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 sulfuric acid. It describes how you might be exposed to this substance, how exposure might effect you and the environment, common uses, comparative data about sulfuric acid 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 sulfuric acid emissions in Australia.
Sulfuric acid is a corrosive chemical and can severely burn the skin and eyes. It may cause third degree burns and blindness on contact. Exposure to sulfuric acid mist can irritate the eyes, nose, throat and lungs, and at higher levels can cause a buildup of fluid in the lungs (pulmonary oedema). Asthmatics are particularly sensitive to the pulmonary irritation. Repeated exposures may cause permanent damage to the lungs and teeth. The International Agency for Research on Cancer has classified 'occupational exposures to strong-inorganic-acid mists containing sulfuric acid' as carcinogenic to humans.
Sulfuric acid will enter the body if we breathe in contaminated air. While it is not absorbed through the skin, skin contact with strong concentrations may cause serious burns.
Consumers are most likely to be exposed to sulfuric acid when using products containing the substance (e.g. some cleaning products, or car batteries). Workers in the industries that use or produce sulfuric acid are at risk of exposure. Consumers can also be exposed to sulfuric acid by exposure to air contaminated by sulfur dioxide emissions.
See Sources for more information.
Worksafe Australia: The eight hour time weighted average (TWA) exposure limit is 1 mg/m³, with a short term exposure limit (STEL) of 3 mg/m³. Worksafe Australia reports this product causes severe burns.
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.
Sulfuric acid will exist as particles or droplets in the air if released to the atmosphere. It dissolves when mixed with water. It has moderate acute (short-term) toxicity on aquatic life. Sulfuric acid is very corrosive and would badly burn any plants, birds or land animals exposed to it. It has moderate chronic (long-term) toxicity to aquatic life. Chronic effects on plants, birds or land animals have not been determined. Small quantities of sulfuric acid will be neutralised by the natural alkalinity in aquatic systems. Larger quantities may lower the pH for extended periods of time.
Industrial emissions of sulfuric acid can produce elevated concentrations in the atmosphere. Sulfuric acid will exist as particles or droplets which may dissolve in clouds, fog, rain, dew, or snow, resulting in very dilute acid solutions. In clouds and moist air it will travel along the air currents until it is deposited as wet acid deposition (acid rain, acid fog, etc). In waterways it readily mixes with the water.
Sulfuric acid enters the air during production, use and transporting it. In the air it will react with other chemicals present (ammonia, magnesium, calcium) to form salts, which neutralise the acid. The acid particles dissolve in clouds, fog, rain, or snow, resulting in very dilute acid solutions. This may impact the environment as wet acid deposition ('acid rain').
Australian Water Quality Guidelines for Fresh and Marine Waters (ANZECC, 1992):
No guideline specifically for sulfuric acid, although the guideline value for pH (a measure of the acidity or alkalinity of water) is in the range 6.5 to 9.0 for fresh water.
Note that the emissions data in the NPI database is not directly comparable with these guidelines.
Sulfuric acid is the world's largest volume industrial chemical. The main use is in the production of phosphate fertilizers. It is used to manufacture explosives, other acids, dyes, glue, wood preservatives, and automobile batteries. It is used in the purification of petroleum, the pickling of metal, copper smelting, electroplating, metal work, and the production of rayon and film.
The primary sources of sulfuric acid emissions are the industries that manufacture it or use it in production. Some of the industries that use it in production are the metal smelters, phosphate fertilizer producers, oil refiners, the chemical industry, battery manufacturers, manufacturers or fabricated metal products, manufacturers of electronic components, and manufacturers of measuring and controlling devices. These are emissions to the air unless there is a spill to water or land. Sulfuric acid spilt to land or water may result in emissions of the acid to air.
Other possible emitters of sulfuric acid are home and larger pool treatment, the disposal of automobile batteries, electroplating facilities, electronics, semiconductor and circuit board production, potato growers, and water and waste water treatment. These emissions may be to the soil, water, or air. Sulfuric acid may be also produced as a result of sulfur dioxide reacting with other chemicals in the air.
Sulfuric acid occurs naturally in volcanic gasses.
Although sulfuric acid is not found in motor vehicle exhaust, it may be produced by the reaction of sulfur dioxide in the exhaust with other chemicals.
Hard surface cleaners, metal cleaners, pool chemicals, car, motorcycle, truck and boat batteries.
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.
Sulfuric acid was ranked as 8 out of 400. The total hazard score taking into account both human health and environmental criteria is 3.6.
On a health hazard rating of 0 - 3 sulfuric acid registers 2.3. 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 sulfuric acid registers 1.3. 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 | Sulfuric acid |
| CASR number | 7664-93-9 |
| Molecular formula | H2SO4 |
| Synonyms | Oil of vitriol; Dipping Acid; Vitriol Brown Oil; Sulfuric; Acid mist; Hydrogen sulfate; Sulfur Acid; Sulphuric Acid; Sulphine acid; battery acid |
| Physical properties: Sulfuric acid is a clear, colourless, oily liquid. Melting Point (°C) 10.35 Boiling Point (°C) 315-338 Vapour Density 3.4 Specific Gravity 1.84 |
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| Chemical properties: Sulfuric acid is very reactive and corrosive. It is soluble in water and ethyl alcohol. Its strong reactivity may ignite organic material (light paper, or other combustible materials) if mixed together. |
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There is more information that may be useful in understanding some of the issues surrounding the NPI.