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 July 17, 2013.

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:

EMT COPYRIGHT DISCLAIMER:

The information contained in the Truven Health Analytics Inc. products is

intended as an educational aid only. All treatments or procedures are intended

to serve as an information resource for physicians or other competent healthcare

professionals performing the consultation or evaluation of patients and must be

interpreted in view of all attendant circumstances, indications and
contraindications.

The use of the Truven Health Analytics Inc. products is at

your sole risk. These products are provided "as is" and "as available" for use,

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products. All implied warranties of merchantability and fitness for a particular

purpose or use are hereby excluded. Truven Health Analytics Inc. does not assume

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