2-Hexanone is the organic compound with the formula C4H9COCH3. This colourless to pale yellow liquid has a sharp odour. It is a ketone and often known either as MBK (methyl butyl ketone) or 2-hexanone. It has moderate water solubility, and can evaporate easily into the air as a vapour. 
2-Hexanone was used in the past in paint and paint thinner, to make other chemical substances, and to dissolve oils and waxes. It is no longer made or used in the United States because it has harmful health effects. It is formed as a waste product resulting from industrial activities such as making wood pulp and producing gas from coal, and in oil shale operations.
Sources & Routes of Exposure
Sources of Exposure 
- Breathing contaminated air
- Drinking contaminated water
- Absorbing it through your skin if you touch liquid or soil that contains it
- Eating some foods that naturally contain low levels of 2-hexanone
- Using products manufactured before 1982 that contain 2-hexanone (such as paint thinners)
- Working in coal gasification, oil shale processing, or wood pulping operations
- Living near hazardous waste sites where it is found, or if you breathe the contaminated air.
Routes of Exposure 
Inhalation is the primary route of exposure to 2-hexanone; however, dermatologic exposure can lead to skin irritation and this absorption may contribute to chronic exposure and polyneuropathy. Ingestion has rarely been reported.
Health Effects [1,4]
- Contact with 2-hexanone can irritate the skin and eyes
- Inhalation can cause coughing and wheezing
- Exposure can cause headache, dizziness, light-headedness, and fainting
Prolonged inhalation of 2-hexanone can harm the nervous system. Workers who were exposed to 2-hexanone in the air for almost a year felt weakness, numbness, and tingling in the skin of the hands and feet. Similar effects were seen in different animals that ate or breathed high levels of 2-hexanone. Chronic exposure can also cause drying and cracking of the skin with redness and rash.
In animal studies, there was evidence that 2-hexanone damaged the male (testes) reproductive system and pregnant rats inhaled it did not gain as much weight during their pregnancy, had fewer babies, and had babies that were smaller and less active than the rats that were not exposed. It is unknown if breathing 2-hexanone affects human reproduction or causes birth defects.
The Department of Health and Human Services has not classified 2-hexanone as to human carcinogenicity. In addition, the International Agency for Research on Cancer and the Environmental Protection Agency (EPA) have not classified 2-hexanone as to human carcinogenicity. There is no information available on the potential carcinogenic effects of 2-hexanone in people or in experimental animals.
First Aid Measures
- Eye Contact: Check for and remove any contact lenses. Immediately flush eyes with running water for at least 15 minutes, keeping eyelids open. Cold water may be used. Do not use an eye ointment. Seek medical attention.
- Skin Contact: After contact with skin, wash immediately with plenty of water. Gently and thoroughly wash the contaminated skin with running water and non-abrasive soap. Be particularly careful to clean folds, crevices, creases and groin. Cold water may be used. Cover the irritated skin with an emollient. If irritation persists, seek medical attention. Wash contaminated clothing before reusing.
- Serious Skin Contact: Wash with a disinfectant soap and cover the contaminated skin with an anti-bacterial cream. Seek medical attention.
- Inhalation: Allow the victim to rest in a well ventilated area. Seek immediate medical attention.
- Serious Inhalation: Evacuate the victim to a safe area as soon as possible. Loosen tight clothing such as a collar, tie, belt or waistband. If breathing is difficult, administer oxygen. If the victim is not breathing, perform mouth-to-mouth resuscitation. Seek medical attention.
- Ingestion: Do not induce vomiting. Loosen tight clothing such as a collar, tie, belt or waistband. If the victim is not breathing, perform mouth-to-mouth resuscitation. Seek immediate medical attention.
Exposure Controls & Personal Protection
Exhaust ventilation or other engineering controls should be used to keep the airborne concentrations of vapours below their respective threshold limit value. Ensure that eyewash stations and safety showers are proximal to the work-station location.
Personal Protective Equipment
The following personal protective equipment is recommended when handling 2-hexanone:
- Splash goggles
- Lab coat
- Vapour respirator (be sure to use an approved/certified respirator or equivalent)
Personal Protection in Case of a Large Spill:
- Splash goggles
- Full suit
- Vapour respirator
- A self contained breathing apparatus should be used to avoid inhalation of the product.
- Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling this product.
- OSHA: The Occupational Safety and Health Administration has set a limit of 5 ppm (5 parts of 2-hexanone in 1 million parts of air) as an average exposure level to this chemical over a 40-hour work week.
- ACGIH: The American Conference of Governmental Industrial Hygienists has made the same recommendation.
- NIOSH: The National Institute for Occupational Safety and Health recommends an even lower limit, 1 ppm, as an average exposure during a 10-hour period.
- Safe Work Australia: Safe Work Australia has established a time weighted average concentration for 2-hexanone of 5ppm for an 8 hour workday.