Acetic acid, aka ethanoic acid and E260, is the second simplest carboxylic acid. When it is pure acetic acid, it is called glacial acetic acid. Its formula is CH3COOH, and it has a distinctive pungent smell and taste. It is a clear, colourless liquid. [1,2,3,4,5]
Acetic acid is the main ingredient in vinegar; the condiment contains between 3-9% acetic acid. The acid is also used as a food additive (aka E260), for flavour and as an acidity regulator. It is used to make polyvinyl and cellulose acetate. Large quantities of the acid are used to make ink for dyes, pharmaceuticals, photographic chemicals, rubber and plastics. It is also used in some household cleaning products.
Routes of Exposure 
Routes of exposure include inhalation and skin/eye contact.
Acetic acid poisoning affects a range of systems, including the integumentary and respiratory systems.
Acute Effects 
Severity of symptoms depend on the level and type of exposure.
Inhalation of the acid may result in irritation of the respiratory tract, resulting in coughing, mucous membrane damage and choking. It could also cause dizziness, headaches, weakness, nausea and pulmonary oedema. It may cause transient loss of voice. Ingestion of the acid may result in burns on the mucous membranes of the throat, mouth and oesophagus. It may also cause nausea, vomiting, diarrhoea, shock (including clammy skin and shallow breathing), convulsions or a coma. Skin and eye contact could result in pain and burns, which may heal at a slow pace. Direct eye contact with the acid may result in lachrymation, burns and photophobia. Severe burns could result in permanent damage, but milder burns tend to heal quickly.
Chronic Effects 
Chronic exposure to acetic acid is toxic to multiple body systems. Long term exposure to the acid can result in erosion of the teeth, ulcerative changes in the mouth, bronchial irritation (including a cough and frequent bouts of bronchial pneumonia), and gastrointestinal disturbances. Chronic exposure to the acid can also result in systemic breathing problems, blackening of the skin and teeth, nausea, vomiting, diarrhoea, and chronic respiratory inflammation.
First Aid Measures 
Ingestion: DO NOT induce vomiting. Move patient into recovery position. If the person is conscious (and not showing any signs of drowsiness), then you can give them water to rinse their mouth. Contact a medical professional immediately.
- Skin contact: Remove all contaminated clothing, footwear and accessories. Do not re-wear clothing until it has been thoroughly decontaminated. Immediately rinse affected areas with plenty of soap and water. Contact a doctor immediately.
- Eye contact: Flush eyes (including under the eyelids), with fresh running water for at least 15 minutes. Removal of contact lenses should only be done by skilled personnel. Contact a medical professional immediately.
- Inhalation: If the person inhales fumes, combustion products or aerosols, remove them from the contaminated site. Prostheses, such as false teeth, should be removed prior to first aid procedures, as they may block airways. Perform CPR if you are qualified and if the patient is unconscious and not breathing. Use a one-way valve and mask if possible. Immediately contact a medical professional.
- General: Never administer anything by mouth to an unconscious, exposed person.
Exposure Controls/Personal Protection 
Engineering controls: Emergency eyewash fountains and quick-drench areas should be accessible in the immediate area of the potential exposure. Ensure there is adequate ventilation.
- Personal protection: Safety glasses with side shields or chemical goggles, protective and dustproof clothing, gloves (do not wear polyethylene gloves; wear elbow length PVC gloves), a P.V.C apron and an appropriate mask or dusk respirator. Do not wear contact lenses as they could absorb chemicals in the air. Wear impervious shoes. Other protection could overalls. For specifications regarding other PPE, follow the guidelines set in your jurisdiction.
The National Institute for Occupational Safety and Health (NIOSH) has set a Time Weighted Average (TWA) concentration limit for acetic acid of 10ppm.
Australia Exposure Standards have set a TWA for acetic acid of 10ppm.