Properties and Health Effects

Summary
Exposure to 2-butanone occurs in the workplace or from using consumer products containing it. Mild irritations of the eyes, nose, and throat were seen in people who breathed 2-butanone.

What is 2-butanone?
2-Butanone is a manufactured chemical but it is also present in the environment from natural sources. It is a colorless liquid with a sharp, sweet odor. It is also known as methyl ethyl ketone (MEK). 2-Butanone is produced in large quantities. Nearly half of its use is in paints and other coatings because it will quickly evaporate into the air and it dissolves many substances. It is also used in glues and as a cleaning agent. 2-Butanone occurs as a natural product. It is made by some trees and found in some fruits and vegetables in small amounts. It is also released to the air from car and truck exhausts.

What happens to 2-butanone when it enters the environment?
2-Butanone enters the air during production, use and transport, and from hazardous waste sites. In air, one-half of it will break down from sunlight in 1 day or less. It dissolves in water and is broken down more slowly to a
simpler chemical form in about 2 weeks. It does not stick to soil and will travel through the soil to the groundwater. Some of the 2-butanone in soil or water will evaporate into the air. It does not deposit in the bottom of rivers or lakes. It is not expected to concentrate in fish or increase in the tissues of animals further up the food chain.

How might I be exposed to 2-butanone?
Breathing contaminated air from the production or use of paints, glues, coatings, or cleaning agents containing it. Breathing contaminated air near hazardous waste sites. Breathing cigarette smoke. Sniffing glues. Drinking contaminated water from wells near manufacturing or hazardous waste sites. Skin contact with the liquid during production or use.

How can 2-butanone affect my health?
The known health effects to people from exposure to 2-butanone are irritation of the nose, throat, skin, and eyes. No one has died from breathing 2-butanone alone. If 2-butanone is breathed along with other chemicals that damage health, it can increase the amount of damage that occurs.  Serious health effects in animals have been seen only at very high levels. When breathed, these effects included birth defects, loss of consciousness, and death. When swallowed, rats had nervous system effects including drooping eyelids and uncoordinated muscle movements. There was no damage to the ability to reproduce. Mice who breathed low levels for a short time showed temporary behavioral effects. Mild kidney damage was seen in animals that drank water with lower levels of 2-butanone for a short time. There are no long-term studies with animals either breathing or drinking 2-butanone.

How likely is 2-butanone to cause cancer?
The Department of Health and Human Services has not classified 2-butanone as to its human carcinogenicity. The International Agency for Research on Cancer and the U.S. Environmental Protection Agency (EPA) have also not classified 2-butanone as to its human carcinogenicity. Two studies of workers exposed to 2-butanone and other chemicals did not find an increase in cancer. No animal studies are available that examine the potential for 2 butanone to cause cancer.

Is there a medical test to show whether I’ve been exposed to 2-butanone?
Tests are available to measure 2-butanone or its breakdown products in blood, breath, and urine. These tests are
useful only to measure recent exposures because 2-butanone and its breakdown products leave the body rapidly. These tests are not usually performed at your doctor's office, but your doctor can take blood or urine samples and send them to a testing laboratory.

Has the federal government made recommendations to protect human health?
The U.S. EPA requires that discharges or spills into the environment of 5,000 pounds of more of 2-butanone be
reported. The Occupational Safety and Health Administration (OSHA) set an occupational exposure limit of 200 parts of 2-butanone per million parts of workplace air (200 ppm) for an 8-hour workday, 40-hour workweek. The American Conference of Governmental Industrial Hygienists (ACGIH) and the National Institute for Occupational Safety and Health (NIOSH) have established the same guidelines as OSHA for the workplace.

Glossary
Carcinogenicity: Ability to cause cancer.
Evaporate: To change into a vapor or a gas.
ppm: Parts per million.
Long-term: Lasting one year or longer.
Short time: Lasting 14 days or less.

References
Agency for Toxic Substances and Disease Registry (ATSDR). 1992. Toxicological profile for 2-butanone. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

Updated: September 1995