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CHEMINFO Record Number: 526
CCOHS Chemical Name: Sodium stearate

Octadecanoic acid, sodium salt
Stearic acid, sodium salt
Sodium octadecanoate
Stéarate de sodium

CAS Registry Number: 822-16-2
RTECS Number(s): WI4725000
EU EINECS/ELINCS Number: 212-490-5
Chemical Family: Saturated aliphatic carboxylic acid salt / saturated aliphatic monocarboxylic acid salt / alkanoic acid salt / stearate / sodium salt
Molecular Formula: C18-H35-Na-O2
Structural Formula: CH3-(CH2)16-CO2-.Nat


Appearance and Odour:
White powder with fatty (tallow) odour.

Odour Threshold:
No information available

Warning Properties:
Insufficient information for evaluation.

Commercial sodium stearate can contain sodium palmitate, sodium salts of other fatty acids and approximately 1.3% free fatty acids (predominantly C16 and C18 acids) as impurities. This summary contains the available information specific to sodium stearate supplemented with general information on stearate salts which is applicable to sodium stearate.

Uses and Occurrences:
Sodium stearate is the most common soap ingredient. It is used in a variety of cleaning products; as a waterproofing and gelling agent in toothpaste and cosmetics; as a stabilizer in plastics; and as a food additive (binder, emulsifier and anticaking agent).


White, powder with fatty (tallow) odour. COMBUSTIBLE DUST. Can form explosive dust-air mixtures. Essentially non-toxic.


Effects of Short-Term (Acute) Exposure

Stearate salts, like sodium stearate, are practically non-toxic. High concentrations of dust may cause coughing and mild temporary irritation.

Skin Contact:
Sodium stearate is probably not irritating. A 100% solution produced no irritation in an animal test. In a 24-hour patch test using 0.5% sodium stearate in a water solution, 16/20 volunteers had no irritation, while 4/20 had minimal to moderate irritation. This was considered "an acceptable and typical soap response". It is not absorbed through the skin in a significant amount.(1)

Eye Contact:
Dust or mist (solutions) may be slightly irritating to the eyes. Some tearing, blinking and mild temporary pain may occur as material is rinsed from the eye by tears. It caused negligible irritation in an animal test.

Ingestion of sodium stearate can probably cause irritation, nausea, diarrhea, and occasionally vomiting. No specific information is available, but these effects are typical after ingestion of soaps and anionic surfactants.(2) Limited animal information indicates that the oral toxicity is low. Ingestion is not a typical route of occupational exposure.

Effects of Long-Term (Chronic) Exposure

Lungs/Respiratory System:
Long industrial experience with sodium stearate has shown that it can cause only minor, reversible effects on the lungs.(3) In general, long-term exposures to high concentrations of dust may cause increased mucous flow in the nose and airways of the respiratory system. This condition usually disappears after exposure stops.(4)

Sodium stearate can remove natural oils from the skin causing redness, drying and itching (dermatitis).

Skin Sensitization:
Sodium stearate is not an occupational skin sensitizer.
A stick deodorant containing 7% sodium stearate was tested on 212 people. The challenge test, conducted 2 weeks after the final patch test, resulted in 7 cases of slight irritation after 24 hours and one case after 48 hours. All were negative after 72 hours.(1)
Sensitization was not seen in 100 people tested with a formulation containing 0.3 to 0.75% sodium stearate.(1)


No specific information available. Probably not carcinogenic.

The International Agency for Research on Cancer (IARC) has not evaluated the carcinogenicity of this chemical.

The American Conference of Governmental Industrial Hygienists (ACGIH) has designated this chemical as not classifiable as a human carcinogen (A4).

The US National Toxicology Program (NTP) has not listed this chemical in its report on carcinogens.

Teratogenicity and Embryotoxicity:
No specific information available. Probably not teratogenic or embryotoxic.

Reproductive Toxicity:
No specific information available. Probably not a reproductive hazard.

No specific information available. Probably not mutagenic.

Toxicologically Synergistic Materials:
No information available

Potential for Accumulation:
Sodium stearate can enter the body mainly by ingestion. Skin absorption is very low. Injection studies in rats showed that negligible amounts of sodium stearate and its metabolites were eliminated in the urine or feces. Most of the dose was eliminated as carbon dioxide in the expired air (about 38%) or retained in the body (about 56%).(1)


If symptoms are experienced, remove source of contamination or move victim to fresh air and obtain medical advice.

Skin Contact:
No health effects expected. Quickly and gently blot or brush away excess chemical. Wash gently and thoroughly with water and non-abrasive soap for 5 minutes or until chemical is removed.

Eye Contact:
Do not allow victim to rub eye(s). Let the eye(s) water naturally for a few minutes. Have victim look right and left, and then up and down. If particle/dust does not dislodge, flush with lukewarm, gently flowing water for 5 minutes or until particle/dust is removed, while holding eyelid(s) open. If irritation persists, obtain medical attention. DO NOT attempt to manually remove anything stuck to eye(s).

If irritation or discomfort occur, obtain medical advice immediately.

First Aid Comments:
Consult a doctor and/or the nearest Poison Control Centre for all exposures except under minor instances of inhalation or skin contact. All first aid procedures should be periodically reviewed by a doctor familiar with the material and its conditions of use in the workplace.


Flash Point:
Not applicable.

Lower Flammable (Explosive) Limit (LFL/LEL):
Not applicable

Upper Flammable (Explosive) Limit (UFL/UEL):
Not applicable

Autoignition (Ignition) Temperature:
Not available

Sensitivity to Mechanical Impact:
Not sensitive. Stable material.

Flammable Properties:

Extinguishing Media:
Carbon dioxide, dry chemical powder, alcohol foam, polymer foam, water fog or mist.

Fire Fighting Instructions:
Evacuate area and fight fire from a safe distance or a protected location. Approach fire from upwind to avoid toxic decomposition products.
Avoid generating dust to minimize risk of explosion. Water spray, fog or foam can be used to extinguish fires involving sodium stearate. Water or foam may cause frothing. However, a water spray or fog that is gently applied to the surface of the liquid, preferably with a fine spray or fog nozzle, will cause frothing that will blanket and extinguish the fire. In addition, water can be used in the form of spray or fog to prevent dust formation, absorb heat, keep containers cool and protect fire-exposed material. Solid streams of water may be ineffective and spread material.
As in any fire, wear self-contained breathing apparatus (SCBA), pressure-demand, (MSHA/NIOSH approved or equivalent) and full protective equipment (Bunker Gear).


NFPA - Comments:
NFPA has no listing for this chemical in Codes 49 or 325.


Molecular Weight: 306.47

Conversion Factor:
Not applicable

Physical State: Solid
Melting Point: Not available
Boiling Point: Not available
Relative Density (Specific Gravity): Not available
Solubility in Water: Slowly soluble in cold water; freely soluble in hot water.(1)
Solubility in Other Liquids: Slowly soluble in cold ethanol, other cold alcohols and cold glycols; freely soluble in hot alcohols and glycols.(1)
Coefficient of Oil/Water Distribution (Partition Coefficient): Not applicable
pH Value: Strongly alkaline (saturated aqueous solution) (1)
Vapour Density: Not applicable
Vapour Pressure: Essentially zero
Saturation Vapour Concentration: Not applicable
Evaporation Rate: Not applicable


Normally stable. Decomposes in the presence of light.(8)

Hazardous Polymerization:
Will not occur.

Incompatibility - Materials to Avoid:

NOTE: Chemical reactions that could result in a hazardous situation (e.g. generation of flammable or toxic chemicals, fire or detonation) are listed here. Many of these reactions can be done safely if specific control measures (e.g. cooling of the reaction) are in place. Although not intended to be complete, an overview of important reactions involving common chemicals is provided to assist in the development of safe work practices.

ACIDS - react vigorously.

Hazardous Decomposition Products:
None known

Conditions to Avoid:
Static charge, sparks, heat and other ignition sources, generation of dust.

Corrosivity to Metals:
Not corrosive


No standard toxicity values are available for pure sodium stearate.

LD50 (oral, rat): Greater than 5000 mg/kg (25% solution in propylene glycol) (1, unconfirmed)

LD50 (dermal, rabbit): Greater than 3000 mg/kg (10-25% sodium stearate in a 20% bath soap/detergent product) (1, unconfirmed)

Eye Irritation:

100% solution produced negligible irritation in rabbits in a Draize test.(1)

Skin Irritation:

Application of a 100% solution produced no irritation in rabbits (no further details are given).(1)


Selected Bibliography:
(1) Final report of the safety assessment of lithium stearate, aluminum distearate, aluminum stearate, aluminum tristearate, ammonium stearate, calcium stearate, magnesium stearate, potassium stearate, sodium stearate, zinc stearate. Journal of the American College of Toxicology. Vol. 1, no. 2 (1982). p. 143-177
(2) Martindale : the extra pharmacopoeia. 29th edition. The Pharmaceutical Press, 1989. p. 1416-1417
(3) Documentation of the threshold limit values and biological exposure indices. 5th ed. ACGIH, 1986. p. 445, 536.1(86)- 536.2(86)
(4) Wright, G.W. The pulmonary effects of inhaled inorganic dust. In: Patty's industrial hygiene and toxicology. 4th. edition. Vol. 1, Part A. John Wiley & Sons, 1994. p. 307-309
(5) Grossel, S.S. Safety considerations in conveying of bulk solids and powders. Journal of Loss Prevention in the Process Industries. Vol. 1 (April, 1988). p. 62-74
(6) Field, P. Explosibility assessment of industrial powders and dusts. Building Research Establishment, 1983
(7) Schwab, R.F. Dusts. In: Fire protection handbook. Edited by A.E. Cote. 18th edition. National Fire Protection Association, 1991. p. 4-174 to 4-181.
(8) HSDB record for sodium stearate. Last revision date: 9308
(9) Occupational Safety and Health Administration (OSHA). Metal and Metalloid Particulates in Workplace Atmospheres (Atomic Absorption). In: OSHA Analytical Methods Manual. Revision Date: Oct. 31, 2001. Available at:
(10) National Institute for Occupational Safety and Health (NIOSH). Alkaline Dusts. In:NIOSH Manual of Analytical Methods (NMAM(R)). 4th ed. Edited by M.E. Cassinelli, et al. DHHS (NIOSH) Publication 94-113. Aug. 1994. Available at: <>
(11) National Institute for Occupational Safety and Health (NIOSH). Particulates Not Otherwise Regulated, Total. In: NIOSH Manual of Analytical Methods (NMAM(R)). 4th ed. Edited by M.E. Cassinelli, et al. DHHS (NIOSH) Publication 94-113. Aug. 1994. Available at: <>
(12) National Institute for Occupational Safety and Health (NIOSH). Particulates Not Otherwise Regulated, Respirable. In: NIOSH Manual of Analytical Methods (NMAM(R)). 4th ed. Edited by M.E. Cassinelli, et al. DHHS (NIOSH) Publication 94-113. Aug. 1994. Available at: <>

Information on chemicals reviewed in the CHEMINFO database is drawn from a number of publicly available sources. A list of general references used to compile CHEMINFO records is available in the database Help.

Review/Preparation Date: 1995-01-05

Revision Indicators:
EU class 1996-04-01
US transport 1996-04-01
Resistance of materials 1996-04-01
Protective equipment 1996-04-01
Respiratory guidelines 1996-04-01
TLV-TWA 1996-09-01
TLV comments 1996-09-01
Carcinogenicity 2003-06-24
OSHA hazcom 2003-06-24
Bibliography 2005-03-14
Sampling/analysis 2005-03-14
Flash point 2006-10-04
LFL/LEL 2006-10-04
UFL/UEL 2006-10-04

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