Substance fact sheet
The background information page contains information and concepts that will be useful in understanding some of the issues surrounding the NPI. It is strongly recommended that you read this before reading the information presented below.
For an explanation of some of the terms used in this page, see the Glossary
| Substance name | Methyl isobutyl ketone |
| CASR number | 108-10-1 |
| Molecular formula | C6H12O |
| Synonyms | Hexone; 4-Methyl-2-pentanone; Isobutyl methyl ketone; MIBK; 4-Methylpentan-2-one; MIK; 2-methyl-4-pentanone; Isohexanone |
Physical and chemical properties Physical properties: Methyl isobutyl ketone is a colourless liquid with a faint odour like camphor. Melting Point (°C): -84.7 Boiling Point (°C): 117.4; Vapour Density: 3.5 Specific Gravity: 0.7978 Chemical properties: |
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Common uses Methyl isobutyl ketone is used as a solvent for manufacturing: paints, rubbers, pharmaceuticals, chemicals and machinery. It is used in the semiconductor industry and the fragrance and flavor industry. It is used as a dry cleaning agent. It has been used as a pesticide. Methyl isobutyl ketone is also used in uranium extraction. |
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Sources of emissions Point sources The primary sources of methyl isobutyl ketone are the industries that manufacture it or use it in production. Some of the industries that use it in production are chemical industry, rubber manufacturers, pharmaceutical industry, the semiconductor industry, manufacturers of millwork, veneer and plywood and the manufacturers of paints, varnishes and lacquers. Diffuse sources, and point sources included in aggregated emissions data Other possible emitters of methyl isobutyl ketone are commercial and household painting and paint, varnish and lacquer removal, dry cleaners and consumer products containing methyl isobutyl ketone. Natural sources Methyl isobutyl ketone is found in oranges, grapes, and in vinegar. Mobile sources There are no known sources of mobile emissions of methyl isobutyl ketone. Consumer products which may contain Methyl isobutyl ketone Aerosol paints, architectural coatings, automobile and machinery paints and primers, household hard surface cleaners, household dyes and tints, Insecticides for yard and garden, laundry starches, lubricating greases and oils, automotive chemicals, paints, varnish and paint and varnish removers and thinners, pet flea and tick products, shoe polish, interior clear finishes, undercoats, and primers, and wood office furniture. |
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Health effects How might I be exposed to Methyl isobutyl ketone? Workers in the industries that use or produce methyl isobutyl ketone are at risk of exposure. Consumers can be exposed to methyl isobutyl ketone by exposure to air from production and processing facilities using methyl isobutyl ketone. Consumers may also be exposed to methyl isobutyl ketone when using consumer products containing methyl isobutyl ketone, especially if there is not good ventilation. Because methyl isobutyl ketone is used in many consumer products , short-term indoor concentrations may be elevated above the levels considered safe for workers. By what pathways might Methyl isobutyl ketone enter my body? Methyl isobutyl ketone will enter the body if we breathe in contaminated air, or consume food or water that has been contaminated. It can also pass through the skin. Relative health hazard On a health hazard spectrum of 0 - 3 Methyl isobutyl ketone registers 0.7. A score of 3 represents a very high hazard to health, 2 represents a medium hazard and 1 is harmful to health. Factors that are taken into account to obtain this ranking include the extent of the material's toxic or poisonous nature and/or its lack of toxicity, and the evaluation of its tendency to cause, or not cause cancer and/or birth defects. It does not take into account exposure to the substance. Human exposure is reflected in the NPI rank given to this substance (see comparative data below). A substance that scores highly as a health hazard is arsenic at 2.3 and one of the lowest scores is ammonia at 1.0.  Health guidelines Worksafe Australia: For methyl isobutyl ketone, it is allowable for workers to be exposed to concentrations of 50 parts per million over an eight hour workshift. See the Additional Information page for current health information. The Australian NOHSC National Exposure Standards Database link is probably the most useful source of information. Note that the emissions data in the NPI database is not directly comparable with these guidelines. What effect might Methyl isobutyl ketone have on my health? Breathing methyl isobutyl ketone for short periods of time (i.e. painting in a poorly ventilated area) can affect the nervous system. The effects may be headaches, dizziness, narcosis (acts like a narcotic), nausea, numbness in the fingers and toes, and (if the exposure is prolonged) unconsciousness, and even death. Methyl isobutyl ketone vapour irritates the eyes, nose, and throat. Prolonged contact with the skin will cause irritation. |
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Environmental effects Environmental Fate Methyl isobutyl ketone quickly evaporates to a gas if released as a liquid. It dissolves when mixed with water. It evaporates from both water and soil when exposed to air. It will quickly break down in the air into acetone, formaldehyde, and 2-methylpropanal. In the soil and water bacteria will break it down. Environmental Transport Industrial emissions of methyl isobutyl ketone can produce elevated, but still low level concentrations in the atmosphere around the source. Because of its short life expectancy in the atmosphere methyl isobutyl ketone is expected to be confined to the local area within which it is emitted. Since it does not bind to soil well, methyl isobutyl ketone that makes its way into the ground may move through the ground and enter groundwater (bore water). Relative hazard to the environment On an environmental spectrum of 0 - 3 Methyl isobutyl ketone registers 1.8. A score of 3 represents a very high hazard to the environment and 0 a negligible hazard. Factors that are taken into account to obtain this ranking include the extent of the material's toxic or poisonous nature and/or its lack of toxicity, and the measure of its ability to remain active in the environment and whether it accumulates in living organisms. It does not take into exposure to the substance. Environmental exposure is reflected in the NPI rank for this substance (see comparative data below). A substance that scores highly as an environmental hazard is oxides of nitrogen at 3.0 and one of the lower scores is carbon monoxide at 0.8.  Environmental guidelines See the Additional Information page for current environmental guidelines. No national guidelines. What effect might Methyl isobutyl ketone have on the environment? It has slight acute (short-term) toxicity on aquatic life and high toxicity to birds. It has slight chronic (long-term) toxicity to aquatic life. Chronic and acute effects on plants or land animals have not been determined. Methyl isobutyl ketone is not expected to bioaccumulate. |
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Comparative data NPI Rank Approximately 400 substances were considered for inclusion on the NPI reporting list. A risk ranking was given based on health and environmental hazard identification and human and environmental exposure to the substance. Some substances were grouped together at the same rank with 208 ranks in total. Methyl isobutyl ketone was ranked as 28 out of the 208 ranks. Total hazard score (human health + environmental criteria) = 2.5.  |
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Sources of information used in preparing this fact sheet
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