Substance fact sheet
The National Pollutant Inventory (NPI) provides information on the types and amounts of pollutants being emitted in the Australian community.
This page provides facts about cobalt & compounds. It describes how you might be exposed to this substance, how exposure might effect you and the environment, common uses, comparative data about cobalt & compounds and its physical and chemical properties.
For more information about some of the terms used in this page, see the NPI glossary.
The National Pollutant Inventory (NPI) holds data for all sources of cobalt & compounds emissions in Australia.
Cobalt has both beneficial and harmful effects on humans. It is part of vitamin B-12, and may be used in the treatment of anaemia. Exposure to cobalt may cause lung effects, which include respiratory irritation, coughing, asthma, pulmonary oedema, and pneumonia. The International Agency for Research on Cancer classifies cobalt as a 'possible human carcinogen'. Exposure to cobalt salts may cause skin problems, and may damage the kidneys and cause lung damage. Cobalt can damage the heart, causing heart failure. Repeated exposures can cause scarring of the lungs (pulmonary fibrosis) which may not be noticed without a chest x-ray. This can be disabling or fatal.
Cobalt and cobalt products will enter the body if we breathe in contaminated air, drink contaminated water, or eat food containing cobalt. Small amounts occur naturally in food, water, and the air (from soil which has become dust). These small amounts are essential for good health.
Everyone is exposed to low levels of cobalt in the air, water and food we eat. Cobalt can also be absorbed through the skin. Workers in the industries that use or produce cobalt and its compounds (coal mining, hard metal industries, cobalt dye painting, and ore processing and chemical manufacturing) are at risk of higher exposure. Consumers can be exposed to cobalt and its compounds by exposure to air from production and processing facilities using cobalt and its compounds.
See Sources for more information.
Worksafe Australia:
For cobalt, eight hour time weighted average (TWA) exposure limit: 0.05 mg/m³.
For cobalt carbonyl (as cobalt), eight hour time weighted average (TWA) exposure limit: 0.1 mg/m³.
For cobalt hydrocarbonyl (as cobalt), eight hour time weighted average (TWA) exposure limit: 0.1 mg/m³
The Australian NOHSC National Exposure Standards Database link is probably the most useful source of information.
Note that the emissions data in the NPI database is not directly comparable with these guidelines.
Cobalt and its salts have high acute (short-term) toxicity on aquatic life. It also has high chronic (long-term) toxicity on aquatic life. There is not sufficient data to determine the acute or chronic toxicity of cobalt and its compounds on plants, birds or land animals. Cobalt and its compounds are highly persistent in water and the environment. Cobalt will bioaccumulate or concentrate in the tissues of fish.
Industrial emissions of cobalt and or cobalt compounds can produce elevated, but still low level concentrations in the atmosphere around the source. Because of its short life expectancy in the atmosphere cobalt and or cobalt compounds is expected to be confined to the local area within which it is emitted.
Cobalt and its compounds are expected to act like other particles in the atmosphere. The way they deposit in the local area will depend on the local wind and rain. They are expected to remain in the atmosphere from 5 to 15 days.
No national guidelines.
Cobalt is a metal that occurs naturally in many different forms. Small amounts of it are found in most rocks, soil, water, plants, and animals. Cobalt is a component of vitamin B-12, which is required for good health. The largest use of cobalt metal is to make alloys, which retain strength even when very hot. It is also used to help paint dry quickly. Cobalt is also used to make artificial body parts such as hip and knee joints. Cobalt carbonate is used in ceramics and as an animal feed supplement in trace amounts. Cobalt chloride is used as a humidity and water indicator, in electroplating, in the manufacture of vitamin B-12, as a fertilizer and feed additive in trace amounts. Cobalt oxide is used in pigments for ceramics and glass, in fast drying paints and varnishes, in semiconductors, in enamel coatings on steel, and again as an animal feed additive in trace amounts. Cobalt sulfate is used in electroplating, in batteries, as a drying agent in inks and varnishes, in enamels, and ceramics, and as a feed and fertilizer additive.
Cobalt is mainly emitted from sources where it is used in the production of steel and other alloys. It may be emitted to air, land or water from these sources. Automotive repair shops may be significant emitters (to air) of cobalt. It will also be emitted to air, land and water during the mining or refining of nickel, copper, silver, lead and iron.
Cobalt may be emitted to air, land or water from the manufacture, use or disposal of paints and varnishes. It may also be emitted to air, land or water from the manufacture, use or disposal of ceramic, inks, and enamels.
Cobalt is found in soil, dust, seawater, volcanic emissions, and smoke from forest and bush fires.
Small amounts of cobalt have been found in motor vehicle exhaust.
Consumer products containing cobalt and its compounds include: vitamin B-12, animal feeds and fertilisers, paints, varnish, enamels and ceramics. It is in metals used at high temperatures (e.g. some car parts).
Approximately 400 substances were considered for inclusion on the NPI reporting list. A ranking and total hazard score was given based on health and environmental hazards and human and environmental exposure to the substance.
Cobalt & compounds was ranked as 27 out of 400. The total hazard score taking into account both human health and environmental criteria is 3.0.
On a health hazard rating of 0 - 3 cobalt & compounds registers 1.0. A score of 3 represents a very high hazard to health, 2 represents a medium hazard and 1 is harmful to health.
On an environmental rating of 0 - 3 cobalt & compounds registers 2.0. A score of 3 represents a very high hazard to the environment and 0 a negligible hazard.
Factors taken into account to obtain this ranking and these scores include the extent of the material's toxic or poisonous nature and/or its lack of toxicity, and the measure of its ability to remain active in the environment and whether it accumulates in living organisms. It does not take into account exposure to the substance. Environmental exposure is reflected in the NPI rank for this substance (see comparative data below). A substance that scores highly as an environmental hazard is oxides of nitrogen at 3.0 and one of the lower scores is carbon monoxide at 0.8. A substance that scores highly as a health hazard is arsenic at 2.3 and one of the lowest scores is ammonia at 1.0.
| Substance name | Cobalt & compounds |
| CASR number | 7440-48-4 |
| Molecular formula | Co |
| Synonyms | Cobalt compounds: Cobalt carbonate, cobalt chloride, cobalt oxide, cobalt sulfate, cobalt nitrate |
| Physical properties: Cobalt metal is an odourless shiny, silvery metal, when first exposed to air. Melting Point (°C): Cobalt metal: about 1495 Boiling Point (°C:): Cobalt metal: 2870 to 3100 Specific Gravity: 8.92 |
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| Chemical properties: Pure cobalt does not dissolve in water, but will dissolve (or react) with acids. It will burn when exposed to heat. The fumes may be hazardous. Compounds that are not soluble in water are cobalt carbonate and cobalt oxide. Compounds that are soluble in water are cobalt nitrate and cobalt sulfate. |
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There is more information that may be useful in understanding some of the issues surrounding the NPI.