* Benzene causes cells not to function correctly. For example, it can cause bone marrow not to produce enough red blood cells, which can lead to anaemia. Also, it can damage the immune system by changing blood levels of antibodies and causing the loss of white blood cells.

* The seriousness of poisoning caused by benzene depends on the amount, route, and length of time of exposure, as well as the age and pre-existing medical condition of the exposed person.

Immediate signs and symptoms of exposure to benzene

* People who breathe in high levels of benzene may develop the following signs and symptoms within minutes to several hours:

* Drowsiness

* Dizziness

* Rapid or irregular heartbeat

* Headaches

* Tremors

* Confusion

* Unconsciousness

* Death (at very high levels)

* Eating foods or drinking beverages containing high levels of benzene can cause the following symptoms within minutes to several hours:

* Vomiting

* Irritation of the stomach

* Dizziness

* Sleepiness

* Convulsions

* Rapid or irregular heartbeat

* Death (at very high levels)

* If a person vomits because of swallowing foods or beverages containing benzene, the vomit could be sucked into the lungs and cause breathing problems and coughing.

* Direct exposure of the eyes, skin, or lungs to benzene can cause tissue injury and irritation.

* Showing these signs and symptoms does not necessarily mean that a person has been exposed to benzene.

Long-term health effects of exposure to benzene

* The major effect of benzene from long-term exposure is on the blood. (Long-term exposure means exposure of a year or more.) Benzene causes harmful effects on the bone marrow and can cause a decrease in red blood cells, leading to anaemia. It can also cause excessive bleeding and can affect the immune system, increasing the chance for infection.

* Some women who breathed high levels of benzene for many months had irregular menstrual periods and a decrease in the size of their ovaries. It is not known whether benzene exposure affects the developing foetus in pregnant women or fertility in men.

* Animal studies have shown low birth weights, delayed bone formation, and bone marrow damage when pregnant animals inhaled benzene.

* The Department of Health and Human Services has determined that benzene causes cancer in humans. Long-term exposure to high levels of benzene in the air can cause leukaemia, cancer of the blood-forming organs.

How you can protect yourself, and what to do if you are exposed to benzene

* First, if the benzene was released into the air, get fresh air by leaving the area where the benzene was released. Moving to an area with fresh air is a good way to reduce the possibility of death from exposure to benzene in the air.

* If the benzene release was outside, move away from the area where the benzene was released.

* If the benzene release was indoors, get out of the building.

* If you are near a release of benzene, emergency co-ordinators may tell you to either evacuate the area or to “shelter in place” inside a building to avoid being exposed to the chemical.

* If you think you may have been exposed to benzene, you should remove your clothing, rapidly wash your entire body with soap and water, and get medical care as quickly as possible.

* Any clothing that has to be pulled over the head should be cut off the body instead of pulled over the head.

* If you are helping other people remove their clothing, try to avoid touching any contaminated areas, and remove the clothing as quickly as possible.

* If your eyes are burning or your vision is blurred, rinse your eyes with plain water for 10 to 15 minutes. If you wear contacts, remove them after washing your hands and put them with the contaminated clothing. Do not put the contacts back in your eyes (even if they are not disposable contacts). If you wear eyeglasses, wash them with soap and water. You can put your eyeglasses back on after you wash them.

— Centers for Disease Control