Guidance

Acetic acid: general information

Updated 26 November 2024

Overview

Acetic acid, also known as ethanoic acid, is a clear colourless liquid which has a pungent, vinegar-like odour. When it is pure (100% acetic acid) it is referred to as glacial acetic acid.

Uses of acetic acid

Acetic acid is the main component of vinegar, which contains 4 to 18% acetic acid. It is used as a food preservative and food additive (known as E260). Large quantities of acetic acid are used to make products such as ink for textile printing, dyes, photographic chemicals, pesticides, pharmaceuticals, rubber and plastics. It is also used in some household cleaning products to remove lime scale.

How acetic acid gets into the environment

Acetic acid can enter the environment from discharge and emissions from industries. The burning of plastics or rubber, and exhaust fumes from vehicles may also release acetic acid into the environment. When released into soil it evaporates into the air where it is broken down naturally by sunlight. Levels of acetic acid in the environment would be expected to be low.

Exposure to acetic acid

Humans naturally produce small amounts of acetic acid. It plays an important role in the metabolism of fats and carbohydrates in the body. Acetic acid is naturally present in some unprocessed foods including fruit and is present in some foods as an additive. There may also be exposure from the use of household products that contain acetic acid. Exposure to low levels of acetic acid in the environment, as part of a normal diet and from the correct use of household product would not be expected to cause adverse health effects.

Exposure to higher levels of acetic acid is more likely to occur in an occupational setting. However safe levels are enforced to protect employees who may be exposed to acetic acid at work. Such levels are below those that are thought to cause harmful effects.

How exposure to acetic acid could affect your health

The presence of acetic acid in the environment does not always lead to exposure. In order for it to cause any adverse health effects, you must come into contact with it. You may be exposed to acetic acid by breathing or ingesting it, or by skin contact with it. Following exposure to any chemical, the adverse health effects by which you may encounter depend on several factors, including the amount to which you are exposed (dose), the way you are exposed, the duration of exposure, the form of the chemical and if you were exposed to any other chemicals.

Low level exposure to acetic acid from the diet or from the correct use of household products that contain acetic acid would not be expected to cause adverse health effects.

Exposure to dilute solutions of acetic acid may cause irritation. Inhalation of acetic acid vapours may cause irritation of the eyes nose and throat and cough.

Exposure to more concentrated solutions of acetic acid (less than 25%) can cause corrosive damage.

Breathing vapours with high levels of acetic acid can cause irritation of eyes, nose and throat, cough, chest tightness, headache, fever and confusion. In serious cases damage to the airways, a fast heart rate and eye damage can occur. An accumulation of fluid in the lungs may occur and may take up 36 hours to develop.

Ingestion of higher concentrations causes immediate burning of the mouth and throat, breathing difficulty, drooling, difficulty swallowing, stomach pain and vomiting (there may be blood in the vomit).

Skin contact with strong acetic acid can cause pain, burns and ulcers. Contact with eyes causes pain, twitching of the eyelids, watering eyes, inflammation, sensitivity to light and burns.

Acetic acid and cancer

Acetic acid is not considered to be a cancer causing chemical.

Vulnerable people

People with breathing problems such as asthma may be more susceptible to the effects of inhaling acetic acid. This is because higher levels of acetic acid can cause irritation of airways leading to chest tightness, wheezing and breathlessness.

Pregnancy and the unborn child

Low level exposure to acetic acid from the diet or from the correct use of household products that contain acetic acid would not be expected to harm the unborn child.

There is limited information about overexposure to acetic acid during pregnancy. The irritant or corrosive tends to occur at the point of contact, for example, irritation to the skin or eyes. The absorption of acids into the body is generally low and therefore they do not cause effects in other parts of the body. Therefore, acetic acid is unlikely to have a direct effect on the unborn child. However, if the exposure acetic acid causes the mother to become unwell this may affect the health of the unborn child.

Children

If children breathe, ingest or touch acetic acid they will have similar effects to those seen in adults. They are not expected to be more sensitive to the effects of acetic acid.

Household cleaning products that contain acetic acid should be stored in an appropriate container and kept out of the reach of children.

What to do if you are exposed to acetic acid

Exposure to levels of acetic acid as found in household vinegar are not expected to cause harm.

If exposed to more concentrated acetic acid:

• you should remove yourself from the source of exposure
• if you have got acetic acid on your skin, remove soiled clothing (not over the head), wash the affected area with lukewarm water and soap for at least 10 to 15 minutes and seek medical advice
• if you have got acetic acid in your eyes, remove contact lenses, irrigate the affected eye with lukewarm water for at least 10 to 15 minutes and seek medical advice
• if you have inhaled or ingested acetic acid, seek medical advice

Additional sources of information

• UKTIS: best use of medicines in pregnancy
• NHS.UK information on acid and chemical burns
• FSA EU approved additives and E numbers

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