altered. However, between 48 and 72
      hr, the lipid and phospholipid content increase but distribution remained
      the same. After 90 days the value was the same as seen at 72 hr.[Cosmetic
      Ingredient Review; Final Report of the Cosmetic Ingredient Review Expert
      Panel; Final Report on the Safety Assessment of Aluminum Silicate, Calcium
      Silicate, Magnesium Aluminum Silicate, Magnesium Silicate, Magnesium
      Trisilicate, Sodium Magnesium Silicate, Zirconium Silicate, Attapulgite,
      Bentonite, Fuller's Earth, Hectorite, Kaolin, Lithium Magnesium Silicate,
      Lithium Magnesium Sodium Silicate, Montmorillonite, Pyrophyllite, and
      Zeolite; International Journal of Toxicology 22 (Suppl 1): 37-102 (2003)]
      **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ Preparations of Prophypaste,
      Bentonite, tragacanth, trypsin, and sterile water were injected either
      intralamellarly or directly into the anterior chamber of six adult New
      Zealand rabbits at concentrations ranging from 1 to 5 mg/mL. No
      significant reactions were recorded with sterile water, Prophypaste,
      tragacanth, or combinations of tragacanth and Bentonite. Bentonite caused
      severe iritis after injection into the anterior chamber, but no corneal or
      retrocorneal reaction was noted grossly or microscopically. In five of the
      eyes where Bentonite was injected intralamellarly, widespread corneal
      infiltrates and retrocorneal membranes were observed within 2 to 5 days.
      The sixth eye had no reaction, only 0.1 mL of 0.25 mg/mL was injected.
      Anterior chamber taps of the eyes showed viscous mucopurulent material.
      Microscopic sections showed pseodoeosinophils, retrocorneal membranes, and
      fibrovascular membranes in the anterior segment. Polarized light revealed
      highly birefringent particles were found at the injections sites, but not
      in the retrocorneal masses.[Cosmetic Ingredient Review; Final Report of
      the Cosmetic Ingredient Review Expert Panel; Final Report on the Safety
      Assessment of Aluminum Silicate, Calcium Silicate, Magnesium Aluminum
      Silicate, Magnesium Silicate, Magnesium Trisilicate, Sodium Magnesium
      Silicate, Zirconium Silicate, Attapulgite, Bentonite, Fuller's Earth,
      Hectorite, Kaolin, Lithium Magnesium Silicate, Lithium Magnesium Sodium
      Silicate, Montmorillonite, Pyrophyllite, and Zeolite; International
      Journal of Toxicology 22 (Suppl 1): 37-102 (2003)] **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ Intratracheal injection of moderate
      amounts (0.16-0.27 g/kg of body weight) of finely powdered (where
      specified, mean diameter   < 5 um) bentonite into rodents evoked responses
      indicative of cytotoxic effects, as well as rapid and/or long-lasting
      irritation of or damage to the lungs. Gross effects on the lungs of rats
      administered 0.19 g/kg of body weight included inflammation and edema
      within 12 hr, bronchopneumonia by day 1, and a doubling of wet weight by
      day 3, followed by a gradual decline to a value still significantly above
      the initial weight by day 90. The histology of the inflammation included
      large numbers of neutrophil leukocytes plus some macrophages and
      lymphocytes at 12 hr, mainly eosinophil and necrobiotic leukocytes by day
      1, and collapse of the reticular network by day 3. Some bentonite
      particles were held within the macrophages and leukocytes at day 3.
      Changes in gross morphology and histology were accompanied by changes in
      the chemistry of lung lavage fluid. These included elevated levels of
      phospholipid and acid phosphatase by day 3. The increase in phospholipid
      was not, however, accompanied by any change in the relative abundance of
      phospholipid fractions. Phospholipid was still somewhat elevated 3 months
      after exposure. ... Hydroxyproline was slightly elevated 3 months after
      exposure.[WHO; Environ Health Criteria 231: Bentonite, Kaolin, and
      Selected Clay Minerals (2005). Available from, as of April 3, 2013:
      http://www.inchem.org/pages/ehc.html] **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ The effects of smaller intratracheal
      doses of bentonite on rats are uncertain. /One study/ reported that 0.027
      g/kg of body weight had no effect on protein or lactate dehydrogenase
      (LDH) in lavage from the lung 15-60 days after dosage, whereas /a second
      study/, also using lavage from the lungs, noted a variety of effects
      indicating irritation and damage immediately following doses of 0.012 and
      0.0012 g/kg of body weight. These effects included large and rapid
      increases in soluble protein, LDH, and polymorphonuclear leukocytes, with
      peaks at day 1 or day 2 followed by a decline to somewhat above baseline
      by day 7. Alveolar macrophages were increased by day 7. The findings in
      these two studies need not be contradictory, since the observations of
      /the second study/ permit the possibility that elevated values for LDH and
      protein were present following dosage in the /first/ experiment, but
      declined back to baseline prior to their first sample on day 15.  The
      changes in gross morphology, white cell abundances, and biochemistry
      described above appear to form a generally coherent picture. Swelling and
      edema stem from changes at the cellular level. /Investigators/ found
      increased LDH and protein in the lavage-sensitive indicators of lung
      damage that preceded visible mechanical damage and impairment of gas
      exchange. Increased LDH was ascribed to damage to cell membranes and
      leakage from lung cells, whereas increased protein was ascribed to
      increased vascular permeability. The latter conclusion is supported by
      /previous/ analyses, which reported serum albumin as the major constituent
      of the recovered protein. The increases in polymorphonuclear leukocytes
      may be triggered by phagocytosis of bentonite particles by alveolar
      macrophages.[WHO; Environ Health Criteria 231: Bentonite, Kaolin, and
      Selected Clay Minerals (2005). Available from, as of April 3, 2013:
      http://www.inchem.org/pages/ehc.html] **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ Single intratracheal exposures of
      rats to bentonite produced storage foci in the lungs 3-12 months later;
      even 12 months after exposure, fibrosis had not progressed beyond
      Belt-King grade 1. Macroscopically, the foci were visible in fixed
      material as greyish-white masses up to the size of a "pin prick or a poppy
      seed" - i.e., approximately 1 mm. The structure of these storage foci was
      described in detail using slides stained with hematoxylin-eosin, Van
      Gieson's solution, and Foot's silver impregnation. /Investigators/
      reported that "The foci contained large cells with foamy protoplasm, and
      [with] nuclei often located at the edge of the cells. In the foam cells no
      lipids could be demonstrated by Sudan staining. PAS [para-aminosalicylic
      acid] reaction was intensely positive, showing that substances of
      carbohydrate nature are accumulated in the foci. In polarized light a
      great mass of intracellularly located doubly refractive fine grainy
      substance was to be seen. This characteristic alteration was to be
      observed in the lungs of the animals killed the 40th day after the
      application of the dust, and the microscopic findings in the tissues had
      not changed essentially up to the end of the experiment [365 days]. In the
      foci, sometimes a poorly developed reticular network of loose structure
      occurred too, but collagen fibers did not develop. The silver impregnated
      preparations showed in the area of the foci the precipitation of a
      greyish-black homogeneous substance between the fibers."[WHO; Environ
      Health Criteria 231: Bentonite, Kaolin, and Selected Clay Minerals (2005).
      Available from, as of April 3, 2013: http://www.inchem.org/pages/ehc.html]
      **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ In addition to directly damaging the
      lung, bentonite had a potential, even at low doses, for increasing
      susceptibility to pulmonary infection. /Investigators/ followed single
      intratracheal injections of 5, 0.5, or 0.05 mg/kg of body weight into mice
      with aerosolized Group C Streptococcus sp. The lowest dose did not
      significantly elevate mortality from Streptococcus infection over
      controls, whereas the highest dose produced 85% excess mortality and the
      intermediate dose 43% excess mortality over controls. Earlier studies
      demonstrated a close correlation between the effects on susceptibility to
      infection following dosing by sustained inhalation and by administering
      the same amount of test substance in a single intratracheal
      injection.[WHO; Environ Health Criteria 231: Bentonite, Kaolin, and
      Selected Clay Minerals (2005). Available from, as of April 3, 2013:
      http://www.inchem.org/pages/ehc.html] **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ In most experiments, bentonite also
      displayed local toxic effects after intra- or subdermal injection.
      Subdermal injection of 10 mg/kg of body weight as 5% bentonite gel into
      the plantar of rats produced pronounced edema within an hour. The swelling
      continued to enlarge for a week and then slowly regressed, but it was
      still evident 6 weeks after injection. The edema was accompanied by marked
      increases in macrophages and polymorphonuclear leukocytes, which peaked at
      30 hr. The leukocytes declined back to the baseline after 4 weeks, whereas
      the macrophages were still elevated at 6 weeks.[WHO; Environ Health
      Criteria 231: Bentonite, Kaolin, and Selected Clay Minerals (2005).
      Available from, as of April 3, 2013: http://www.inchem.org/pages/ehc.html]
      **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ The granulomatous inflammation
      resulting from a moderate intradermal injection of relatively coarse
      (diameter 79-90 um) bentonite into the skin of guinea-pigs was
      /investigated/ both visually and with light and electron microscopy. The
      injection induced a chronic inflammatory response with ulceration and
      maximum induration at 7-10 days. By day 2, there was vascular dilation and
      some infiltration of monocytes and polymorphonuclear leukocytes. The
      macrophage infiltration rapidly increased in density and by the
      termination of observations, day 30, had become mainly multinuclear cells,
      had phagocytized most of the bentonite particles, and had evolved into a
      loose, disorganized mass. This mass was walled off from adjoining tissues
      by active fibrosis, which also subdivided the cells into clumps.[WHO;
      Environ Health Criteria 231: Bentonite, Kaolin, and Selected Clay Minerals
      (2005). Available from, as of April 3, 2013:
      http://www.inchem.org/pages/ehc.html] **PEER REVIEWED** 

      /LABORATORY ANIMALS: Acute Exposure/ Bentonite, a silicate, induces a
      classical non-immunological foreign body reaction when injected
      intradermally into guinea pigs. The cellular response consists of a mass
      of macrophages and large macrophage polykaryons, surrounded and
      infiltrated by an extensive fibrous reaction. The bentonite granuloma
      shows no signs of intercellular organization of the reacting cells. Study
      of its ultrastructure suggests a low turnover lesion with a stable,
      long-lived cell population. The bentonite granuloma is contrasted with the
      tuberculous, immunologically mediated epithelioid cell granuloma produced
      in sensitized guinea pigs.[Browett PJet al; J Pathol 130 (1): 57-64
      (1980)] **PEER REVIEWED** <a
      href="http://www.ncbi.nlm.nih.gov/pubmed/6991658?dopt=Abstract"
      target=new>PubMed Abstract 

      /LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ During 33-day addn
      to fodder of chickens at 2 & 6% & during 90-day introduction into
      concentrations 1, 3 & 5%, activated bentonite did not provoke any
      changes in behavior, overall state & in the clinical biochemical &
      electrolytic composition of blood, but caused growth suppression.[DRUMEV D
      ET AL; VET MED NAUKI 17 (3): 84 (1980)] **PEER REVIEWED** 

      /LABORATORY ANIMALS: Chronic Exposure or Carcinogenicity/ There are
      limited data on the effects of multiple exposures of experimental animals
      to montmorillonite or bentonite. Mice maintained on diets containing 10%
      or 25% bentonite but otherwise adequate to support normal growth displayed
      slightly reduced growth rates, whereas mice maintained on a similar diet
      with 50% bentonite showed minimal growth and developed fatty livers and
      eventually fibrosis of the liver and benign hepatomas.[WHO; Environ Health
      Criteria 231: Bentonite, Kaolin, and Selected Clay Minerals (2005).
      Available from, as of April 3, 2013: http://www.inchem.org/pages/ehc.html]
      **PEER REVIEWED** 

      /ALTERNATIVE and IN VITRO TESTS/ In vitro studies of the effects of
      bentonite on a variety of mammalian cell types usually indicated a high
      degree of cytotoxicity. Concentrations below 1.0 mg/mL of bentonite and
      montmorillonite particles less than 5 um in diameter caused membrane
      damage and even cell lysis, as well as functional changes in several types
      of cells. The velocity and degree of lysis of sheep erythrocytes were dose
      dependent.[WHO; Environ Health Criteria 231: Bentonite, Kaolin, and
      Selected Clay Minerals (2005). Available from, as of April 3, 2013:
      http://www.inchem.org/pages/ehc.html] **PEER REVIEWED** 

      /ALTERNATIVE and IN VITRO TESTS/ Cell suspensions were incubated with
      bentonite or montmorillonite for (where specified) 30 min to 24 hr, and
      the cells were tested for physical integrity or functional ability. Cell
      types included rat peritoneal macrophages, rabbit and rat alveolar
      macrophages, a macrophage-like cell line, other white cells, human and
      other erythrocytes, rodent neural cells, hamster tracheal epithelial
      cells, and human umbilical vein endothelial cells. The results usually
      indicated a high degree of cytotoxicity. Concentrations below 1.0 mg/mL of
      bentonite and montmorillonite particles less than 5 um in diameter caused
      lysis of human neutrophils, many types of erythrocytes, mouse embryo
      neuronal cells, and human umbilical vein endothelial cells. The velocity
      and degree of lysis of sheep erythrocytes were dose dependent. Using cow
      erythrocytes and montmorillonite, /investigators/ found that particles
      0.2-2.0 um in diameter were most active and that particles greater than
      2.0 um in diameter showed little or no haemolytic activity. The ability of
      low concentrations of these particles to lyse mammalian cells, although
      widespread, was not universal, since /investigators/ reported no lysis of
      neuroblastoma cells or oligodendroglial cells incubated in 0.1 mg
      montmorillonite or bentonite/mL for 18 or 24 hr.[IPCS Environmental Health
      Criteria 231, Bentonite, Kaolin and selected clay minerals. Available
      from, as of April 5, 2013:
      http://www.inchem.org/documents/ehc/ehc/ehc231.htm] **PEER REVIEWED** 

      /VETERINARY CASE REPORTS/ A 2 1/2-y-old spayed female cat was presented
      for lethargy and weakness. The cat was hypokalemic (3.1 m Eq K/L) and
      severely anemic (60% PVC, 1.3 g hemoglobin/dL). The cat was known to
      ingest bentonite-containing cat litter. It recovered with treatment of iv
      fluids, electrolytes and whole blood transfusion and was discharged. Two
      months later the cat was presented again with signs similar to those seen
      previously. This occurred 1 mo after the owner resumed the use of
      bentonite-containing cat litter. The signs were remarkably similar to
      those reported in humans from the chronic ingestion of bentonite clays.
      Bentonite toxicosis is suggested by the coexistence of hypokalemia
      hypochromic anemia in cats presented with lethargy and muscle
      weakness.[Hornfeldt CS et al; Vet Hum Toxicol 38 (5): 365-6 (1996)] **PEER
      REVIEWED** <a
      href="http://www.ncbi.nlm.nih.gov/pubmed/8888544?dopt=Abstract"
      target=new>PubMed Abstract 

NON-HUMAN TOXICITY VALUES:
      LD50 Rat intravenous 35 mg/kg[Lewis, R.J. Sr. (ed) Sax's Dangerous
      Properties of Industrial Materials. 11th Edition. Wiley-Interscience,
      Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 351] **PEER REVIEWED** 

ECOTOXICITY VALUES:
      LC50; Species: Oncorhynchus mykiss (Rainbow Trout) weight 1 (0.3-2.9) g;
      Conditions: freshwater, static, 10.5 deg C, pH 8.2, hardness 340 mg/L
      CaCO3; Concentration: 19000000 ug/L for 96 hr /formulation/[Sprague JB,
      Logan WJ; Environ Pollut 19 (4): 269-281 (1979) as cited in the ECOTOX
      database. Available from, as of February 11, 2013:
      http://cfpub.epa.gov/ecotox/quick_query.htm] **PEER REVIEWED** 

METABOLISM/PHARMACOKINETICS:

MECHANISM OF ACTION:
      The mechanism by which bentonite increases susceptibility is unknown.
      /Investigators/ however, postulated that enzyme inhibition by bentonite
      may be a factor, based on their in vitro observation that a low
      concentration of bentonite can totally suppress the activity of human
      leukocyte elastase, an enzyme important in the destruction of
      microorganisms phagocytized by neutrophils.[WHO; Environ Health Criteria
      231: Bentonite, Kaolin, and Selected Clay Minerals (2005). Available from,
      as of April 3, 2013: http://www.inchem.org/pages/ehc.html] **PEER
      REVIEWED** 

INTERACTIONS:
      Numerous studies have established that aflatoxin is a potent developmental
      toxin in animals. Previous research has demonstrated that a phyllosilicate
      clay, hydrated sodium calcium aluminosilicate (HSCAS or Novasil), tightly
      binds and immobilizes aflatoxins in the gastrointestinal tract of animals
      and markedly reduces the bioavailability and toxicity of aflatoxin. Our
      objective in this study was to utilize the pregnant rat as an in vivo
      model to compare the potential of hydrated sodium calcium aluminosilicate
      and bentonite to prevent the developmental toxicity of aflatoxin.
      Aluminosilicates (HSCAS) and bentonite were added to the diet at a level
      of 0.5% (w/w) and fed to the pregnant rat throughout pregnancy (ie days
      0-20). Test animals were fed an aflatoxin-contaminated diet (2.5 mg kg(-1)
      diet) with or without sorbents during gestation days 6-15. Evaluations of
      toxicity were performed on day 20. These included maternal (mortality,
      body weights, feed intake and litter weights), developmental (embryonic
      resorptions and fetal body weights) and biochemical (ALT, AST and AP)
      evaluations. Sorbents alone were not toxic and aflatoxin alone resulted in
      significant maternal and developmental toxicity. Animals treated with
      phyllosilicate (plus aflatoxin) were comparable to controls following
      evaluations for resorptions, live fetuses and fetal body weights, as well
      as biochemical parameters. While bentonite plus aflatoxin resulted in
      significant reduction in fetal body weight, none of the fetuses from
      hydrated sodium calcium aluminosilicate or bentonite plus
      aflatoxin-treated groups had any gross, internal soft tissue or major
      skeletal malformations.[Abdel-Wahhab MA et al; J Appl Toxicol 19 (3):
      199-204 (1999)] **PEER REVIEWED** <a
      href="http://www.ncbi.nlm.nih.gov/pubmed/10362271?dopt=Abstract"
      target=new>PubMed Abstract 

      Molasses, sodium bentonite (montmorillonite clay) and zeolite (crushed
      clinoptilolite rock) were examined as supplement ingredients to improve
      the safety margin of urea supplementation in a series of seven
      experiments. These experiments were designed to provide an understanding
      of the relationship between urea intake and the influence of the above
      ingredients on rumen pH and total ammonia concentrations. Rumen fistulated
      Merino ewes of 35-40 kg live weight were administered various amounts of
      urea with and without supplement mixes. Rumen parameters were measured at
      0, 0.5, 1.0, 1.5, 2.5, 5.0 and 24 h after treatment administration. Acetic
      acid and sucrose were also tested together with molasses for comparative
      effects on rumen parameters. In the last experiment, blood pH and total
      plasma ammonia were also determined. Free ammonia values of rumen liquor
      were calculated for experiments 2 to 7. In four experiments, molasses at
      50, 100 and/or 150 g mixed with urea significantly reduced the normal
      rapid rise in ruminal pH, total and free ammonia values compared with urea
      (10 g) only treatments. In two experiments, associated presence or absence
      of clinical toxicity at various quantities of urea (8 to 25 g) with and
      without active ingredients confirmed the positive effect of molasses in
      preventing toxicity at : 0.44 g urea/kg liveweight. The addition of
      molasses reduced the increase in ruminal pH by up to 0.5 pH units and
      absolute values were consistently below pH 7.0. Sucrose (100 g) and acetic
      acid (800 ml of 1 M) had the same and greater effect, respectively,
      compared with molasses (150 g) when added with urea (10 g) on ruminal pH
      and total and free ammonia changes over five hours post treatment. The
      partly hydrated urea/bentonite mix (approx 1:1 bentonite:water ratio) was
      associated with a delay in the increases in ruminal pH and free ammonia
      concentrations. Bentonite mixes, in either fully hydrated or fully
      dehydrated states, and zeolite mixes resulted in no significant effects.
      With reference to previous reports, the results support the positive role
      of a stable acid pH in the rumen for ensuring safe urea
      supplementation.[Stephenson R GA et al; Aust J Agric Res 43 (2): 301-14
      (1992)] **PEER REVIEWED** 

      ...Ingestion of large quantities of clay substances, such as bentonite,
      can result in gastrointestinal binding of essential electrolytes and
      possible obstruction. ...[Bennett A, Stryjewski G; Pediatr Emerg Care 22
      (7): 500-2 (2006)] **PEER REVIEWED** <a
      href="http://www.ncbi.nlm.nih.gov/pubmed/16871112?dopt=Abstract"
      target=new>PubMed Abstract 

      /Investigators/ gave subplantar injections of 0.05 mL of a 5% solution of
      Bentonite to male Wistar rats. The rats either received both hind paw
      injections at an interval of 24 hr or their left paw was injected with
      Bentonite and their right paw injected with 0.05 mL of a 10% solution of
      Kaolin. The injection was of Kaolin. Subcutaneous Bentonite granulomas
      were produced on the left side, both dorsally and ventrally.
      Simultaneously Kaolin granulomas were produced on the right side analogous
      to the Bentonite injection. Sodium salicylate and prednisone suppressed
      the Bentonite edema during the first 24 hr. The presence of mononuclear
      cells was confirmed.[Cosmetic Ingredient Review; Final Report of the
      Cosmetic Ingredient Review Expert Panel; Final Report on the Safety
      Assessment of Aluminum Silicate, Calcium Silicate, Magnesium Aluminum
      Silicate, Magnesium Silicate, Magnesium Trisilicate, Sodium Magnesium
      Silicate, Zirconium Silicate, Attapulgite, Bentonite, Fuller's Earth,
      Hectorite, Kaolin, Lithium Magnesium Silicate, Lithium Magnesium Sodium
      Silicate, Montmorillonite, Pyrophyllite, and Zeolite; International
      Journal of Toxicology 22 (Suppl 1): 37-102 (2003)] **PEER REVIEWED** 

      /Investigators/ administered a single dose of 40 mg of Bentonite suspended
      in 1 mL of physiological saline containing 40,000 IU of crystalline
      penicillin intratracheally to male CFY rats. The Bentonite's composition
      consisted of 73% Montmorillonite, 18% cristobalite, 3% quartz, 3%
      feldspar, and 3% other minerals. Particle sizes were   < 2 um. The control
      group received 1 mL of physiological saline containing 40,000 IU of
      crystalline penicillin. Animals were killed 12, 24, 48, or 72 hr or 90
      days after exposure. Body and lung weight of the rats were measured. The
      right lung was fixed and sectioned for microscopic examination. The lipids
      and phospholipids were analyzed in the left lung. The body weights of the
      rats were moderately decreased and the lung weight increased 72 hr after
      Bentonite exposure. After 90 days, the lung weight was only slightly
      greater than that of the control animals. Upon microscopic examination at
      12 hr, Bentonite exposure had resulted in a nonspecific inflammation of
      mostly neutrophils with perivascular edema, alveolitis, and incipient
      bronchopneumonia. A small number of macrophages and lymphocytes were
      detected. Dust particles were observed in the leukocytes and macrophages
      or extracellularly in the alveoli. After the 24th hr, bronchopneumonia was
      present after coalescence of the inflammatory foci; the pneumonia then
      became necrotizing and desquamative. Necrotic neutrophilic leukocytes and
      eosinophil leukocytes were observed. The reticular network collapsed
      between the 48th and 72nd hr. Exposure after 90 days included dust storage
      foci filled with large foamy cells with pale cytoplasm. Closely packed
      cells with dark cytoplasm and nuclei were located at the periphery. After
      12 and 24 hr, the amount of lipids and phospholipids in the lungs was not
      altered. However, between 48 and 72 hr, the lipid and phospholipid content
      increase but distribution remained the same. After 90 days the value was
      the same as seen at 72 hr.[Cosmetic Ingredient Review; Final Report of the
      Cosmetic Ingredient Review Expert Panel; Final Report on the Safety
      Assessment of Aluminum Silicate, Calcium Silicate, Magnesium Aluminum
      Silicate, Magnesium Silicate, Magnesium Trisilicate, Sodium Magnesium
      Silicate, Zirconium Silicate, Attapulgite, Bentonite, Fuller's Earth,
      Hectorite, Kaolin, Lithium Magnesium Silicate, Lithium Magnesium Sodium
      Silicate, Montmorillonite, Pyrophyllite, and Zeolite; International
      Journal of Toxicology 22 (Suppl 1): 37-102 (2003)] **PEER REVIEWED** 

PHARMACOLOGY:

THERAPEUTIC USES:
      Ther (VET): The efficacy of locally produced bentonite was evaluated with
      respect to ameliorating the adverse effects of aflatoxins (AF) in piglets
      fed AF contaminated diets. Forty eight piglets were randomly assigned to
      one of four treatments: 1) 0 g of bentonite and 0 ug AF/kg feed (control);
      2) 4 g of bentonite plus 200 ug AF/kg feed (AF + Bento 4); 3) 5 g of
      bentonite plus 200 ug AF/kg feed (AF + Bento 5) and 4) 0 g of bentonite
      plus 200 ug AF/kg feed (AFA). Piglets in the AFA treatment had lower
      overall average daily weight gain (ADG), feed conversion efficiency,
      albumin (ALB) and total protein (TP) compared to the control diet, while
      mean serum leukocyte and enzyme activities (glutamic-oxalacetic
      transaminase (GOT), glutamic-pyruvic transaminase (GPT), gamma
      glutamyltransferase (GGT), alkaline phosphatase (ALP) and lactic
      dehydrogenase (LDH)) were significant increased. The inclusion of
      bentonite at 0.4% or 0.5% in the AF contaminated diet restored the lower
      performance, feed efficiency and abnormal blood profiles of the piglets
      given AF and no differences between 0.4 and 0.5% inclusion of bentonite.
      The findings in the present study provide critically needed confirmation
      that bentonite has the ability to reduce the adverse effects of AF.[Thieu
      NQ et al; Trop Anim Health Prod 40 (8): 649-56 (2008)] **PEER REVIEWED**
      <a href="http://www.ncbi.nlm.nih.gov/pubmed/18975130?dopt=Abstract"
      target=new>PubMed Abstract 

      Ther (VET): Bentonite was compared with activated charcoal as therapy for
      lantana poisoning in calves dosed 5 d previously with leaf material of the
      common pink-edged red taxon of Lantana camara. Both therapies were given
      by stomach tube as a single dose at 5 g/kg. Five of 6 calves in each of
      the groups given bentonite and activated charcoal recovered while 5 of 6
      calves in the control group died. Calves given bentonite took 3 d longer
      on average to recover fully than those given activated charcoal but the
      effects of the 2 therapies on plasma total bilirubin concentrations were
      statistically indistinguishable. Bentonite was judged to have promise as a
      cheap alternative to activated charcoal for therapy of lantana poisoning
      of cattle.[McKenzie RA; Aust Vet J 68 (4); 146-8 (1991)] **PEER REVIEWED**
      
      Immediate administration of an absorbent after ingestion is likely to
      improve the outcome of a paraquat ingestion. Bentonite (75% suspension)
      & fuller's earth (30% suspension) in an adult dose of 100 to 150 g
      each, are thought to be the most effective. /Paraquat and Diquat
      Herbicides/[Rom, W.N. (ed.). Environmental and Occupational Medicine. 2nd
      ed. Boston, MA: Little, Brown and Company, 1992., p. 896] **PEER
      REVIEWED** 

INTERACTIONS:
      Numerous studies have established that aflatoxin is a potent developmental
      toxin in animals. Previous research has demonstrated that a phyllosilicate
      clay, hydrated sodium calcium aluminosilicate (HSCAS or Novasil), tightly
      binds and immobilizes aflatoxins in the gastrointestinal tract of animals
      and markedly reduces the bioavailability and toxicity of aflatoxin. Our
      objective in this study was to utilize the pregnant rat as an in vivo
      model to compare the potential of hydrated sodium calcium aluminosilicate
      and bentonite to prevent the developmental toxicity of aflatoxin.
      Aluminosilicates (HSCAS) and bentonite were added to the diet at a level
      of 0.5% (w/w) and fed to the pregnant rat throughout pregnancy (ie days
      0-20). Test animals were fed an aflatoxin-contaminated diet (2.5 mg kg(-1)
      diet) with or without sorbents during gestation days 6-15. Evaluations of
      toxicity were performed on day 20. These included maternal (mortality,
      body weights, feed intake and litter weights), developmental (embryonic
      resorptions and fetal body weights) and biochemical (ALT, AST and AP)
      evaluations. Sorbents alone were not toxic and aflatoxin alone resulted in
      significant maternal and developmental toxicity. Animals treated with
      phyllosilicate (plus aflatoxin) were comparable to controls following
      evaluations for resorptions, live fetuses and fetal body weights, as well
      as biochemical parameters. While bentonite plus aflatoxin resulted in
      significant reduction in fetal body weight, none of the fetuses from
      hydrated sodium calcium aluminosilicate or bentonite plus
      aflatoxin-treated groups had any gross, internal soft tissue or major
      skeletal malformations.[Abdel-Wahhab MA et al; J Appl Toxicol 19 (3):
      199-204 (1999)] **PEER REVIEWED** <a
      href="http://www.ncbi.nlm.nih.gov/pubmed/10362271?dopt=Abstract"
      target=new>PubMed Abstract 

      Molasses, sodium bentonite (montmorillonite clay) and zeolite (crushed
      clinoptilolite rock) were examined as supplement ingredients to improve
      the safety margin of urea supplementation in a series of seven
      experiments. These experiments were designed to provide an understanding
      of the relationship between urea intake and the influence of the above
      ingredients on rumen pH and total ammonia concentrations. Rumen fistulated
      Merino ewes of 35-40 kg live weight were administered various amounts of
      urea with and without supplement mixes. Rumen parameters were measured at
      0, 0.5, 1.0, 1.5, 2.5, 5.0 and 24 h after treatment administration. Acetic
      acid and sucrose were also tested together with molasses for comparative
      effects on rumen parameters. In the last experiment, blood pH and total
      plasma ammonia were also determined. Free ammonia values of rumen liquor
      were calculated for experiments 2 to 7. In four experiments, molasses at
      50, 100 and/or 150 g mixed with urea significantly reduced the normal
      rapid rise in ruminal pH, total and free ammonia values compared with urea
      (10 g) only treatments. In two experiments, associated presence or absence
      of clinical toxicity at various quantities of urea (8 to 25 g) with and
      without active ingredients confirmed the positive effect of molasses in
      preventing toxicity at : 0.44 g urea/kg liveweight. The addition of
      molasses reduced the increase in ruminal pH by up to 0.5 pH units and
      absolute values were consistently below pH 7.0. Sucrose (100 g) and acetic
      acid (800 ml of 1 M) had the same and greater effect, respectively,
      compared with molasses (150 g) when added with urea (10 g) on ruminal pH
      and total and free ammonia changes over five hours post treatment. The
      partly hydrated urea/bentonite mix (approx 1:1 bentonite:water ratio) was
      associated with a delay in the increases in ruminal pH and free ammonia
      concentrations. Bentonite mixes, in either fully hydrated or fully
      dehydrated states, and zeolite mixes resulted in no significant effects.
      With reference to previous reports, the results support the positive role
      of a stable acid pH in the rumen for ensuring safe urea
      supplementation.[Stephenson R GA et al; Aust J Agric Res 43 (2): 301-14
      (1992)] **PEER REVIEWED** 

      ...Ingestion of large quantities of clay substances, such as bentonite,
      can result in gastrointestinal binding of essential electrolytes and
      possible obstruction. ...[Bennett A, Stryjewski G; Pediatr Emerg Care 22
      (7): 500-2 (2006)] **PEER REVIEWED** <a
      href="http://www.ncbi.nlm.nih.gov/pubmed/16871112?dopt=Abstract"
      target=new>PubMed Abstract 

      /Investigators/ gave subplantar injections of 0.05 mL of a 5% solution of
      Bentonite to male Wistar rats. The rats either received both hind paw
      injections at an interval of 24 hr or their left paw was injected with
      Bentonite and their right paw injected with 0.05 mL of a 10% solution of
      Kaolin. The injection was of Kaolin. Subcutaneous Bentonite granulomas
      were produced on the left side, both dorsally and ventrally.
      Simultaneously Kaolin granulomas were produced on the right side analogous
      to the Bentonite injection. Sodium salicylate and prednisone suppressed
      the Bentonite edema during the first 24 hr. The presence of mononuclear
      cells was confirmed.[Cosmetic Ingredient Review; Final Report of the
      Cosmetic Ingredient Review Expert Panel; Final Report on the Safety
      Assessment of Aluminum Silicate, Calcium Silicate, Magnesium Aluminum
      Silicate, Magnesium Silicate, Magnesium Trisilicate, Sodium Magnesium
      Silicate, Zirconium Silicate, Attapulgite, Bentonite, Fuller's Earth,
      Hectorite, Kaolin, Lithium Magnesium Silicate, Lithium Magnesium Sodium
      Silicate, Montmorillonite, Pyrophyllite, and Zeolite; International
      Journal of Toxicology 22 (Suppl 1): 37-102 (2003)] **PEER REVIEWED** 

      /Investigators/ administered a single dose of 40 mg of Bentonite suspended
      in 1 mL of physiological saline containing 40,000 IU of crystalline
      penicillin intratracheally to male CFY rats. The Bentonite's composition
      consisted of 73% Montmorillonite, 18% cristobalite, 3% quartz, 3%
      feldspar, and 3% other minerals. Particle sizes were   < 2 um. The control
      group received 1 mL of physiological saline containing 40,000 IU of
      crystalline penicillin. Animals were killed 12, 24, 48, or 72 hr or 90
      days after exposure. Body and lung weight of the rats were measured. The
      right lung was fixed and sectioned for microscopic examination. The lipids
      and phospholipids were analyzed in the left lung. The body weights of the
      rats were moderately decreased and the lung weight increased 72 hr after
      Bentonite exposure. After 90 days, the lung weight was only slightly
      greater than that of the control animals. Upon microscopic examination at
      12 hr, Bentonite exposure had resulted in a nonspecific inflammation of
      mostly neutrophils with perivascular edema, alveolitis, and incipient
      bronchopneumonia. A small number of macrophages and lymphocytes were
      detected. Dust particles were observed in the leukocytes and macrophages
      or extracellularly in the alveoli. After the 24th hr, bronchopneumonia was
      present after coalescence of the inflammatory foci; the pneumonia then
      became necrotizing and desquamative. Necrotic neutrophilic leukocytes and
      eosinophil leukocytes were observed. The reticular network collapsed
      between the 48th and 72nd hr. Exposure after 90 days included dust storage
      foci filled with large foamy cells with pale cytoplasm. Closely packed
      cells with dark cytoplasm and nuclei were located at the periphery. After
      12 and 24 hr, the amount of lipids and phospholipids in the lungs was not
      altered. However, between 48 and 72 hr, the lipid and phospholipid content
      increase but distribution remained the same. After 90 days the value was
      the same as seen at 72 hr.[Cosmetic Ingredient Review; Final Report of the
      Cosmetic Ingredient Review Expert Panel; Final Report on the Safety
      Assessment of Aluminum Silicate, Calcium Silicate, Magnesium Aluminum
      Silicate, Magnesium Silicate, Magnesium Trisilicate, Sodium Magnesium
      Silicate, Zirconium Silicate, Attapulgite, Bentonite, Fuller's Earth,
      Hectorite, Kaolin, Lithium Magnesium Silicate, Lithium Magnesium Sodium
      Silicate, Montmorillonite, Pyrophyllite, and Zeolite; International
      Journal of Toxicology 22 (Suppl 1): 37-102 (2003)] **PEER REVIEWED** 

REPORTED FATAL DOSE:
      1. 1= PRACTICALLY NONTOXIC: PROBABLE ORAL LETHAL DOSE (HUMAN) ABOVE 15
      G/KG, MORE THAN 1 QT (2.2 LB) FOR 70 KG PERSON (150 LB).[Gosselin, R.E.,
      H.C. Hodge, R.P. Smith, and M.N. Gleason. Clinical Toxicology of
      Commercial Products. 4th ed. Baltimore: Williams and Wilkins, 1976., p.
      II-67] **PEER REVIEWED** 

ENVIRONMENTAL FATE & EXPOSURE:

ENVIRONMENTAL FATE/EXPOSURE SUMMARY:
      Bentonite's production and use in domestic products, cat litter,
      construction materials, ceramics, pharmaceuticals, beer and wine
      production and cosmetics may result in its release to the environment
      through various waste streams. Its use in drilling muds, in agricultural
      practice as a carrier and an animal feed binder will result in its direct
      release to the environment. Bentonite is a colloidal native hydrated
      aluminum silicate (clay) found in midwest of USA and in Canada.
      Occupational exposure to bentonite may occur through inhalation of dust
      and dermal contact with this compound at workplaces where bentonite is
      produced or used. Use data indicate that the general population may be
      exposed to bentonite via ingestion of and dermal contact with consumer
      products containing bentonite. (SRC) **PEER REVIEWED** 

PROBABLE ROUTES OF HUMAN EXPOSURE:
      According to the 2006 TSCA Inventory Update Reporting data, the number of
      persons reasonably likely to be exposed in the industrial manufacturing,
      processing, and use of bentonite is 100 to 999; the data may be greatly
      underestimated(1).[(1) US EPA; Inventory Update Reporting (IUR).
      Non-confidential 2006 IUR Records by Chemical, including Manufacturing,
      Processing and Use Information. Washington, DC: U.S. Environmental
      Protection Agency. Available from, as of Mar 25, 2013:
      http://cfpub.epa.gov/iursearch/index.cfm] **PEER REVIEWED** 

      NIOSH (NOES Survey 1981-1983) has statistically estimated that 545,795
      workers (36,750 of these were female) were potentially exposed to
      bentonite in the US. Statistically, an estimated 1,732, 6,525 and workers
      were potentially exposed to Blackhills bentonite, Wyoming bentonite in the
      US; (none of these were female). An estimated that 11,850 workers (11,045
      of these were female) were potentially exposed to bentonite powder(1).
      Occupational exposure to bentonite may occur through inhalation of dust
      and dermal contact with this compound at workplaces where bentonite is
      produced or used. Use data indicate that the general population may be
      exposed to bentonite via ingestion of and dermal contact with consumer
      products containing bentonite(SRC).[(1) NIOSH; NOES. National Occupational
      Exposure Survey conducted from 1981-1983. Estimated numbers of employees
      potentially exposed to specific agents by 2-digit standard industrial
      classification (SIC). Available from, as of Mar 25, 2013:
      http://www.cdc.gov/noes/] **PEER REVIEWED** 

      Occupational exposure to bentonite dust (total and
      respirable)(1).Location/Date No. Observ/No. Facil Concn Range (mg/cu m)
      Avg/Range (mg/cu m) Fuller's Earth Plant, IL/1934 5/1 1-19 6 Bentonite
      Plants, WY/1950-1967 17/4 1-92 11-60 Older Iron Foundry, Germany/pre-1980
      6/1 0.08-12.3 6.6 Modern Iron Foundry, Germany/pre-1980 5/1 0.56-7.9 4.8
      Bentonite mines & plants, Bulgaria/pre-1981 220/? 1.6-1430.0 333
      Non-ferrous foundry/pre-1987 13/1 0.20-27.9 6.65 Mines & plants,
      USA/1992-1998 251/16 0.00-6.97 0.06-2.18 Mines & plants, Turkey/1996-1999
      24/11 2.6-11.2  Foundries, Turkey/1990-1998 207/70 0.05-33.9  [(1) IPCS;
      Environmental Health Criteria 231. Bentonite, Kaolin, and Selected Clay
      Minerals. Geneva, Switzerland: World Health Org, Internl Prog Chem Safety
      (2005)] **PEER REVIEWED** 

      ...effects of bentonite in workers in processing plant.../showed/ some
      injurious effects...in lungs...[Browning, E. Toxicity of Industrial
      Metals. 2nd ed. New York: Appleton-Century-Crofts, 1969., p. 9] **PEER
      REVIEWED** 

NATURAL POLLUTION SOURCES:
      Clay of montmorillonite type, derived primarily from alteration of
      volcanic ash. Two distinct types of bentonite are (1) Wyoming and South
      Dakota deposits referred to as sodium montmorillonite having high gelling,
      swelling, and viscosity properties and (2) Mississippi bentonite referred
      to as calcium montmorillonite with little or no swelling capacity. /PRC:
      See CAS/RN 61029-13-8 & 1318-93-0/[Meister, R.T., Sine, C. (eds) Crop
      Protection Handbook Volume 92, Willoughby, OH, 2006., p. D 44] **PEER
      REVIEWED** 

      Colloidal native hydrated aluminum silicate (clay) found in midwest of USA
      and in Canada. Consists principally of montmorillonite,
      Al2O3.4SiO2.H2O.[O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of
      Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ:  Merck and Co.,
      Inc., 2006., p. 175] **PEER REVIEWED** 

      Wyoming; Mississippi; Texas; Canada; Italy; the former U.S.S.R.[Lewis,
      R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th  Edition. John Wiley
      & Sons, Inc. New York, NY 2007., p. 132] **PEER REVIEWED** 

      The largest and highest quality sodium bentonite deposits in the world are
      located in South Dakota, Wyoming, and Montana ... The Clay Spur bentonite
      bed extends west from Belle Fourche, SD, and then north into Alberta,
      Canada.[Murray HH; Ullmann's Encyclopedia of Industrial Chemistry. 7th ed.
      (1999-2012). New York, NY: John Wiley & Sons; Clays. Online Posting
      Date: 15 Dec 2006] **PEER REVIEWED** 

      Southern or subbentonites occur in Texas and Mississippi.[Murray HH;
      Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2012). New
      York, NY: John Wiley & Sons; Clays. Online Posting Date: 15 Dec 2006]
      **PEER REVIEWED** 

      Texas calcium bentonites are found in a belt paralleling the present gulf
      coast in Cretaceous and Tertiary sediments.[Murray HH; Ullmann's
      Encyclopedia of Industrial Chemistry. 7th ed. (1999-2012). New York, NY:
      John Wiley & Sons; Clays. Online Posting Date: 15 Dec 2006] **PEER
      REVIEWED** 

      Other calcium bentonites are produced in the United States in Arizona,
      Alabama, and Nevada.[Murray HH; Ullmann's Encyclopedia of Industrial
      Chemistry. 7th ed. (1999-2012). New York, NY: John Wiley & Sons;
      Clays. Online Posting Date: 15 Dec 2006] **PEER REVIEWED** 

      Bentonite deposits are also found in England, Germany, Argentina, Greece,
      Italy, Hungary, Italy, India, Japan, and the Republic of Georgia.[Murray
      HH; Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2012).
      New York, NY: John Wiley & Sons; Clays. Online Posting Date: 15 Dec
      2006] **PEER REVIEWED** 

ARTIFICIAL POLLUTION SOURCES:
      Bentonite's production and use in domestic products, cat litter,
      construction materials, ceramics, pharmaceuticals, beer and wine
      production and cosmetics(1) may result in its release to the environment
      through various waste streams(SRC). Its use in drilling muds, in
      agricultural practice as a carrier and an animal feed binder(1) will
      result in its direct release to the environment(SRC).[(1) Murray HH;
      Kirk-Othmer Encyclopedia of Chemical Technology. (1999-2012). New York,
      NY: John Wiley & Sons; Clays, Uses. Online Posting Date: 20 Dec 2002]
      **PEER REVIEWED** 

ENVIRONMENTAL BIODEGRADATION:
      Biodegradation of bentonite appears to be minimal, if it occurs at
      all(1).[(1) IPCS; Environmental Health Criteria 231. Bentonite, Kaolin,
      and Selected Clay Minerals. Geneva, Switzerland: World Health Org, Internl
      Prog Chem Safety (2005)] **PEER REVIEWED** 

ENVIRONMENTAL ABIOTIC DEGRADATION:
      Abiotic degradation of bentonite proceeds on a geological time
      scale(1).[(1) IPCS; Environmental Health Criteria 231. Bentonite, Kaolin,
      and Selected Clay Minerals. Geneva, Switzerland: World Health Org, Internl
      Prog Chem Safety (2005)] **PEER REVIEWED** 

ENVIRONMENTAL STANDARDS & REGULATIONS:

FIFRA REQUIREMENTS:
      Residues of bentonite are exempted from the requirement of a tolerance
      when used in accordance with good agricultural practice as inert (or
      occasionally active) ingredients in pesticide formulations applied to
      growing crops or to raw agricultural commodities after harvest. Use: solid
      diluent, carrier.[40 CFR 180.910 (USEPA); U.S. National Archives and
      Records Administration's Electronic Code of Federal Regulations. Available
      from, as of March 28, 2013: http://www.ecfr.gov/cgi-bin/ECFR?page=browse]
      **PEER REVIEWED** 

FDA REQUIREMENTS:
      Bentonite is an indirect food additive for use only as a component of
      adhesives.[21 CFR 175.105 (USEPA); U.S. National Archives and Records
      Administration's Electronic Code of Federal Regulations. Available from,
      as of March 27, 2013: http://www.ecfr.gov/cgi-bin/ECFR?page=browse] **PEER
      REVIEWED** 

      Substance added directly to human food affirmed as generally recognized as
      safe (GRAS).[21 CFR 184.1155 (USFDA); U.S. National Archives and Records
      Administration's Electronic Code of Federal Regulations. Available from,
      as of March 28, 2013: http://www.ecfr.gov/cgi-bin/ECFR?page=browse] **PEER
      REVIEWED** 

      Bentonite used as a general purpose food additive in animal drugs, feeds,
      and related products is generally recognized as safe when used in
      accordance with good manufacturing or feeding practice.[21 CFR 582.1155
      (USFDA); U.S. National Archives and Records Administration's Electronic
      Code of Federal Regulations. Available from, as of March 28, 2013:
      http://www.ecfr.gov/cgi-bin/ECFR?page=browse] **PEER REVIEWED** 

ALLOWABLE TOLERANCES:
      Residues of bentonite are exempted from the requirement of a tolerance
      when used in accordance with good agricultural practice as inert (or
      occasionally active) ingredients in pesticide formulations applied to
      growing crops or to raw agricultural commodities after harvest. Use: solid
      diluent, carrier.[40 CFR 180.910 (USEPA); U.S. National Archives and
      Records Administration's Electronic Code of Federal Regulations. Available
      from, as of March 28, 2013: http://www.ecfr.gov/cgi-bin/ECFR?page=browse]
      **PEER REVIEWED** 

CHEMICAL/PHYSICAL PROPERTIES:

MOLECULAR FORMULA:
      UVCB **PEER REVIEWED** 

MOLECULAR WEIGHT:
      .. a rock or clay base industrial material and is, therefore, a mixture of
      minerals. No molecular formula can be given.[IPCS; Environmental Health
      Criteria 231. Bentonite, Kaolin, and Selected Clay Minerals. Geneva,
      Switzerland: World Health Org, Internl Prog Chem Safety (2005)] **PEER
      REVIEWED** 

COLOR/FORM:
      A clay containing appreciable amounts of the clay mineral montmorillonite;
      light yellow or green, cream, pink, gray to black solid[Lewis, R.J. Sr.
      (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition.
      Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. V2: 351]
      **PEER REVIEWED** 

      The color in the massive condition varies from yellowish-white to almost
      black. The powder is cream colored to pale brown.[O'Neil, M.J. (ed.). The
      Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals.
      Whitehouse Station, NJ:  Merck and Co., Inc., 2006., p. 175] **PEER
      REVIEWED** 

      Light to cream-colored impalpable powder[Lewis, R.J. Sr.; Hawley's
      Condensed Chemical Dictionary 15th  Edition. John Wiley & Sons, Inc.
      New York, NY 2007., p. 132] **PEER REVIEWED** 

      The Clay Spur benonite usually ranges from 0.5 to 2 meters thick ...
      generally light yellowish green on the outcrop, becoming bluish green away
      from the outcrop.[Murray HH; Ullmann's Encyclopedia of Industrial
      Chemistry. 7th ed. (1999-2012). New York, NY: John Wiley & Sons;
      Clays. Online Posting Date: 15 Dec 2006] **PEER REVIEWED** 

      Southern or subbentonites are waxy and vary from blue when fresh to yellow
      when weathered.[Murray HH; Ullmann's Encyclopedia of Industrial Chemistry.
      7th ed. (1999-2012). New York, NY: John Wiley & Sons; Clays. Online
      Posting Date: 15 Dec 2006] **PEER REVIEWED** 

      Tertiary bentonite ranges from white to gray to yellow[Murray HH;
      Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2012). New
      York, NY: John Wiley & Sons; Clays. Online Posting Date: 15 Dec 2006]
      **PEER REVIEWED** 

      Texas calcium bentonites range from 0.5 to 3 meters thick and varies from
      yellow to green to dark brown.[Murray HH; Ullmann's Encyclopedia of
      Industrial Chemistry. 7th ed. (1999-2012). New York, NY: John Wiley &
      Sons; Clays. Online Posting Date: 15 Dec 2006] **PEER REVIEWED** 

      Cheto Arizona bentonite is white to light gray.[Murray HH; Ullmann's
      Encyclopedia of Industrial Chemistry. 7th ed. (1999-2012). New York, NY:
      John Wiley & Sons; Clays. Online Posting Date: 15 Dec 2006] **PEER
      REVIEWED** 

ODOR:
      Odorless[Osol, A. and J.E. Hoover, et al. (eds.). Remington's
      Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing
      Co., 1975., p. 334] **PEER REVIEWED** 

TASTE:
      Tasteless[Osol, A. and J.E. Hoover, et al. (eds.). Remington's
      Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing
      Co., 1975., p. 334] **PEER REVIEWED** 

PH:
      In the presence of water, it forms translucent suspension with pH of
      around 9[Osol, A. and J.E. Hoover, et al. (eds.). Remington's
      Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing
      Co., 1975., p. 334] **PEER REVIEWED** 

SOLUBILITIES:
      Insoluble in water and common organic solvents[Lewis, R.J. Sr. (ed) Sax's
      Dangerous Properties of Industrial Materials. 11th Edition.
      Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. V2: 351]
      **PEER REVIEWED** 

OTHER CHEMICAL/PHYSICAL PROPERTIES:
      Resists high temperatures & may be sterilized by heat[Browning, E.
      Toxicity of Industrial Metals. 2nd ed. New York: Appleton-Century-Crofts,
      1969., p. 3] **PEER REVIEWED** 

      Lamellar aluminum silicate, each lattice layer is sheet of hydrated
      alumina sandwiched between 2 silica sheets[Osol, A. and J.E. Hoover, et
      al. (eds.). Remington's Pharmaceutical Sciences. 15th ed. Easton,
      Pennsylvania: Mack Publishing Co., 1975., p. 309] **PEER REVIEWED** 

      Very fine powder free from grit, nearly white but may be pale buff or
      cream color; insoluble in water or acids; odorless with slightly earthy
      taste; it does not swell in organic solvents /Bentonite USP/[Osol, A. and
      J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th ed.
      Easton, Pennsylvania: Mack Publishing Co., 1975., p. 1243] **PEER
      REVIEWED** 

      Feels greasy and soap-like ... has a high cation exchange capacity[IPCS;
      Environmental Health Criteria 231. Bentonite, Kaolin, and Selected Clay
      Minerals. Geneva, Switzerland: World Health Org, Internl Prog Chem Safety
      (2005)] **PEER REVIEWED** 

      Interstitial water held in the clay mineral lattice is an additional major
      factor controlling the plastic, bonding, compaction, suspension and other
      properties of montmorillonite-group clay minerals[IPCS; Environmental
      Health Criteria 231. Bentonite, Kaolin, and Selected Clay Minerals.
      Geneva, Switzerland: World Health Org, Internl Prog Chem Safety (2005)]
      **PEER REVIEWED** 

      The property of forming gels is very much increased by addition of small
      amt of alkaline substances such as magnesium oxide.[O'Neil, M.J. (ed.).
      The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals.
      Whitehouse Station, NJ:  Merck and Co., Inc., 2006., p. 175] **PEER
      REVIEWED** 

      It has the property of forming highly viscous suspensions or gels with not
      less than ten times its weight of water.[O'Neil, M.J. (ed.). The Merck
      Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse
      Station, NJ:  Merck and Co., Inc., 2006., p. 175] **PEER REVIEWED** 

      Forms colloidal suspension in water with strongly thixotropic properties.
      There are two varieties: (1) sodium bentonite (Wyoming or western), has
      high swelling capacity in water, and (2) calcium bentonite (southern),
      with negligible swelling capacity.[Lewis, R.J. Sr.; Hawley's Condensed
      Chemical Dictionary 15th  Edition. John Wiley & Sons, Inc. New York,
      NY 2007., p. 132] **PEER REVIEWED** 

      The high-swelling Wyoming or sodium bentonites contain ca 30% moisture
      when delivered to the plant. The Southern or calcium bentonites have ca
      25% moisture. The processed bentonite generally contains only 7-8%
      moisture, although because bentonite is hygroscopic, it may contain
      considerably more moisture when used.[Gerhartz, W. (exec ed.). Ullmann's
      Encyclopedia of Industrial Chemistry. 5th ed.Vol A1: Deerfield Beach, FL:
      VCH Publishers, 1985 to Present., p. VA7: 124 (1986)] **PEER REVIEWED** 

      Bentonites in which sodium montmorillonites are the major mineral
      constituent have a high swelling capacity.[Murray HH; Ullmann's
      Encyclopedia of Industrial Chemistry. 7th ed. (1999-2012). New York, NY:
      John Wiley & Sons; Clays. Online Posting Date: 15 Dec 2006] **PEER
      REVIEWED** 

      Bentonites in which calcium montmorillonites are the major mineral
      constituent commonly have a low swelling capacity. The clays are commonly
      referred to as Southern or subbentonites.[Murray HH; Ullmann's
      Encyclopedia of Industrial Chemistry. 7th ed. (1999-2012). New York, NY:
      John Wiley & Sons; Clays. Online Posting Date: 15 Dec 2006] **PEER
      REVIEWED** 

CHEMICAL SAFETY & HANDLING:

FIRE POTENTIAL:
      Not combustible.[International Program on Chemical Safety/Commission of
      the European Union; International Chemical Safety Card on Bentonite
      (1302-78-9) (May 6, 2010). Available from, as of April 1, 2013:
      http://www.inchem.org/pages/icsc.html] **PEER REVIEWED** 

FIRE FIGHTING PROCEDURES:
      Use water spray, alcohol-resistant foam, dry chemical or carbon
      dioxide.[Sigma-Aldrich Material Safety Data Sheet for Nanoclay,
      hydrophilic bentonite. Available from, as of April 3, 2013:
      http://www.sigmaaldrich.com/catalog/product/aldrich/682659?lang=en&region=US]
      **PEER REVIEWED** 

      In case of fire in the surroundings; all extinguishing agents
      allowed.[International Program on Chemical Safety/Commission of the
      European Union; International Chemical Safety Card on Bentonite
      (1302-78-9) (May 6, 2010). Available from, as of April 1, 2013:
      http://www.inchem.org/pages/icsc.html] **PEER REVIEWED** 

HAZARDOUS REACTIVITIES & INCOMPATIBILITIES:
      Bentonite particles are negatively charged and flocculation occurs when
      electrolytes or positively charged suspensions are added. Bentonite is
      thus said to be incompatible with strong electrolytes...[Rowe, R.C.,
      Sheskey, P.J., Quinn, M.E.; (Eds.), Handbook of  Pharmaceutical Excipients
      6th edition Pharmaceutical Press,  London, England 2009, p. 54] **PEER
      REVIEWED** 

      Incompatibilities: acids and acid salts decrease the water-absorbing power
      and thus cause a breakdown of the magma.[Troy, D.B. (Ed); Remmington The
      Science and Practice of Pharmacy. 21 st Edition. Lippincott Williams &
      Williams, Philadelphia, PA 2005, p. 1073] **PEER REVIEWED** 

HAZARDOUS DECOMPOSITION:
      Hazardous decomposition products formed under fire conditions. - Aluminum
      oxide, silicon oxides[Sigma-Aldrich Material Safety Data Sheet for
      Nanoclay, hydrophilic bentonite. Available from, as of April 3, 2013:
      http://www.sigmaaldrich.com/catalog/product/aldrich/682659?lang=en&region=US]
      **PEER REVIEWED** 

PROTECTIVE EQUIPMENT & CLOTHING:
      Wear self-contained breathing apparatus for fire-fighting if
      necessary.[Sigma-Aldrich Material Safety Data Sheet for Nanoclay,
      hydrophilic bentonite. Available from, as of April 3, 2013:
      http://www.sigmaaldrich.com/catalog/product/aldrich/682659?lang=en&region=US]
      **PEER REVIEWED** 

      Provide appropriate exhaust ventilation at places where dust is
      formed.[Sigma-Aldrich Material Safety Data Sheet for Nanoclay, hydrophilic
      bentonite. Available from, as of April 3, 2013:
      http://www.sigmaaldrich.com/catalog/product/aldrich/682659?lang=en&region=US]
      **PEER REVIEWED** 

      Avoid inhalation of dust. Use local exhaust or breathing
      protection.[International Program on Chemical Safety/Commission of the
      European Union; International Chemical Safety Card on Bentonite
      (1302-78-9) (May 6, 2010). Available from, as of April 1, 2013:
      http://www.inchem.org/pages/icsc.html] **PEER REVIEWED** 

      Protective gloves. Wear safety goggles or eye protection in combination
      with breathing protection.[International Program on Chemical
      Safety/Commission of the European Union; International Chemical Safety
      Card on Bentonite (1302-78-9) (May 6, 2010). Available from, as of April
      1, 2013: http://www.inchem.org/pages/icsc.html] **PEER REVIEWED** 

STABILITY/SHELF LIFE:
      Suspensions are most stable at a pH above 7.[Troy, D.B. (Ed); Remmington
      The Science and Practice of Pharmacy. 21 st Edition. Lippincott Williams
      & Williams, Philadelphia, PA 2005, p. 1073] **PEER REVIEWED** 

STORAGE CONDITIONS:
      Keep container tightly closed in a dry and well-ventilated
      place.[Sigma-Aldrich Material Safety Data Sheet for Nanoclay, hydrophilic
      bentonite. Available from, as of April 3, 2013:
      http://www.sigmaaldrich.com/catalog/product/aldrich/682659?lang=en&region=US]
      **PEER REVIEWED** 

      Bentonite should be stored in an airtight contaner in a cool, dry
      place.[Rowe, R.C., Sheskey, P.J., Quinn, M.E.; (Eds.), Handbook of 
      Pharmaceutical Excipients 6th edition Pharmaceutical Press,  London,
      England 2009, p. 54] **PEER REVIEWED** 

      Bentonite is hygroscopic, and sorption of atmospheric water should be
      avoided.[Rowe, R.C., Sheskey, P.J., Quinn, M.E.; (Eds.), Handbook of 
      Pharmaceutical Excipients 6th edition Pharmaceutical Press,  London,
      England 2009, p. 54] **PEER REVIEWED** 

CLEANUP METHODS:
      Sweep up and shovel. Keep in suitable, closed containers for
      disposal.[Sigma-Aldrich Material Safety Data Sheet for Nanoclay,
      hydrophilic bentonite. Available from, as of April 3, 2013:
      http://www.sigmaaldrich.com/catalog/product/aldrich/682659?lang=en&region=US]
      **PEER REVIEWED** 

      Personal protection: particulate filter respirator adapted to the airborne
      concentration of the substance. Sweep spilled substance into covered
      containers. If appropriate, moisten first to prevent dusting. Wash away
      remainder with plenty of water.[International Program on Chemical
      Safety/Commission of the European Union; International Chemical Safety
      Card on Bentonite (1302-78-9) (May 6, 2010). Available from, as of April
      1, 2013: http://www.inchem.org/pages/icsc.html] **PEER REVIEWED** 

DISPOSAL METHODS:
      SRP: At the time of review, criteria for land treatment or burial
      (sanitary landfill) disposal practices are subject to significant
      revision. Prior to implementing land disposal of waste residue (including
      waste sludge), consult with environmental regulatory agencies for guidance
      on acceptable disposal practices. **PEER REVIEWED** 

OCCUPATIONAL EXPOSURE STANDARDS:

MANUFACTURING/USE INFORMATION:

MAJOR USES:
      As of Fuller's earth; as emulsifier for oils; as a base for plasters.
      Pharmaceutical aid (suspending agent).[O'Neil, M.J. (ed.). The Merck Index
      - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse
      Station, NJ:  Merck and Co., Inc., 2006., p. 175] **PEER REVIEWED** 

      Granular carrier; powder suspension agent[Farm Chemicals Handbook 2000.
      Willoughby, Ohio: Meister 2000., p. C 50] **PEER REVIEWED** 

      Drilling mud; foundry binders; iron ore pelletizing; cat litter; sealants;
      animal feed binders; paint; agricultural carriers; nanoclays; industrial
      oil absorbants; bleaching clays; catalysts; detergents; ceramics;
      cosmetics; dessicants; crayons; medical formulations; beer and wine
      clarification; suspension aids; de-inking on paper; tape joint compounds;
      emulsion stabilizers; slurry trench excavation; adhesives;
      pharmaceuticals; organoclays /Smectites/[Murray HH; Kirk-Othmer
      Encyclopedia of Chemical Technology. (1999-2012). New York, NY: John Wiley
      & Sons; Clays, Uses. Online Posting Date: 20 Dec 2002] **PEER
      REVIEWED** 

      Oil-well drilling fluids; cement slurries for oil-well casings; bonding
      agent in foundry sands and pelletizing of iron ores; sealant for canal
      walls; thickener in lubricating greases and fireproofing compositions;
      cosmetics; decolorizing agent; filler in ceramics, refractories, paper
      coatings; asphalt modifier; polishes and abrasives; food additive;
      catalyst support[Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary
      15th  Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 132]
      **PEER REVIEWED** 

      Drying agent in fertilizer impregnations /Flo-Fre/[Lewis, R.J. Sr.;
      Hawley's Condensed Chemical Dictionary 15th  Edition. John Wiley &
      Sons, Inc. New York, NY 2007., p. 570] **PEER REVIEWED** 

      Bentonite functions as an absorbent, bulking agent, emulsion stabilizer,
      opacifying agent, suspending agent-nonsurfactant, and viscosity-increasing
      agent-aqueous in cosmetic formulations.[Cosmetic Ingredient Review; Final
      Report of the Cosmetic Ingredient Review Expert Panel; Final Report on the
      Safety Assessment of Aluminum Silicate, Calcium Silicate, Magnesium
      Aluminum Silicate, Magnesium Silicate, Magnesium Trisilicate, Sodium
      Magnesium Silicate, Zirconium Silicate, Attapulgite, Bentonite, Fuller's
      Earth, Hectorite, Kaolin, Lithium Magnesium Silicate, Lithium Magnesium
      Sodium Silicate, Montmorillonite, Pyrophyllite, and Zeolite; International
      Journal of Toxicology 22 (Suppl 1): 37-102 (2003)] **PEER REVIEWED** 

      Bentonite is listed as being used in foundry sand bonding, bleaching clay
      in oil refining and decolorizers, filtering agents, water impedance,
      animal feed, pharmaceuticals, paint, plasticity increasers, and iron-ore
      pelletizing. Another source reported Bentonite as being used as an
      adsorbent, emulsion stabilizer, and suspending agent. Bentonite is
      categorized by the National Formulary as a suspending and/or
      viscosity-increasing agent.[Cosmetic Ingredient Review; Final Report of
      the Cosmetic Ingredient Review Expert Panel; Final Report on the Safety
      Assessment of Aluminum Silicate, Calcium Silicate, Magnesium Aluminum
      Silicate, Magnesium Silicate, Magnesium Trisilicate, Sodium Magnesium
      Silicate, Zirconium Silicate, Attapulgite, Bentonite, Fuller's Earth,
      Hectorite, Kaolin, Lithium Magnesium Silicate, Lithium Magnesium Sodium
      Silicate, Montmorillonite, Pyrophyllite, and Zeolite; International
      Journal of Toxicology 22 (Suppl 1): 37-102 (2003)] **PEER REVIEWED** 

      The leading uses of nonswelling bentonite were in foundry sand and water
      treatment and filtering.[USGS; Minerals Yearbook 2010 Database on Clay and
      Shale. Available from, as of Mar 23, 2013:
      http://minerals.usgs.gov/minerals/pubs/commodity/clays/myb1-2010-clays.pdf]
      **PEER REVIEWED** 

      For smaller markets, swelling bentonite accounted for more than 95% of the
      bentonite sold for adhesives; animal feed; clarifying and decolorizing
      animal, mineral, and vegetable oils and greases; cosmetics, medical, and
      pharmaceutical; fertilizers; miscellaneous ceramics; miscellaneous fillers
      and extenders; oil and grease absorbents; paint; and plastics. Swelling
      bentonite accounted for less than 50% of sales for water treatment and
      filtering. Nonswelling bentonite accounted for most sales for chemical
      manufacturing and fertilizer and pesticide carriers.[USGS; Minerals
      Yearbook 2010 Database on Clay and Shale. Available from, as of Mar 23,
      2013:
      http://minerals.usgs.gov/minerals/pubs/commodity/clays/myb1-2010-clays.pdf]
      **PEER REVIEWED** 

      One of 17-clay-like ingredients that are based on silicates ... used in a
      wide variety of product types, including bath products, makeup and skin
      care products ... acts as an absorbent, bulking agent, emulsion
      stabilizer, opacifying agent, suspending agent - nonsurfactant and
      viscosity increasing agent (aqueous)[Personal Care Products Council;
      CosmeticsINFO.org. Washington, DC. Available from, as of Mar 27, 2013:
      http://www.cosmeticsinfo.org] **PEER REVIEWED** 

      MEDICATION **PEER REVIEWED** 

      MEDICATION (VET) **PEER REVIEWED** 

MANUFACTURERS:
      Bentonite - Producer and Manufacture Data (2012)Company Site City State
      Zip Manufacture Import Lanxess Corp Rhein Chemie Corp Plant, 145 Parker
      Court Chardon OH 44024-1112   Penzoil Quaker State dba Shell Oil
      Penzoil-Quaker State Co, 700 Milam Houston TX 77002-2806  X Hallmark
      Crayola LLC Bethlehem Plt, 2475 Brodhead Rd Bethlehem PA 18020-8906  X
      Corning Inc Cormtech In 500 International Dr Durham NC 27712-8911  X NGK
      North America NGK Ceramics USA Inc, 119 Mazeppa Rd Moorseville NC 28115  
      Proctor & Gamble Co Proctor & Gamble Co, 1 Proctor And Gamble Plaza
      Cincinnati OH 45202-3392   Agrium Advanced Technologies Inc Agrium
      Advanced Technologies (US) Inc, 2405 Vassar Rd Reese MI 48757-9340  X
      Wyoben Inc Wyo-Ben Sage Creek Lovell WY 82431   Wyoben Inc Wyo-Ben, Inc
      Stucco Plant Greybull, WY 82426   Wyoben Inc Wyo-Ben Lucerne Plant
      Thermopolis WY 82443   [US EPA; Chemical Data Reporting (CDR).
      Non-confidential 2012 Chemical Data Reporting information on chemical
      production and use in the United Sates. Available from, as of Mar 25,
      2013: http://www.epa.gov/oppt/cdr/index.html] **PEER REVIEWED** 

      Bentonite - Producer and Manufacture Data (2006)Company Site City State
      Zip Manufacture Import Reckitt Benckiser Inc Reckitt Benckiser -
      Parsippany Parsippany NJ 07054 No Yes Sud Chemie A.G. Munchen Sud Chemie
      N.A. - Corporate Headquarters Louisville KY 40210 No Yes The Proctor &
      Gamble Co. Proctor & Gamble Co - Cincinnati Cincinnati OH 45202 No Yes [US
      EPA; Inventory Update Reporting (IUR). Non-confidential 2006 IUR Records
      by Chemical, including Manufacturing, Processing and Use Information.
      Washington, DC: U.S. Environmental Protection Agency. Available from, as
      of Mar 25, 2013: http://cfpub.epa.gov/iursearch/index.cfm] **PEER
      REVIEWED** 

      The leading producer companies were, in alphabetical order: American
      Colloid Co.; BASF SE; Bentonite Performance Minerals LLC; Black Hills
      Bentonite Co.; Nestle S.A. (fuller's earth); Oil-Dri Corp. of America
      (fuller's earth)[USGS; Minerals Yearbook 2010 Database on Clay and Shale.
      Available from, as of Mar 23, 2013:
      http://minerals.usgs.gov/minerals/pubs/commodity/clays/myb1-2010-clays.pdf]
      **PEER REVIEWED** 

      The 10 leading producer States were, in decreasing order of tonnage:
      Georgia, Wyoming, Texas, Alabama, Missouri, North Carolina, Ohio,
      Tennessee, Virginia, and Mississippi.[USGS; Minerals Yearbook 2010
      Database on Clay and Shale. Available from, as of Mar 23, 2013:
      http://minerals.usgs.gov/minerals/pubs/commodity/clays/myb1-2010-clays.pdf]
      **PEER REVIEWED** 

METHODS OF MANUFACTURING:
      Bentonite beneficiation and processing involves relatively simple milling
      techniques that involve crushing or shredding, drying, and grinding and
      screening to suitable sizes.[Gerhartz, W. (exec ed.). Ullmann's
      Encyclopedia of Industrial Chemistry. 5th ed.Vol A1: Deerfield Beach, FL:
      VCH Publishers, 1985 to Present., p. VA7: 124 (1986)] **PEER REVIEWED** 

      Virtually all bentonite is strip-mined.[Murray HH; Ullmann's Encyclopedia
      of Industrial Chemistry. 7th ed. (1999-2012). New York, NY: John Wiley
      & Sons; Clays. Online Posting Date: 15 Dec 2006] **PEER REVIEWED** 

GENERAL MANUFACTURING INFORMATION:
      Bentonite is a rock formed of highly colloidal and plastic clays composed
      mainly of montmorillonite, a clay mineral of the smectite group, and is
      produced by in situ devitrification of volcanic ash. In addition to
      montmorillonite, bentonite may contain feldspar, cristobalite, and
      crystalline quartz. The special properties of bentonite are an ability to
      form thixotrophic gels with water, an ability to absorb large quantities
      of water, and a high cation exchange capacity. The properties of bentonite
      are derived from the crystal structure of the smectite group, which is an
      octahedral alumina sheet between two tetrahedral silica sheets. Variations
      in interstitial water and exchangeable cations in the interlayer space
      affect the properties of bentonite and thus the commercial uses of the
      different types of bentonite. By extension, the term bentonite is applied
      commercially to any clay with similar properties. Fuller's earth is often
      a bentonite.[WHO; Environ Health Criteria 231: Bentonite, Kaolin, and
      Selected Clay Minerals (2005). Available from, as of April 3, 2013:
      http://www.inchem.org/pages/ehc.html] **PEER REVIEWED** 

      Bentonites in which sodium montmorillonites are the major mineral
      constituent commonly have a high swelling capacity. The largest and
      highest quality sodium bentonite deposits in the world are located in
      South Dakota, Wyoming, and Montana. These clays are commonly called
      Western or Wyoming bentonites.[Murray HH; Ullmann's Encyclopedia of
      Industrial Chemistry 7th ed. (1999-2013). NY, NY: John Wiley & Sons;
      Clays. Online Posting Date: December 15, 2006] **PEER REVIEWED** 

      Bentonites in which calcium montmorillonites are the major mineral
      constituent commonly have a low swelling capacity. These clays are
      generally referred to as Southern or subbentonites. Large deposits of
      these calcium bentonites occur in Texas and Mississippi.[Murray HH;
      Ullmann's Encyclopedia of Industrial Chemistry 7th ed. (1999-2013). NY,
      NY: John Wiley & Sons; Clays. Online Posting Date: December 15, 2006]
      **PEER REVIEWED** 

      Smectite is the name for a group of sodium, calcium, magnesium, iron,
      lithium aluminum silicates, which include the individual minerals sodium
      montmorillonite, calcium montmorillonite, nontronite, saponite, and
      hectorite. The rock in which these smectite minerals are usually dominant
      is bentonite. The name bentonite was first suggested in 1898 ...  and is
      the term commonly used to describe the industrial mineral. The term
      bentonite was defined /and/ ... restricted it to a clay material altered
      from a glassy igneous material, usually a tuff or volcanic ash. /It has
      been/ suggested that bentonite /is/ any clay composed dominantly of a
      smectite clay mineral and whose physical properties are dictated by this
      clay mineral. ...There are many clays designated as bentonite that did not
      originate by the alteration of volcanic ash or tuff. Therefore, the term
      bentonite usually does not include the mode of origin.[Murray HH;
      Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2012). New
      York, NY: John Wiley & Sons; Clays. Online Posting Date: 15 Dec 2006]
      **PEER REVIEWED** 

      Accepted in Europe as a food additive in certain applications. Included in
      the FDA Inactive Ingredients Database (oral capsules, tablets and
      suspensions, Topical suspensions, controlled release transdermal films and
      vaginal suppositories).[Rowe, R.C., Sheskey, P.J., Quinn, M.E.; (Eds.),
      Handbook of  Pharmaceutical Excipients 6th edition Pharmaceutical Press, 
      London, England 2009, p. 55] **PEER REVIEWED** 

      Volclay, a sodium form capable of absorbing five times its wt in water
      & swelling to 12-15 times its original vol, is used at up to 2% of
      feed ration (40 lb/ton) for cattle & sheep.[Rossoff, I.S. Handbook of
      Veterinary Drugs. New York: Springer Publishing Company, 1974., p. 40]
      **PEER REVIEWED** 

      In 1998, 19 companies produced bentonite from approximately 60 quarries in
      11 States.[USGS; Minerals Yearbook 1998uDatabase on Clay and Shale.
      Available from, as of August 25, 2000:
      http://mineralshttp://minerals.usgs.gov/minerals/pubs/commodity/c] **PEER
      REVIEWED** 

      The highest quality swelling clay is the yellowish green bentonite, which
      has been weathered and oxidized.[Murray HH; Ullmann's Encyclopedia of
      Industrial Chemistry. 7th ed. (1999-2012). New York, NY: John Wiley &
      Sons; Clays. Online Posting Date: 15 Dec 2006] **PEER REVIEWED** 

      The major nonclay minerals present in the Clay Spur bentonite are quartz,
      opal-CT, feldspar, mica, and some zeolite.[Murray HH; Ullmann's
      Encyclopedia of Industrial Chemistry. 7th ed. (1999-2012). New York, NY:
      John Wiley & Sons; Clays. Online Posting Date: 15 Dec 2006] **PEER
      REVIEWED** 

      In southern or subbentonites, quartz, feldspar and micas are the major
      nonclay minerals present.[Murray HH; Ullmann's Encyclopedia of Industrial
      Chemistry. 7th ed. (1999-2012). New York, NY: John Wiley & Sons;
      Clays. Online Posting Date: 15 Dec 2006] **PEER REVIEWED** 

      Quartz and micas are the major nonclay minerals in Tertiary
      bentonite.[Murray HH; Ullmann's Encyclopedia of Industrial Chemistry. 7th
      ed. (1999-2012). New York, NY: John Wiley & Sons; Clays. Online
      Posting Date: 15 Dec 2006] **PEER REVIEWED** 

      Cheto Arizona bentonite contains a small amount of kaolinite with quartz,
      micas, and feldspars as common non-clay impurities.[Murray HH; Ullmann's
      Encyclopedia of Industrial Chemistry. 7th ed. (1999-2012). New York, NY:
      John Wiley & Sons; Clays. Online Posting Date: 15 Dec 2006] **PEER
      REVIEWED** 

      In the English literature, bentonites are referred to as fuller's earth. 
      The term fuller's earth refers to any natural material that has the
      capacity to decolorize oil to an extent that is of commercial
      value.[Murray HH; Ullmann's Encyclopedia of Industrial Chemistry. 7th ed.
      (1999-2012). New York, NY: John Wiley & Sons; Clays. Online Posting
      Date: 15 Dec 2006] **PEER REVIEWED** 

      Bentonite (a Natural Hydrated Aluminium Silicate) is listed in the
      Cosmetics Directive of the European Union (Annex IV, Part I) as CI 77004,
      and may be used in all cosmetics and personal care products. When used as
      a color in cosmetic products in the European Union, this ingredient must
      be called CI 77004.[Personal Care Products Council; CosmeticsINFO.org.
      Washington, DC. Available from, as of Mar 27, 2013:
      http://www.cosmeticsinfo.org] **PEER REVIEWED** 

      The Food and Drug Administration (FDA) has reviewed the safety of ...
      bentonite and determined that /it is/ Generally Recognized as Safe (GRAS)
      for use as /a/ direct food additive[Personal Care Products Council;
      CosmeticsINFO.org. Washington, DC. Available from, as of Mar 27, 2013:
      http://www.cosmeticsinfo.org] **PEER REVIEWED** 

      High-swelling sodium bentonite ... is preferred for drilling muds,
      pelletizing iron ore, and sealing and waterproofing ... low-swelling
      calcium bentonite is preferred for filtering, clarifying, and absorbing
      and serving as a filler, stabilizer, extender, carrier, bonding agent, or
      catalyst. Both types are used in foundry sand.[IPCS; Environmental Health
      Criteria 231. Bentonite, Kaolin, and Selected Clay Minerals. Geneva,
      Switzerland: World Health Org, Internl Prog Chem Safety (2005)] **PEER
      REVIEWED** 

      Nanoclays are nanoparticles of layered mineral silicates. Depending on
      chemical composition and nanoparticle morphology, nanoclays are organized
      into several classes such as montmorillonite, bentonite, kaolinite,
      hectorite, and halloysite. Organically-modified nanoclays (organoclays)
      are an attractive class of hybrid organic-inorganic nanomaterials with
      potential uses in polymer nanocomposites, as rheological modifiers, gas
      absorbents and drug delivery carriers. /Nanoclays/[Sigma-Aldrich, Nano
      Minerals: Nanoclays. Available from, as of April 3, 2013:
      http://www.sigmaaldrich.com/materials-science/nanomaterials/nanoclay-building.html]
      **PEER REVIEWED** 

FORMULATIONS/PREPARATIONS:
      Hollander & McClanahan base is/ a hydrophilic base containing
      bentonite... /it contains/ petrolatum 32 g, bentonite 13 g, sodium lauryl
      sulfate 0.5 g, water 54 g, methylparaben 0.1 g /Bentonite USP/[Osol, A.
      and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th
      ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 1537] **PEER
      REVIEWED** 

      Bentonite USP: magma USP (5%) /contains/ bentonite 5 g /&/ purified
      water, to make 100 mL. Ointment /contains/ bentonite 15 g, propylene
      glycol 15 mL, /&/ petrolatum, to make 100 g. /Bentonite USP/[American
      Hospital Formulary Service. Volumes I and II. Washington, DC: American
      Society of Hospital Pharmacists, to 1984., p. 84:2412] **PEER REVIEWED** 

      Addition of a humectant (glycerin, sorbitol, etc) in amounts up to 10%
      will retard ... /drying/ action /of bentonite & water ointments/.
      /Bentonite USP/[Osol, A. and J.E. Hoover, et al. (eds.). Remington's
      Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing
      Co., 1975., p. 1537] **PEER REVIEWED** 

      Depending on sequence of mixing it is possible to prepare both oil/water
      and water/oil emulsions. When oil/water emulsion is desired, bentonite is
      first dispersed in water and allowed to hydrate so as to form a magma. The
      oil-phase phase is then added gradually with constant trituration. Because
      the aqueous phase is always in excess, the oil/water emulsion type is
      favored. To prepare water/oil emulsion, bentonite is first dispersed in
      oil; water is then added gradually.[Troy, D.B. (Ed); Remmington The
      Science and Practice of Pharmacy. 21 st Edition. Lippincott Williams &
      Williams, Philadelphia, PA 2005, p. 331] **PEER REVIEWED** 

      "Flo-Fre" - trademark for flowability aid for soybean meal and other
      feeds[Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th 
      Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 570] **PEER
      REVIEWED** 

      There are two varieties: (1) sodium bentonite (Wyoming or western), which
      has high swelling capacity in water; and (2) calcium bentonite (southern),
      with negligible swelling capacity.[Lewis, R.J. Sr.; Hawley's Condensed
      Chemical Dictionary 15th  Edition. John Wiley & Sons, Inc. New York,
      NY 2007., p. 132] **PEER REVIEWED** 

IMPURITIES:
      Cheto Arizona bentonite contains a small amount of kaolinite with quartz,
      micas, and feldspars as common non-clay impurities.[Murray HH; Ullmann's
      Encyclopedia of Industrial Chemistry. 7th ed. (1999-2012). New York, NY:
      John Wiley & Sons; Clays. Online Posting Date: 15 Dec 2006] **PEER
      REVIEWED** 

      The principle constituent is Montmorillonite. However, other minerals such
      as illite, kaolinite, and nonargillaceous detrital minerals can be
      present. Most Bentonites appear relatively pure and other mineral
      contributions rarely exceed 10%. Cristobalite is often present.
      Montmorillonite compositions frequently vary either in its lattice
      structure or in the exchangeable ions present.[Cosmetic Ingredient Review;
      Final Report of the Cosmetic Ingredient Review Expert Panel; Final Report
      on the Safety Assessment of Aluminum Silicate, Calcium Silicate, Magnesium
      Aluminum Silicate, Magnesium Silicate, Magnesium Trisilicate, Sodium
      Magnesium Silicate, Zirconium Silicate, Attapulgite, Bentonite, Fuller's
      Earth, Hectorite, Kaolin, Lithium Magnesium Silicate, Lithium Magnesium
      Sodium Silicate, Montmorillonite, Pyrophyllite, and Zeolite; International
      Journal of Toxicology 22 (Suppl 1): 37-102 (2003)] **PEER REVIEWED** 

CONSUMPTION PATTERNS:
      32% FOR IRON ORE PELLETIZING; 26% FOR DRILLING MUD; 25% FOR FOUNDRY SAND;
      6% FOR MFR OF ANIMAL FEED; 4% FOR PURIFYING OILS; 1% FOR WATERPROOFING AND
      SEALING; 1% FOR PET LITTER ABSORBENT; AND 5% FOR MISCELLANEOUS USES
      (1975)[SRI] **PEER REVIEWED** 

      Domestic consumption decreased by approximately 2% in 1998. ... Domestic
      sales of bentonite for major markets were 869,000 ton for foundry sand
      bond, 773,000 ton for pet waste absorbent, 665,000 t for drilling mud,
      529,000 ton for iron ore pelletizing, and 236,000 ton for sealant
      applications.[USGS; Minerals Yearbook 1998 Database on Clay and Shale.
      Available from, as of August 25, 2000:
      http://minerals.usgs.gov/minerals/pubs/commodity/clays/] **PEER REVIEWED**
      
      Total sales (domestic and exports) of swelling bentonite were
      approximately 725,000 t for drilling mud, 840,00 t for foundry sand bond,
      588,000 t for pelletizing iron ore, 775,000 t for pet waste absorbent, and
      143,000 t for waterproofing and sealing.[USGS; Minerals Yearbook 1998
      Database on Clay and Shale. Available from, as of August 25, 2000:
      http://minerals.usgs.gov/minerals/pubs/commodity/clays/] **PEER REVIEWED**
      
      Reported domestic sales of bentonite were 1.02 million metric tons (Mt)
      for drilling mud (all swelling bentonite), 423,000 tons for foundry sand
      bond (more than 99% was swelling bentonite), 595,000 tons for pelletizing
      iron ore (all swelling bentonite), and 967,000 tons for pet waste
      absorbent (all swelling bentonite). Bentonite also was sold for civil
      engineering and sealing; fillers, extenders, and binders; waterproofing
      and sealing; and a variety of other applications. ... Domestic sales of
      bentonite increased for pet litter, drilling mud, pelletizing iron ore,
      waterproofing and sealing, and miscellaneous uses. Domestic sales of
      bentonite for drilling mud use increased by 74%, and export sales
      increased by 52%. Drilling activity increased domestically and overseas in
      2010 compared with 2009. ...[USGS; Minerals Yearbook 2010 Database on Clay
      and Shale. Available from, as of Mar 23, 2013:
      http://minerals.usgs.gov/minerals/pubs/commodity/clays/myb1-2010-clays.pdf]
      **PEER REVIEWED** 

      /Bentonite Uses (estimated):/ 30% drilling mud, 27% absorbents, 14% iron
      ore pelletizing, 16% foundry sand bond, and 13% other uses.[USGS; Mineral
      Commodity Summaries 2013. Clays. Available from, as of March 28, 2013:
      http://minerals.usgs.gov/minerals/pubs/mcs/2013/mcs2013.pdf] **PEER
      REVIEWED** 

      Bentonite sold or used by producers in the United States, by type and use.
      (Data are rounded to no more than three significant digits; may not add to
      totals shown.)Bentonite sold or used producers in the United States, by
      type and use (Thousand metric tons and thosuand dollars)Quantity (2009)
      Value (2009) Quantity (2010) Value (2010) TYPE:     Nonswelling 116 8,140
      123 9,320 Swelling 3,530 198,000 4,510 252,000 Total 3,650 207,000 4,630
      261,000 -     USE: Domestic     Pet waste absorbents 925 (estimated) Not
      Available 967 (estimated) Not Available Adhesives 9 Not Available 8 Not
      Available Animal feed 60 Not Available 71 Not Available Drilling mud 587
      Not Available 1,020 Not Available Filler and extender applications
      (Includes asphalt tiles, asphalt emulsions, cosmetics, fertilizers, ink,
      medical, miscellaneous fillers and extenders applications, paint, paper
      coating, paper filling, pesticides and related products, pharmaceuticals,
      and plastics.) 69 Not Available 104 Not Available Foundry sand 443
      (estimated) Not Available 423 (estimated) Not Available Pelletizing (iorn
      ore) 445 (estimated) Not Available 595 (estimated) Not Available
      Waterproofing and sealing 102 Not Available 122 Not Available
      Miscellaneous civil engineering 190 (estimated) Not Available 192
      (estimated) Not Available Miscellaneous (Includes ceramics, chemical
      manufacturing, clarifying and decolorizing, heavy-clay products, oil and
      grease absorbents, refractories, and other unknown uses.) 170 Not
      Available 310 Not Available Total 3,000 (estimated) Not Available 3,810
      (estimated) Not Available -     USE: Exports, reported by producers    
      Drilling mud 105 (estimated) Not Available 160 (estimated) Not Available
      Foundry sand 192 Not Available 121 Not Available Other (Includes
      absorbents, fillers and extenders, refractories, pelletizing, and other
      unknown uses.) 349 Not Available 536 Not Available Total 646 (estimated)
      Not Available 817 (estimated) Not Available -     Grand total 3,650
      207,000 4,630 261,000 [USGS; Minerals Yearbook 2010 Database on Clay and
      Shale. Available from, as of Mar 23, 2013:
      http://minerals.usgs.gov/minerals/pubs/commodity/clays/myb1-2010-clays.pdf]
      **PEER REVIEWED** 

U. S. PRODUCTION:
      (1972) 2.51X10+12 GRAMS[SRI] **PEER REVIEWED** 

      (1975) 2.52X10+12 GRAMS[SRI] **PEER REVIEWED** 

      In thousand metric tons: (1995) 3,820; (1996) 3,740; (1997) 4,020; (1998)
      3,820; (1999, est) 3,850[USGS; Minerals Commodity Summaries 2000 Database
      on Clays. Available from, as of August 25, 2000:
      http://minerals.usgs.gov/minerals/pubs/commodity/clays] **PEER REVIEWED** 

      Production volume for non-confidential chemicals reported under the 2006
      Inventory Update Rule. Chemical: Bentonite. Aggregated National Production
      Volume: 10 to   <  50 million pounds.[US EPA; Non-Confidential 2006
      Inventory Update Reporting. National Chemical Information. Bentonite
      (1302-78-9). Available from, as of March 28, 2013:
      http://cfpub.epa.gov/iursearch/index.cfm?s=chem&err=t] **PEER
      REVIEWED** 

      Non-confidential 2012 Chemical Data Reporting (CDR) information on the
      production and use of chemicals manufactured or imported into the United
      States. Chemical: Bentonite. National Production Volume: 1,000,000,000 -
      5,000,000,000 pounds/year.[USEPA/Pollution Prevention and Toxics; 2012
      Chemical Data Reporting Database. Bentonite (1302-78-9). Available from,
      as of March 28, 2013: http://java.epa.gov/oppt_chemical_search/] **PEER
      REVIEWED** 

      Bentonite: Salient Production Statistics for the United StatesData in
      thousand metric tonsProduction (sold or used) 2008 2009 2010 2011 2012
      (estimated) Bentonite 4,910 3,650 4,630 4,810 4,800 [USGS; Mineral
      Commodity Summaries 2013. Clays. Available from, as of March 28, 2013:
      http://minerals.usgs.gov/minerals/pubs/mcs/2013/mcs2013.pdf] **PEER
      REVIEWED** 

      Bentonite world mine production and reserves:Bentonite World Mine
      Production and Reserves (Data in thousand metric tons)Year 2011 Year 2012
      (Estimated) United States (sales) 4,810 4,800 Brazil (beneficated) 532 540
      Czech Republic (crude) 160 180 Germany (sales) 350 350 Greece (crude) 850
      900 Italy 110 110 Mexico 54 54 Spain 155 160 Turkey 1,000 1,000 Ukraine
      (crude) 185 210 Other countries 2,100 2,000 World total (rounded) 10,300
      10,000 [USGS; Mineral Commodity Summaries 2013. Clays. Available from, as
      of March 28, 2013:
      http://minerals.usgs.gov/minerals/pubs/mcs/2013/mcs2013.pdf] **PEER
      REVIEWED** 

U. S. IMPORTS:
      (1972) 2.59X10+9 GRAMS[SRI] **PEER REVIEWED** 

      (1975) 2.14X10+9 GRAMS[SRI] **PEER REVIEWED** 

      Bentonite imports consisted mainly of untreated bentonite clay and
      chemically or artificially activated materials. ... untreated bentonite
      were 6,600 t ... chemically activated material were 18,900 t ...[USGS;
      Minerals Yearbook 1998 Database on Clay and Shale. Available from, as of
      August 25, 2000: http://minerals.usgs.gov/minerals/pubs/commodity/clays/]
      **PEER REVIEWED** 

U. S. EXPORTS:
      (1972) 4.73X10+11 GRAMS[SRI] **PEER REVIEWED** 

      (1975) 4.05X10+11 GRAMS[SRI] **PEER REVIEWED** 

      Domestic bentonite producers reported exports of 427,000 t. ... exports
      destined for Canadian and Mexican markets (approximately 250,000 t).[USGS;
      Minerals Yearbook 1998 Database on Clay and Shale. Available from, as of
      August 25, 2000: http://minerals.usgs.gov/minerals/pubs/commodity/clays/]
      **PEER REVIEWED** 

      The major export markets /for swelling bentonite/ were in drilling mud,
      foundry sand, and iron ore pelletizing applications.[USGS; Minerals
      Yearbook 1998 Database on Clay and Shale. Available from, as of August 25,
      2000: http://minerals.usgs.gov/minerals/pubs/commodity/clays/] **PEER
      REVIEWED** 

      Exports /for nonswelling bentonite/ were limited to filtering, clarifying,
      and decolorizing of oils and greases and foundry sand applications.[USGS;
      Minerals Yearbook 1998 Database on Clay and Shale. Available from, as of
      August 25, 2000: http://minerals.usgs.gov/minerals/pubs/commodity/clays/]
      **PEER REVIEWED** 

      Bentonite: Salient Export Statistics for the United StatesData in thousand
      metric tonsExports 2008 2009 2010 2011 2012 (estimated) Bentonite 1,090
      709 953 1,020 1,000 [USGS; Mineral Commodity Summaries 2013. Clays.
      Available from, as of March 28, 2013:
      http://minerals.usgs.gov/minerals/pubs/mcs/2013/mcs2013.pdf] **PEER
      REVIEWED** 

LABORATORY METHODS:

CLINICAL LABORATORY METHODS:
      Energy-dispersive X-ray analysis (EDXA) - also referred to as
      energy-dispersive X-ray microanalysis, X-ray microanalysis, electron
      microscopic microanalysis, and energy-dispersive X-ray spectrometry - and
      electron diffraction may permit the rapid identification of individual
      clay mineral particles and have been applied particularly to the
      identification of inhaled particles sampled via bronchoalveolar lavage or
      from lung specimens. EDXA requires a scanning or transmission electron
      microscope equipped with an energy-dispersive X-ray spectrometer and
      appropriate mathematical tools for analysing the resulting spectra. EDXA
      identifies and quantifies elements above atomic number 8. Since the basic
      classification of clay minerals is based on structural formula and the
      atomic composition is similar for many different clay minerals, EDXA
      cannot provide secure identification except by comparison with standards
      previously identified by other means. Application of EDXA without
      appropriate standards is likely to generate significant errors. In
      practice, EDXA is ordinarily combined with conventional transmission
      electron microscopy to first visualize a particle. Probe size is then
      adjusted downward so that only the selected particle is analysed. The best
      results are obtained by operating the microanalysis in scanning
      transmission mode. /Clay mineral particles/[WHO; Environ Health Criteria
      231: Bentonite, Kaolin, and Selected Clay Minerals (2005). Available from,
      as of April 3, 2013: http://www.inchem.org/pages/ehc.html] **PEER
      REVIEWED** 

ANALYTIC LABORATORY METHODS:
      There is no single or simple procedure for the positive identification of
      montmorillonite-group or other aluminosilicates or for their
      quantification in dust and other samples. The application of several
      methods may be necessary for even approximate identification and rough
      quantification. These methods include X-ray diffraction, electron
      microscopy, energy-dispersive X-ray analysis, differential thermal
      analysis, and infrared spectroscopy. In the past, chemical methods based
      on differences in resistance of various clay minerals to chemical attack,
      the so-called "rational methods of analysis," were used.[WHO; Environ
      Health Criteria 231: Bentonite, Kaolin, and Selected Clay Minerals (2005).
      Available from, as of April 3, 2013: http://www.inchem.org/pages/ehc.html]
      **PEER REVIEWED** 

SPECIAL REFERENCES:

SPECIAL REPORTS:
      Final report on the safety assessment of aluminum silicate, calcium
      silicate, magnesium aluminum silicate, magnesium silicate, magnesium
      trisilicate, sodium magnesium silicate, zirconium silicate, attapulgite,
      bentonite, Fuller's earth, hectorite, kaolin, lithium magnesium silicate,
      lithium magnesium sodium silicate, montmorillonite, pyrophyllite, and
      zeolite.[Elmore AR, Cosmetic Ingredient Review Expert Panel; Int J Toxicol
      22 (Suppl 1): 37-102 (2003)] 

SYNONYMS AND IDENTIFIERS:

RELATED HSDB RECORDS:
      8118 [Montmorillonite] (mixture)

SYNONYMS:
      Albagel Premium USP 4444[WHO; Environ Health Criteria 231: Bentonite,
      Kaolin, and Selected Clay Minerals (2005). Available from, as of April 3,
      2013: http://www.inchem.org/pages/ehc.html] **PEER REVIEWED** 

      Bentonite 2073[WHO; Environ Health Criteria 231: Bentonite, Kaolin, and
      Selected Clay Minerals (2005). Available from, as of April 3, 2013:
      http://www.inchem.org/pages/ehc.html] **PEER REVIEWED** 

      Bentonite magma[WHO; Environ Health Criteria 231: Bentonite, Kaolin, and
      Selected Clay Minerals (2005). Available from, as of April 3, 2013:
      http://www.inchem.org/pages/ehc.html] **PEER REVIEWED** 

      COLLOIDAL CLAY[Sax, N.I. Dangerous Properties of Industrial Materials. 5th
      ed. New York: Van Nostrand Rheinhold, 1979., p. 402] **PEER REVIEWED** 

      CI 77004[Cosmetic Ingredient Review; Final Report of the Cosmetic
      Ingredient Review Expert Panel; Final Report on the Safety Assessment of
      Aluminum Silicate, Calcium Silicate, Magnesium Aluminum Silicate,
      Magnesium Silicate, Magnesium Trisilicate, Sodium Magnesium Silicate,
      Zirconium Silicate, Attapulgite, Bentonite, Fuller's Earth, Hectorite,
      Kaolin, Lithium Magnesium Silicate, Lithium Magnesium Sodium Silicate,
      Montmorillonite, Pyrophyllite, and Zeolite; International Journal of
      Toxicology 22 (Suppl 1): 37-102 (2003)] **PEER REVIEWED** 

      E558[Rowe, R.C., Sheskey, P.J., Quinn, M.E.; (Eds.), Handbook of 
      Pharmaceutical Excipients 6th edition Pharmaceutical Press,  London,
      England 2009, p. 53] **PEER REVIEWED** 

      MAGBOND[U.S. Department of Health and Human Services, Public Health
      Service, Center for Disease Control, National Institute for Occupational
      Safety Health. Registry of Toxic Effects of Chemical Substances (RTECS).
      National Library of Medicine's current MEDLARS file., p. 82/8012] **PEER
      REVIEWED** 

      OTAYLITE **PEER REVIEWED** 

      Soap clay[Cosmetic Ingredient Review; Final Report of the Cosmetic
      Ingredient Review Expert Panel; Final Report on the Safety Assessment of
      Aluminum Silicate, Calcium Silicate, Magnesium Aluminum Silicate,
      Magnesium Silicate, Magnesium Trisilicate, Sodium Magnesium Silicate,
      Zirconium Silicate, Attapulgite, Bentonite, Fuller's Earth, Hectorite,
      Kaolin, Lithium Magnesium Silicate, Lithium Magnesium Sodium Silicate,
      Montmorillonite, Pyrophyllite, and Zeolite; International Journal of
      Toxicology 22 (Suppl 1): 37-102 (2003)] **PEER REVIEWED** 

      SOUTHERN BENTONITE[Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of
      Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons,
      Inc. Hoboken, NJ. 2004., p. 351] **PEER REVIEWED** 

      TIXOTON[Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial
      Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc.
      Hoboken, NJ. 2004., p. 351] **PEER REVIEWED** 

      Taylorite[Rowe, R.C., Sheskey, P.J., Quinn, M.E.; (Eds.), Handbook of 
      Pharmaceutical Excipients 6th edition Pharmaceutical Press,  London,
      England 2009, p. 53] **PEER REVIEWED** 

      Volclay[Cosmetic Ingredient Review; Final Report of the Cosmetic
      Ingredient Review Expert Panel; Final Report on the Safety Assessment of
      Aluminum Silicate, Calcium Silicate, Magnesium Aluminum Silicate,
      Magnesium Silicate, Magnesium Trisilicate, Sodium Magnesium Silicate,
      Zirconium Silicate, Attapulgite, Bentonite, Fuller's Earth, Hectorite,
      Kaolin, Lithium Magnesium Silicate, Lithium Magnesium Sodium Silicate,
      Montmorillonite, Pyrophyllite, and Zeolite; International Journal of
      Toxicology 22 (Suppl 1): 37-102 (2003)] **PEER REVIEWED** 

      Wilkinite[O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of
      Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ:  Merck and Co.,
      Inc., 2006., p. 175] **PEER REVIEWED** 

      WILKONITE[Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial
      Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc.
      Hoboken, NJ. 2004., p. 351] **PEER REVIEWED** 

FORMULATIONS/PREPARATIONS:
      Hollander & McClanahan base is/ a hydrophilic base containing
      bentonite... /it contains/ petrolatum 32 g, bentonite 13 g, sodium lauryl
      sulfate 0.5 g, water 54 g, methylparaben 0.1 g /Bentonite USP/[Osol, A.
      and J.E. Hoover, et al. (eds.). Remington's Pharmaceutical Sciences. 15th
      ed. Easton, Pennsylvania: Mack Publishing Co., 1975., p. 1537] **PEER
      REVIEWED** 

      Bentonite USP: magma USP (5%) /contains/ bentonite 5 g /&/ purified
      water, to make 100 mL. Ointment /contains/ bentonite 15 g, propylene
      glycol 15 mL, /&/ petrolatum, to make 100 g. /Bentonite USP/[American
      Hospital Formulary Service. Volumes I and II. Washington, DC: American
      Society of Hospital Pharmacists, to 1984., p. 84:2412] **PEER REVIEWED** 

      Addition of a humectant (glycerin, sorbitol, etc) in amounts up to 10%
      will retard ... /drying/ action /of bentonite & water ointments/.
      /Bentonite USP/[Osol, A. and J.E. Hoover, et al. (eds.). Remington's
      Pharmaceutical Sciences. 15th ed. Easton, Pennsylvania: Mack Publishing
      Co., 1975., p. 1537] **PEER REVIEWED** 

      Depending on sequence of mixing it is possible to prepare both oil/water
      and water/oil emulsions. When oil/water emulsion is desired, bentonite is
      first dispersed in water and allowed to hydrate so as to form a magma. The
      oil-phase phase is then added gradually with constant trituration. Because
      the aqueous phase is always in excess, the oil/water emulsion type is
      favored. To prepare water/oil emulsion, bentonite is first dispersed in
      oil; water is then added gradually.[Troy, D.B. (Ed); Remmington The
      Science and Practice of Pharmacy. 21 st Edition. Lippincott Williams &
      Williams, Philadelphia, PA 2005, p. 331] **PEER REVIEWED** 

      "Flo-Fre" - trademark for flowability aid for soybean meal and other
      feeds[Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th 
      Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 570] **PEER
      REVIEWED** 

      There are two varieties: (1) sodium bentonite (Wyoming or western), which
      has high swelling capacity in water; and (2) calcium bentonite (southern),
      with negligible swelling capacity.[Lewis, R.J. Sr.; Hawley's Condensed
      Chemical Dictionary 15th  Edition. John Wiley & Sons, Inc. New York,
      NY 2007., p. 132] **PEER REVIEWED** 

ADMINISTRATIVE INFORMATION:

HAZARDOUS SUBSTANCES DATABANK NUMBER: 392

LAST REVISION DATE: 20130617

LAST REVIEW DATE: Reviewed by SRP on 5/16/2013

UPDATE HISTORY:
      Complete Update on 2013-06-17, 45 fields added/edited/deleted

      Field Update on 2008-09-11, 1 fields added/edited/deleted

      Field Update on 2008-06-26, 1 fields added/edited/deleted

      Complete Update on 02/14/2003, 1 field added/edited/deleted.

      Complete Update on 01/14/2002, 1 field added/edited/deleted.

      Complete Update on 08/09/2001, 1 field added/edited/deleted.

      Complete Update on 04/26/2001, 22 fields added/edited/deleted.

      Complete Update on 08/26/1999, 1 field added/edited/deleted.

      Complete Update on 03/19/1999, 1 field added/edited/deleted.

      Complete Update on 03/25/1998, 4 fields added/edited/deleted.

      Field Update on 02/25/1998, 1 field added/edited/deleted.

      Field Update on 05/01/1997, 2 fields added/edited/deleted.

      Field Update on 07/11/1996, 1 field added/edited/deleted.

      Field Update on 01/19/1996, 1 field added/edited/deleted.

      Field Update on 12/21/1994, 1 field added/edited/deleted.

      Field Update on 11/03/1994, 1 field added/edited/deleted.

      Field Update on 11/02/1994, 1 field added/edited/deleted.

      Complete Update on 03/25/1994, 1 field added/edited/deleted.

      Field update on 12/12/1992, 1 field added/edited/deleted.

      Field update on 08/13/1990, 1 field added/edited/deleted.

Complete Update on 12/14/1984

Created 19830401 by SYS