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.
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
Sulfuric acid is a clear, colourless, oily liquid.
Melting Point: 10.35°C
Boiling Point: 315-338°C
Vapour Density: 3.4
Specific Gravity: 1.84
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.
The National Pollutant Inventory (NPI) holds data for all sources of Sulfuric acid 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.
Entering the body
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.
Workplace exposure standards
Safe Work Australia sets the workplace exposure standard for sulfuric acid through the workplace exposure standards for airborne contaminants:
- Maximum eight hour time weighted average (TWA): 1 mg/m3
- Maximum short term exposure limit (STEL): 3 mg/m3
These standards are only appropriate for use in workplaces and are not limited to any specific industry or operation. Make sure you understand how to interpret the standards before you use them.
Drinking water guidelines
There is no guideline for sulfuric acid in the Australian Drinking Water 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.
Entering the environment
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.
Where it ends up
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.
Sources of emissions
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.
Diffuse sources, and industry sources included in diffuse emissions data
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.
Sources used in preparing this information
- CalEPA Air Resources Board Toxic Air Contaminant Summary Sulfuric acid (accessed, May, 1999)
- ChemFinder WebServer Project (1995), Sulfuric acid (accessed, May, 1999)
- Chemical Industries Newsletter (July-August 1995) CEH Abstracts (accessed, May, 1999)
- Environmental Defense Fund (1998), Sulfuric acid: The Chemical Scorecard: (accessed, May, 1999)
- Environmental Health Center, a division of the National Safety Council, Environment Writer – Chemical Backgrounders Sulfuric acid (H2SO4) (July, 1997) (accessed, May, 1999)
- IARC: OCCUPATIONAL EXPOSURE TO MISTS AND VAPOURS FROM SULFURIC ACID AND OTHER STRONG INORGANIC ACIDS (accessed, July, 1999)
- National Environment Protection Council (1998a), National Environment Protection Measure for the National Pollutant Inventory (accessed, May, 1999)
- New Jersey Department of Health, Right to Know Program (1986), TRIFacts, Sulfuric Acid (accessed, May, 1999)
- Technical Advisory Panel (1999), Final Report to the National Environment Protection Council.
- University of California, Davis; School of Veterinary Medicine, Vermont SIRI MSDS Archive Site Sulfuric Acid (accessed, May, 1999)
- Worksafe Australia (1996), Hazardous Substance Sulphuric Acid (accessed, May, 1999)
- Worksafe Australia (1996), Hazardous Substance Sulphuric Acid (fuming) (accessed, May, 1999)
- Safe Work Australia, Workplace exposure standards for airborne contaminants, accessed February 2019.
- National Health and Medical Research Council (NHMRC), Australian Drinking Water Guidelines (2011) - Updated October 2017, accessed May 2018.