Air toxics and indoor air quality in Australia

State of knowledge report
Environment Australia, 2001
ISBN 0 6425 4739 4

Part C: Factsheets (continued)

Methyl ethyl ketone

Substance name: Methyl ethyl ketone
CASR number: 78-93-3
Molecular formula: C4H8O
Synonyms: 2-Butanone; MEK; ethyl methyl ketone; butanone; methyl acetone; butan-2-one;

Physical and chemical properties

Methyl ethyl ketone is a colourless liquid with a faint sweet odour.

Melting point: -86.3°C
Boiling point: 79.6°C
Vapour density: 2.5
Specific gravity: 0.805
Flashpoint: -6°C

Methyl ethyl ketone is a flammable liquid. It is partially soluble in water, and soluble in most other organic solvents. It will float on water while it rapidly dissolves in it.

Common uses

Methyl ethyl ketone is used as a solvent for lacquers, adhesives; for cleaning materials to be electroplated; for degreasing; in rubber and rubber cement, printing inks, paints, wood stains, varnishes and paint removers and in cleaning solutions; as a catalyst; and as a carrier.

Sources of emissions

Point sources

The primary sources of methyl ethyl ketone emissions are the industries that either manufacture it or use it in production, such as the chemical industry, rubber manufacturers, the pharmaceutical industry, the semiconductor industry, heavy equipment manufacturing, manufacturers of millwork, veneer and plywood, and manufacturers of paints, inks, varnishes and lacquers. These are emissions to the air unless there is a spill.

Diffuse sources, and point sources included in aggregated emissions data

Other possible emitters of methyl ethyl ketone are commercial and household painting and paint, varnish and lacquer removal, tobacco smoke, and consumer products containing methyl ethyl ketone. These are emissions to the air unless there is a spill.

Natural sources

Methyl ethyl ketone occurs naturally in volcanoes, forest fires and bushfires, products of biological degradation, and in some foods.

Mobile sources

Methyl ethyl ketone is found in motor vehicle exhaust.

Consumer products that may contain methyl ethyl ketone

Aerosol paints, architectural coatings, automobile and machinery paints and primers, household hard surface cleaners, household dyes and tints, inks, insecticides for yard and garden, laundry starches, lubricating greases and oils, automotive chemicals, markers, nail polish and polish remover, paints and varnish, paint and varnish removers and thinners, shoe polish, interior clear finishes, undercoats, and primers, waterproofing compounds, particleboard, and wood office furniture.

Health effects

How might I be exposed to methyl ethyl ketone?

Workers in the industries that use or produce methyl ethyl ketone are at risk of exposure. Consumers can be exposed to methyl ethyl ketone by exposure to air from production and processing facilities using methyl ethyl ketone, or by drinking water from contaminated bores. Consumers may also be exposed to methyl ethyl ketone when using consumer products containing the substance, especially if there is not good ventilation, or by skin contact. Smoking tobacco products and sniffing glues can also expose people to methyl ethyl ketone.

By what pathways might methyl ethyl ketone enter my body?

Methyl ethyl 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.

Health guidelines

National Occupational Health and Safety Commission (NOHSC):

What effect might methyl ethyl ketone have on my health?

Breathing methyl ethyl ketone for short periods of time (ie painting in a poorly ventilated area) can affect the nervous system. Effects include headaches, dizziness, fatigue, narcosis (acts like a narcotic), nausea, vomiting, and passing out. Methyl ethyl ketone vapour irritates the eyes, nose, and throat. Prolonged contact with the skin causes irritation. Contact with the eyes can permanently damage them. Repeated exposure may damage the nervous system and may affect the brain.

Environmental effects

Environmental fate

Methyl ethyl ketone enters the air during production, use and its transportation. In the air, sunlight breaks it down into other chemicals in one day or less. Methyl ethyl ketone dissolves when mixed with water. In water it is broken down into other chemicals in about two weeks. In soil and water, bacteria break it down. It does not deposit on the bottom of rivers or lakes.

Environmental transport

Industrial emissions of methyl ethyl 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 ethyl ketone is expected to be confined to the local area within which it is emitted. Since it does not bind to soil well, methyl ethyl ketone that makes its way into the ground may move through the ground and enter groundwater (bore water). Because methyl ethyl ketone is used in many consumer products, including tobacco smoke, short-term indoor concentrations may be elevated above the levels considered safe for workers.

Environmental guidelines

There are no national guidelines.

What effect might methyl ethyl ketone have on the environment?

Methyl ethyl ketone exists as a gas if released to the atmosphere and quickly reacts to form other chemicals. It dissolves when mixed with water. In water and soil, bacteria break it down. It has slight acute (short-term) and chronic (long-term) toxicity to aquatic life. Chronic and acute effects on plants, birds or land animals have not been determined. Methyl ethyl ketone is not expected to bioaccumulate.


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