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CHEMINFO Record Number: 602
CCOHS Chemical Name: Potassium formate

Formic acid, potassium salt
Formate de potassium

CAS Registry Number: 590-29-4
RTECS Number(s): LQ9625000
EU EINECS/ELINCS Number: 209-677-9
Chemical Family: Saturated aliphatic carboxylic acid salt / saturated aliphatic monocarboxylic acid salt / alkanoic acid salt / formate / potassium salt
Molecular Formula: C-H-K-O2
Structural Formula: H-CO2-.K+


Appearance and Odour:
Colourless crystals; deliquescent (absorbs moisture from the air and forms wet solid or solution) (8)

Odour Threshold:
Not available

Warning Properties:
Insufficient information available for evaluation.

Potassium formate is one of the soluble salts of formic acid. It has many similarities (properties and hazards) to other formates. This record contains the available information specific for potassium formate, supplemented with general information on formate salts which is applicable to potassium formate. It is available commercially in very pure form (more than 99% purity) (1) and as 50% and 70% solutions.(1,2)

Uses and Occurrences:
Used in fungicides and bactericides in agriculture (2); production of oxalates.(3)


Colourless deliquescent crystals. Probable COMBUSTIBLE DUST. May form explosive dust-air mixtures. Forms highly flammable hydrogen gas at temperatures above 167 deg C. Essentially non-toxic.


Effects of Short-Term (Acute) Exposure

No animal or human inhalation studies have been reported. It is expected that potassium formate causes only minor, reversible effects on the lungs. High concentrations of dust or mist (from solutions) can cause irritation of the upper respiratory tract.(4)

Skin Contact:
No human or animal information available. Solutions may cause skin irritation.(4)

Eye Contact:
No human or animal information available. Mists or solutions may cause eye irritation.(4) For dust, some tearing, blinking and mild, temporary pain may occur as the solid material is rinsed from the eye by tears.

Based on animal studies, potassium formate is very low in oral toxicity. Although no specific human information is available, information from related chemicals such as sodium formate, suggested small doses would probably not produce ill effects. Large doses (greater than 10 g) may cause mouth and esophageal irritation, stomach pain, cramps, vomiting, and collapse.(5) Ingestion is not a typical route of occupational exposure.

Effects of Long-Term (Chronic) Exposure

SKIN: Prolonged or repeated contact with solutions can probably cause redness, drying and cracking of the skin (dermatitis).


No animal or human information is 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:
No animal or human information is available.

Reproductive Toxicity:
No animal or human information is available.

No information is available.

Toxicologically Synergistic Materials:
No information available

Potential for Accumulation:
Probably does not accumulate. Most formates are rapidly broken down and eliminated from the body.


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

Skin Contact:
No health effects expected. If irritation does occur, flush with lukewarm, gently flowing water for 5 minutes or until the chemical is removed. If irritation persists, obtain medical advice.

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 the particle/dust does not dislodge, flush with lukewarm, gently flowing water for 5 minutes or until particle/dust is removed, while holding the eyelid(s) open. If irritation persists, obtain medical attention. DO NOT attempt to manually remove anything stuck to the eye(s).

No health effects expected. If irritation or discomfort occur, obtain medical advice immediately.

First Aid Comments:
All first aid procedures should be periodically reviewed by a physician familiar with the material and its conditions of use in the workplace.


Flash Point:
Not applicable. Potassium formate does not form a vapour.

Lower Flammable (Explosive) Limit (LFL/LEL):
Not available. Airborne dust can probably be ignited.(7)

Upper Flammable (Explosive) Limit (UFL/UEL):
Not well defined.

Autoignition (Ignition) Temperature:
Not available.

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

Sensitivity to Static Charge:
Under certain conditions, airborne dust of potassium formate can probably explode when ignited by an electrostatic spark, or other ignition source. No information is available for potassium formate, but explosion of the closely related sodium formate dust has occurred in laboratory tests.(7)

Combustion and Thermal Decomposition Products:
At temperatures above 167 deg C, potassium formate begins to decompose, releasing hydrogen (8); at about 360 deg C, it decomposes almost entirely to oxalate. Above and below 360 deg C, different decomposition products form.(3) Under fire conditions, carbon monoxide and carbon dioxide may be formed.(4)

Fire Hazard Summary:
Potassium format decomposes at temperatures above 167 deg C forming highly flammable hydrogen gas. Under certain conditions, a dust cloud of potassium formate can probably explode when ignited by a spark, flame or other ignition source. See reference 9 for a list of the main ignition sources of sufficient energy to cause a dust explosion. No specific information is available for potassium formate. However, explosion of the closely related sodium formate dust has occurred in laboratory tests.(7) When evaluating the explosion hazard of a specific process or sample of material, the important factors to consider include: particle size and shape, dust concentration, the nature of any impurities, oxygen concentration, humidity, and extent of containment.(9)

Extinguishing Media:
Use extinguishing media suitable for surrounding fire.

Fire Fighting Instructions:
Evacuate area and fight fire from a safe distance or a protected location. At temperature above 167 deg C, highly flammable hydrogen gas is formed.
Avoid generating dust to minimize risk of explosion. 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: 84.12

Conversion Factor:
Not applicable

Physical State: Solid
Melting Point: 167 deg C (333 deg F) (2,3)
Boiling Point: Not applicable. Decomposes above melting point.(2)
Relative Density (Specific Gravity): 1.91 (water = 1) (8)
Solubility in Water: Very soluble (331 g in 100 mL at 18 deg C) (2)
Solubility in Other Liquids: Soluble in ethanol; insoluble in diethyl ether (2)
Coefficient of Oil/Water Distribution (Partition Coefficient): Not available
pH Value: Practically neutral (8); 7.0-8.5 (1M solution at 25 deg C) (1)
Vapour Density: Not applicable
Vapour Pressure: Zero; does not form a vapour.
Saturation Vapour Concentration: Not applicable
Evaporation Rate: Not applicable
Critical Temperature: Not applicable


Normally stable.

Hazardous Polymerization:
Does 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 OXIDIZING AGENTS - risk of fire and explosion (4) STRONG ACIDS - may react vigorously and decompose potassium formate to produce formic acid vapours.

Hazardous Decomposition Products:
None known

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

Corrosivity to Metals:
Very mildly corrosive to most metals.(10)


LD50 (oral, rat): 5500 mg/kg (6)

No other relevant animal toxicity information was located.


Selected Bibliography:
(1) Fluka Chemika-BioChemika 1995/96. Fluka Chemie AG, 1995. p. 1228
(2) HSDB record for potassium formate. Date of last update: 9010
(3) Dancy, W.B. Potassium compounds. In: Kirk-Othmer encyclopedia of chemical technology. 3rd edition. Vol. 18. John Wiley & Sons, 1982. p. 938
(4) The Sigma-Aldrich Library of Chemical Safety Data. Edition II. Volume 2. Sigma-Aldrich Corporation, 1988. p. 1736A
(5) Solmann, T. Studies of chronic intoxications on albino rats : III. Acetic and formic acids. Journal of Pharmacology and Experimental Therapeutics. Vol. 16 (1921). p. 463-474
(6) Malorny G. Acute and chronic toxicity of formic acid and formates. Zeitschrift fur Ernaehrungswissenschaft, Vol. 9, no. 4 (1969). p. 332-339
(7) Field, P. Explosibility assessment of industrial powders and dusts. Building Research Establishment, 1983
(8) The Merck index: an encyclopedia of chemicals, drugs, and biologicals. 11th edition. Merck & Co., Inc., 1989. p. 1214
(9) Fire protection handbook. 17th edition. National Fire Protection Association, 1991. p. 2-332 to 2-333, 3-133 to 3-142
(10) Corrosion data survey : metals section. 6th edition. National Association of Corrosion Engineers, 1985. p. 100-101
(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: <>
(13) 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:

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: 1995-10-25

Revision Indicators:
Sampling 1996-01-01
EU class 1996-06-01
US transport 1996-06-01
Sampling 1996-06-01
Resistance of materials 1996-06-01
Bibliography 1996-06-01
EU number 1996-06-01
Respiratory guidelines 1996-06-01
Resistance of materials 1998-06-01
Bibliography 1998-06-01
Bibliography 2005-03-17
Sampling/analysis 2005-03-17
Bibliography 2005-03-24
Sampling/analysis 2005-03-24

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