The following information has been extracted from our CHEMINFO database, which also contains hazard control and regulatory information. [More about...] [Sample Record]

Access the complete CHEMINFO database by contacting CCOHS Client Services.


CHEMINFO Record Number: 102
CCOHS Chemical Name: Trisodium phosphate

Sodium phosphate, tribasic
Tribasic sodium phosphate
Trisodium orthophosphate
Orthophosphate trisodique
Phosphoric acid, trisodium salt

Chemical Name French: Phosphate de sodium tribasique
Chemical Name Spanish: Fosfato sódico tribásico
CAS Registry Number: 7601-54-9
Other CAS Registry Number(s): 10101-89-0
RTECS Number(s): TC9575000 TC9490000
Chemical Family: Phosphoric acid salt / inorganic phosphate salt / inorganic sodium compound / sodium salt / trisodium salt
Molecular Formula: Na3-O4-P
Structural Formula: Na3.PO4 (anhydrous); Na3.PO4.12H2O (dodecahydrate)


Appearance and Odour:
Colourless or white, crystalline solid; odourless (decahydrate) (7)

Odour Threshold:

Warning Properties:
POOR - trisodium phosphate is odourless

Trisodium phosphate is available as the anhydrous salt (CAS 7601-54-9) and as the dodecahydrate (CAS 10101-89-0). Commercial dodecahydrate often contains excess sodium hydroxide (4(Na3PO4.12H2O).NaOH).(6) Trisodium phosphate can also exist as the hemihydrate (CAS 60593-58-0) and octahydrate (CAS 6053-59-1).

Uses and Occurrences:
Ingredient of soap powders and heavy-duty household, industrial and institutional detergents, cleaning agents and scouring powders; water softening agent; and elastomers. Used in the manufacture of paper and leather; metal cleaning; sugar purification; photographic developers; paint removers; as a dietary supplement; food additive; for the removal of insecticide sprays and as an inhibitor of fruit mold.(4,6,7)


Colourless or white, odourless crystalline solid. Will not burn. Can decompose at high temperatures forming irritating/toxic phosphorus oxides. Reacts with metals such as aluminum, zinc and galvanized iron to produce flammable hydrogen gas. CORROSIVE to the eyes and possibly the skin. May cause permanent eye injury.


Effects of Short-Term (Acute) Exposure

According to one report, irritation of the nose and throat was caused by exposure to 0.5 to 2.0 mg/m3 airborne dust for one hour. Irritation has also been reported after short exposures above 7-10 mg/m3.(1) High concentrations of dust or mists from concentration solutions are probably severely irritating or corrosive, based on pH. Trisodium phosphate does not form a vapour.

Skin Contact:
The solid material can probably cause moderate to severe irritation, especially if in contact with moisture or trapped under clothing. The degree of irritation of solutions varies depending on the concentration of the solution and the duration of contact. Water solutions with concentrations of 0.1% (pH 11.5) or greater may be corrosive or severely irritating.

Eye Contact:
Dusts and concentrated solutions can be corrosive. The factors which determine the extent and reversibility of the injury include the concentration of solution or the amount of trisodium phosphate which comes into contact with the eye and the duration of contact. Permanent damage (cloudiness of the cornea) has resulted from contact with trisodium phosphate solution in two case reports, one involving hot solution. Concentrations were not reported.(2) In another case report, injury occurred as a result of a splash of aqueous solution, but healed within 48 hours (concentration not reported).(3)

There are no reports of workers ingesting trisodium phosphate. It is used in very small quantities in food to increase alkalinity. Ingestion of a large amount would likely cause severe pain, burns to the mouth and the digestive tract, vomiting, and diarrhea. In severe cases, death could result. Ingestion is not a typical route of occupational exposure.

Effects of Long-Term (Chronic) Exposure

Drying, cracking and inflammation of the skin (dermatitis) can result from repeated or prolonged contact with the solid or solutions.


There is no human or animal information available.

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 no listing for this chemical.

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

Teratogenicity and Embryotoxicity:
There is no human or animal information available.

Reproductive Toxicity:
There is no human or animal information available.

There is no information available.

Toxicologically Synergistic Materials:
There is no information available.

Potential for Accumulation:
Trisodium phosphate is not expected to accumulate. Phosphates are normally present in the body. It is absorbed from the gastrointestinal tract and excess amounts are readily eliminated, mainly in the urine.(4)


Remove source of contamination or have victim move to fresh air. Obtain medical attention immediately.

Skin Contact:
Avoid direct contact with this chemical. Wear chemical protective gloves, if necessary. As quickly as possible, flush contaminated area with lukewarm, gently running water for at least 20 minutes or until the chemical is removed. Under running water, remove contaminated shoes, and leather goods (e.g., watchbands, belts). If irritation persists, repeat flushing. Obtain medical attention immediately. Discard contaminated shoes and leather goods.

Eye Contact:
Avoid direct contact with this chemical. Wear chemical protective gloves, if necessary. Immediately flush the contaminated eye(s) with lukewarm, gently flowing water for at least 20-30 minutes or until the chemical is removed, while holding the eyelid(s) open. Neutral saline solution may be used as soon as it is available. DO NOT INTERRUPT FLUSHING. Take care not to rinse contaminated water into the unaffected eye or onto the face. If irritation persists, repeat flushing. Quickly transport victim to an emergency care facility.

Never give anything by mouth if victim is rapidly losing consciousness, or is unconscious or convulsing. Have victim rinse mouth thoroughly with water. DO NOT INDUCE VOMITING. Have victim drink 240 to 300 mL (8 to 10 oz.) of water to dilute material in stomach. If milk is available, it may be administered AFTER the water has been given. If vomiting occurs naturally, rinse mouth and repeat administration of water. Obtain medical attention immediately.

First Aid Comments:
Provide general supportive measures (comfort, warmth, rest). Consult a doctor and/or the nearest Poison Control Centre for all exposures except minor instances of inhalation or skin contact.
All first aid procedures should be periodically reviewed by a doctor familiar with the material and its condition of use in the workplace


Flash Point:
Not combustible (does not burn).

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

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

Autoignition (Ignition) Temperature:
Not applicable

Sensitivity to Mechanical Impact:
Probably not sensitive. Stable material.

Sensitivity to Static Charge:
Not sensitive. The electrical conductivity of phosphates is probably high.

Combustion and Thermal Decomposition Products:
Phosphorus oxides (8)

Fire Hazard Summary:
Trisodium phosphate and its solutions do not burn or support combustion. Solutions can react with metals such as aluminum, zinc and galvanized iron to produce highly flammable hydrogen gas, that may explode if ignited. During a fire, irritating/toxic phosphorus oxides may be generated. Closed containers may explode in the heat of a fire.

Extinguishing Media:
This material does not burn. Extinguish fire using appropriate extinguishing media for the surrounding fire.

Fire Fighting Instructions:
Trisodium phosphate and its solutions do not burn or support combustion but solutions can react with metals to form highly flammable hydrogen gas.
Move containers from fire area if it can be done without risk. Otherwise, use water in flooding quantities as a spray or fog to keep fire-exposed containers cool and absorb heat. Water spray may also be used to knock down irritating/toxic combustion products which may be produced in a fire. Apply water from as far a distance as possible.
Trisodium phosphate decomposition products, such as phosphorous oxides, are hazardous to health. Do not enter without wearing specialized protective equipment suitable for the situation. Firefighter's normal protective equipment (Bunker Gear) will not provide adequate protection. Chemical resistant clothing (e.g. chemical splash suit and positive pressure self-contained breathing apparatus (MSHA/NIOSH approved or equivalent) may be necessary.


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


Molecular Weight: 163.94 (anhydrous); 380.13 (dodecahydrate)

Conversion Factor:
Not applicable

Physical State: Solid
Melting Point: 73.3-76.7 deg C (164-170 deg F) (dodecahydrate, with dehydration) (7)
Boiling Point: Does not boil.
Relative Density (Specific Gravity): 1.62 at 20 deg C (water=1) (7)
Solubility in Water: Very soluble (25.8 g/100 g water at 20 deg C) (dodecahydrate) (4,7)
Solubility in Other Liquids: Insoluble in ethanol, carbon disulfide (dodecahydrate) (4)
Coefficient of Oil/Water Distribution (Partition Coefficient): Not available
pH Value: 11.5 (0.1% solution); 11.7 (0.5% solution); 11.9 (1% solution) (9)
Vapour Density: Not applicable
Vapour Pressure: Does not form a vapour.
Saturation Vapour Concentration: Not applicable
Evaporation Rate: Not applicable
Critical Temperature: Not applicable


Normally stable.

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.

STRONG ACIDS - may react violently and cause splattering.(10)
METALS such as ALUMINUM, ZINC and GALVANIZED IRON - react with aqueous solutions to form flammable hydrogen gas.
MAGNESIUM - may react violently.

Hazardous Decomposition Products:

Conditions to Avoid:

Corrosivity to Metals:
Corrosive to aluminum, zinc and tin.(10) Not corrosive to cast iron, steel, stainless steel, nickel and its alloys at room temperature. Corrosive to gray cast iron at high temperatures.(11) May be corrosive to mild steel or brass, if wet.(8)

Stability and Reactivity Comments:
May react with air to form disodium phosphate and sodium carbonate.(10)


LD50 (oral, rat): 7400 mg/kg (5); 6500 mg/kg (20% solution) (1, unconfirmed)
LD50 (oral, rat): 4100 mg/kg (10% solution) (7, unconfirmed)

LD50 (dermal, rabbit): greater than 7940 mg/kg (1, unconfirmed)

Eye Irritation:

Trisodum phosphate is corrosive to the eyes.

Application of 0.1 g of undiluted anhydrous trisodium phosphate to rabbits caused corrosive injury in unwashed eyes (maximum average score: 53/110 at 48 hours; scored 50/110 at day 22). In washed eyes, the maximum average score was 22/110 at 24 hours, with complete recovery at day 22 (scored 0/110).(13 A corrosive effect was observed in rabbits 24 hours after application of 0.1 mL finely-ground trisodium phosphate. Only slight irritation resulted when 0.1 mL was placed in the eye for one minute, followed by washing. After 14 days, the eyes had regained normal appearance.(1, unconfirmed)

Skin Irritation:

Trisodium phosphate is expected to be corrosive to skin, based on pH. Minimal irritation was observed in one animal study and moderate irritation in another.

Application of 20 or 300 mg/kg anhydrous trisodium phosphate moistened with saline to rabbits, under cover for 24 hours, caused minimal irritation (scored 0.1/8.0 for 20 mg/kg; scored 0.2/8.0 for 300 mg/kg).(12) Moderate irritation was observed in rabbits when 0.5 g/mL of trisodium phosphate was held in continuous contact with intact and abraded skin for 24 hours.(1, unconfirmed)


Selected Bibliography:
(1) Trisodium phosphate. American Industrial Hygiene Association Journal. Vol. 43 (Oct. 1982). p. B-51-52
(2) Grant, W.M., et al. Toxicology of the eye. 4th ed. Charles C Thomas, 1993. p. 1474-1475
(3) McLaughlin, R. S Chemical burns of the human cornea. American Journal of Ophthalmology. Vol. 29 (Nov. 1946). p. 1355-1362
(4) HSDB record for trisodium phosphate. Last revision date: 94/12/21
(5) Smyth, Jr., H.F., et al. Range-finding toxicity data: list VII. American Industrial Hygiene Association Journal. (Sept.-Oct., 1969). p. 470-476
(6) Gard, D.R. Phosphoric acids and phosphates. In: Kirk-Othmer encyclopedia of chemical technology. 4th ed. Vol. 18. John Wiley and Sons, 1996. p. 669-718
(7) Workplace environmental exposure level guide for trisodium phosphate. American Industrial Hygiene Association, 1996
(8) Hazardous chemicals data book. 2nd ed. Noyes Data Corporation, 1986. p. 921-922
(9) Budavari, S., et al., eds. The Merck index: an encyclopedia of chemicals, drugs, and biologicals. 12th ed. Merck and Co., Inc., 1996. p. 1481
(10) Chemical safety sheets: working safely with hazardous chemicals. Kluwer Academic Publishers, 1991. p. 908
(11) Corrosion data survey. Metals section. 6th ed. National Association of Corrosion Engineers, 1985. p. 120-121
(12) Weiner, M., et al. Dermal toxicity/skin irritation studies on five inorganic phosphates. Journal of the American College of Toxicology. Vol. 1, no. 1, Part B (1990). p. 47-48
(13) Weiner, M., et al. Eye irritation studies on five inorganic phosphates. Journal of the American College of Toxicology. Vol. 1, no. 1, Part B (1990). p. 48-49
(14) 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: <>
(15) 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: <>
(16) 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: <>
(17) 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: 1996-07-24

Revision Indicators:
Synonyms 1996-09-01
TDG 2002-06-11
WHMIS disclosure list 2003-07-03
Carcinogenicity 2003-07-03
Bibliography 2003-09-12
Toxicological info 2003-09-12
Bibliography 2005-03-07
Sampling/analysis 2005-03-07
Bibliography 2005-03-12
Sampling/analysis 2005-03-12

©2007 Canadian  Centre  for  Occupational  Health  &  Safety  E-mail:  Fax: (905) 572-2206  Phone: (905) 572-2981  
Mail:  250  Main  Street  East,  Hamilton  Ontario  L8N  1H6