1,3-Butadiene


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Introduction

1,3-Butadiene is a chemical made from the processing of petroleum. It is the 36th highest volume chemical produced in the United States. It is a colorless gas with a mild gasoline-like odor. About 75% of the manufactured 1,3-butadiene is used to make synthetic rubber. Synthetic rubber is widely used for tires on cars and trucks. 1,3-Butadiene is also used to make plastics including acrylics. Small amounts are found in gasoline.

Structural diagram: National Institutes of Health


Fate & Transport

It quickly evaporates to the air as a gas from leaks during production, use, storage, transport, or disposal. It breaks down quickly in air by sunlight; in sunny weather, half of it breaks down in about 2 hours. When not sunny, it takes a few days for about half of it to break down in the air. It evaporates very quickly from water and soil. Since it evaporates so easily, it is not expected to be found in water or soil, but adequate tests are not available to measure the amounts. 1,3-Butadiene may be broken down by microorganisms in the soil. It is not expected to accumulate in fish.

Exposure Pathways

Breathing urban and suburban air, but these levels are generally very low except in polluted cities or near chemical, plastic, and rubber facilities that use it

Breathing contaminated workplace air where it is manufactured or used

Breathing contaminated air from car and truck exhaust, waste incineration, or wood fires

Breathing cigarette smoke

Drinking contaminated water near production or waste sites

Ingesting foods contained in plastic or rubber food containers, but levels are generally very low or not present at all

Skin contact with gasoline, but levels are low.

Health Effects

Most of the information on the health effects of 1,3-butadiene comes from studies where the exposure was from breathing contaminated air. Breathing very high levels of 1,3-butadiene for a short time can cause central nervous system damage, blurred vision, nausea, fatigue, headache, decreased blood pressure and pulse rate, and unconsciousness. There are no recorded cases of accidental exposures at high levels that caused death in humans, but this could occur. Breathing lower levels may cause irritation of the eyes, nose, and throat. Studies on workers who had longer exposures with lower levels have shown an increase in heart and lung damage, but these workers were also exposed to other chemicals. We don't know for sure which chemical (or chemicals) caused the effects. We also do not know what levels in the air will cause these effects in people when breathed over many years.

Animal studies show that breathing 1,3-butadiene during pregnancy can increase the number of birth defects. Other effects seen in animals that breathed low levels of 1,3-butadiene for one year include kidney and liver disease, and damaged lungs. Some of the animals died. There is no information on the effects of eating or drinking 1,3-butadiene. Skin contact with liquid 1,3-butadiene can cause irritation and frostbite.

The Department of Health and Human Services has determined that 1,3-butadiene may reasonably be anticipated to be a carcinogen. This is based on animal studies that found increases in a variety of tumor types from exposure to 1,3-butadiene. Studies on workers are inconclusive because the workers were exposed to other chemicals in addition to 1,3-butadiene.

There is currently no reliable medical test to determine whether you have been exposed to 1,3-butadiene. However, scientists are working on methods to measure it in the blood.

Information excerpted from:

Toxicological Profile for 1,3-Butadiene 1992

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