2,3-Benzofuran is a colorless, sweet-smelling, oily liquid made by processing coal into coal oil. It may also be formed during other uses of coal or oil. 2,3-Benzofuran is not used for any commercial purposes. Rather, the part of the coal oil that contains 2,3-benzofuran is made into a plastic called coumarone-indene resin. This resin resists corrosion and is used to make paints and varnishes. The resin also provides water resistance and is used in coatings on paper products and fabrics. It is used as an adhesive in food containers and is in some asphalt floor tiles. The resin has been approved for use in food packages and as a coating on citrus fruits. We do not know how often the resin is used or whether any 2,3-benzofuran in the coating or packaging gets into the food.

Structural diagram: National Institutes of Health

Fate & Transport

Very little is known about the stability or breakdown of 2,3-benzofuran or of the coumarone-indene resin. 2,3-Benzofuran may enter the air, water, and soil during its manufacture, use, or storage at hazardous waste sites. 2,3-Benzofuran may escape to the air near industrial or waste sites. It does not readily dissolve in water, but may enter the groundwater near manufacturing or hazardous waste sites. Limited information indicates that it will move into soil and sediment from water, but more information is needed. 2,3-Benzofuran is not expected to accumulate in fish or aquatic animals to any great extent. One study reported detecting 2,3-benzofuran in human breast milk, indicating that the mother had been exposed.

Exposure Pathways

Breathing contaminated air or touching the chemical in the workplace

Breathing contaminated air around manufacturing or hazardous waste sites

Eating foods from packaging material that contains coumarone-indene resins, but not much is known about how much gets into the food

Smoking cigarettes

Drinking contaminated water near manufacturing or hazardous waste sites

Drinking contaminated human breast milk.

Health Effects

Very little is known about the possible harmful effects of 2,3-benzofuran to human health. There are no studies that have looked at the effects in people from exposures to air, water, or food, or through skin contact. There are some studies in animals from exposures in food or water. Rats and mice that ingested high levels of 2,3-benzofuran over a short time had liver and kidney damage. Those exposed over a long time to moderate levels had liver, kidney, lung, and stomach damage. In one study, the ability of animals to reproduce was not affected. We do not know if people will experience health effects similar to those seen in animals.

The Department of Health and Human Services has not classified 2,3-benzofuran as to its human carcinogenicity. The International Agency for Research on Cancer and the Environmental Protection Agency (EPA) have also not classified 2,3-benzofuran as to its human carcinogenicity. Cancer of the kidneys, lungs, liver, or stomach was seen in rats and mice that ingested 2,3-benzofuran for long periods of time. There are no studies on 2,3-benzofuran's potential to cause cancer in people.

There is a test to measure 2,3-benzofuran in the blood or in breast milk. However, this test requires special equipment and is not usually available in your doctor's office. This test may only measure 2,3-benzofuran from a recent exposure. It is not known how long 2,3-benzofuran remains in your body after you have been exposed. The test can't tell whether you may develop any health problems from an exposure.

Information excerpted from:

Toxicological Profile for 2,3-Benzofuran 1992

Agency for Toxic Substances and Disease Registry
U.S. Dept. of Health and Human Services