2023-03-10

Sulfuric acid is a highly corrosive strong mineral acid with the molecular formula H2SO4. It is a colourless to slightly yellow viscous liquid which is soluble in water at all concentrations. Sometimes, it may be dark brown as it gets dyed during industrial production process in order to alert people to its hazards. Sulfuric acid is a diprotic acid which may show different properties depending upon its concentration. Its corrosiveness on metals, stones, skin, eyes and flesh or other materials can be mainly ascribed to its strong acidic nature and, if concentrated, strong dehydrating and oxidising properties. [1]

Uses [2]

The main use of sulfuric acid is in the production of phosphate fertilisers. It is also 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.

In the Environment [2,3]

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. Sulfuric acid is removed from the air in rain and contributes to the formation of acid rain.

Sources and Routes of Exposure [2,4]

Sources of Exposure

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 fertiliser 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 sulphur dioxide reacting with other chemicals in the air.

Routes of Exposure

The major routes of exposure to sulfuric acid are via inhalation of contaminated air, dermal or ocular exposure and ingestion. While it is not absorbed through the skin, contact of the skin and eyes with strong concentrations may cause serious burns.

Health Effects [2,4,5]

Acute Effects

Sulfuric acid causes irritation to the eyes, skin, nose, throat; pulmonary oedema, bronchitis; emphysema; conjunctivitis; stomatis; dental erosion; eye, skin burns; dermatitis. The substance is very corrosive to the eyes, the skin, and the respiratory tract and attacks the enamel of the teeth. Inhalation may result in a burning sensation, sore throat, cough, laboured breathing, shortness of breath and lung oedema. Symptoms may be delayed. Skin contact may result in redness, pain, blisters, serious skin burns. Eye contact may result in redness, pain and severe deep burns. Corrosive on ingestion and may result in abdominal pain, burning sensation, shock or collapse.

Chronic Effects

Lungs may be affected by repeated or prolonged exposure to an aerosol of sulfuric acid. There is a risk of tooth erosion upon repeated or prolonged exposure to an aerosol of this substance.

Carcinogencity

The International Agency for Research on Cancer has classified ‘occupational exposures to strong-inorganic-acid mists containing sulfuric acid’ as carcinogenic to humans.

Safety [6]

First Aid Measures

Ingestion:

• If swallowed do NOT induce vomiting.
• If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain open airway and prevent aspiration.
• Avoid giving milk or oils.
• Avoid giving alcohol.
• If spontaneous vomiting appears imminent or occurs, hold patient’s head down, lower than their hips to help avoid possible aspiration of vomit.

Eye Contact:

• Immediately hold eyelids apart and flush the eye continuously with running water.
• Ensure complete irrigation of the eye by keeping eyelids apart and away from eye and moving the eyelids by occasionally lifting the upper and lower lids.

Skin Contact:

• Immediately remove all contaminated clothing, including footwear.
• Flush skin and hair with running water (and soap if available).

Inhalation:

• If fumes or combustion products are inhaled remove from contaminated area.
• Lay patient down. Keep warm and rested.

Exposure Controls and Personal Protection

Engineering Controls

For flammable liquids and flammable gases, local exhaust ventilation or a process enclosure ventilation system may be required. Ventilation equipment should be explosion-resistant.

Respirator

Type AENO-P Filter of sufficient capacity should be used

Personal Protective Equipment

• Eyes: Safety glasses with side shields and chemical goggles.
• Hands: Chemical protective gloves, such as PVC should be worn. Suitability and durability of glove type is dependent on usage. Factors such as frequency and duration of contact and chemical resistance of glove material should be considered.
• Feet: Safety footwear or safety gumboots should be worn.
• Other safety equipment advised include overalls and PVC Apron.
• Some plastic personal protective equipment (PPE) (e.g. gloves, aprons, overshoes) are not recommended as they may produce static electricity.
• For large scale or continuous use wear tight-weave non-static clothing (no metallic fasteners, cuffs or pockets), non sparking safety footwear.

Regulation

United States [7]

Exposure Limit	Limit Values	HE Code	Health Factors and Target Organs
OSHA Permissible Exposure Limit (PEL) – General Industry	1 mg/m3 TWA	HE10	Lung changes
		HE11	Cough
OSHA PEL -Construction Industry	1 mg/m3 TWA	HE10	Lung changes
		HE11	Cough
OSHA PEL – Shipyard Employment	1 mg/m3 TWA	HE10	Lung changes
		HE11	Cough
National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL)	1 mg/m3 TWA	HE3	Dental erosion
		HE10	Pulmonary fibrosis, bronchiectasis, and emphysema
		HE11	Pulmonary oedema
		HE14	Respiratory irritation, cough
American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV)	0.2 mg/m3 TWA         (thoracic particulate mass)         A2 (when contained in strong inorganic acidmists)	HE3	Dental erosion
		HE10	Pulmonary fibrosis, bronchiectasis, and emphysema
		HE14	Marked eye, nose, throat, bronchial, and skin irritation
CAL/OSHAPELs	0.1 mg/m3 TWA        3 mg/m3 STEL		Irritation of the upper and lower respiratory tract

Australia [2]

Safe Work Australia: Safe Work Australia has set an eight-hour time weighted average (TWA) exposure limit of 1 mg/m3, with a short term exposure limit (STEL) of 3 mg/m3.

References

http://en.wikipedia.org/wiki/Sulfuric_acid

http://www.npi.gov.au/substances/sulfuric-acid/index.html

http://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=255&tid=47

http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1194947358719

http://www-group.slac.stanford.edu/esh/eshmanual/references/hazmatguidesulfuricacid.pdf

http://www.wattylindustrial.com.au/documents/industrial/msds/Wattyl%20Acid%20Cat%20Part%20B%205072-28%20MSDS.pdf

https://www.osha.gov/dts/chemicalsampling/data/CH_268700.html