Benzene is a clear, colorless liquid with a pleasant, sweet odor. It evaporates into air very quickly. The odor of benzene does not provide adequate warning of its hazard.

In this chapter, "benzene " means:

–

Liquid benzene, benzene vapor, and benzene in liquid mixtures and the vapor released by these liquids. The CAS Registry Number that identifies benzene is 71-43-2.

Synonyms for benzene include: Benzol, benzole, coal naphtha, cyclohexatriene, phenyl hydride, pyrobenzol.

Benzin, petroleum benzin, and benzine are chemicals that do not contain benzene.

Benzene exposure occurs when you:

–

Breath in (inhale) vapor or liquid particles (from actions such as spraying or splashing) containing benzene;

–

Have skin or eye contact with liquid or vapor containing benzene. Benzene is absorbed through the skin. Absorption occurs more rapidly with abraded skin or when benzene is present in solvents (as an ingredient or contaminant) which are readily absorbed;

–

Swallow (ingest) benzene.

Some benzene that enters your body will be absorbed into the bloodstream. Once in the bloodstream, benzene travels throughout your body and can be temporarily stored in the bone marrow and fat.

Benzene is converted to products, called metabolites, in the liver and bone marrow. Some of the harmful effects of benzene exposure are caused by these metabolites.

Most of the metabolites of benzene leave the body in the urine within 48 hours after exposure.

Medical monitoring is necessary to detect changes in your body's blood-forming system, including the bone marrow. These changes can occur due to repeated or prolonged, unprotected exposure to benzene, even at relatively low concentrations. Such changes can lead to various blood disorders, ranging from anemia to leukemia, an irreversible, fatal disease. Many of these disorders may occur without symptoms.

Benzene is classified as a confirmed human carcinogen (Group 1) by the International Agency for Research on Cancer (IARC).

To learn more about the medical monitoring process, see Medical evaluation, WAC 296-849-12030.

Unprotected exposure to benzene is associated with various health effects including symptoms and diseases associated with either short-term (acute) exposure or long-term exposure (chronic).

An initial stimulatory effect on the central nervous system (brain and spinal cord) can occur, characterized by exhilaration, nervous excitation (irritability), and/or giddiness. This may be followed by a period of depression, drowsiness, or fatigue.

Headache, dizziness, nausea, or a feeling of intoxication may develop.

A sensation of tightness in the chest may occur, accompanied by breathlessness. Ultimately the victim may lose consciousness.

In severe inhalation cases, tremors, convulsions, and death may follow due to respiratory paralysis or circulatory collapse in a few minutes to several hours.

Aspiration of small amounts of liquid benzene immediately causes pulmonary edema (excessive accumulation of fluid in lung tissues) and hemorrhage of pulmonary tissue.

Direct contact may cause redness (erythema).

Benzene has a defatting action on skin. Repeated or prolonged contact may result in any of the following:

–

Primary irritation;

–

Dry skin;

–

Scaling dermatitis (inflammation);

–

Development of secondary skin infections.

Localized effects from vapor or liquid contact on the eye are slight. High concentrations of benzene are irritating to eyes (causing a stinging sensation) and mucous membranes of the nose and respiratory tract.

The blood forming (hematopoietic) system is the main target for benzene's toxic effects. These effects can vary from anemia to leukemia, an irreversible, fatal disease. Many of the toxic effects may occur without symptoms.

Most importantly, prolonged exposure to small quantities of benzene vapor is damaging to the blood forming system. This damage has occurred at concentrations of benzene that may not cause irritation of mucous membranes or unpleasant sensory effects.

Early signs and symptoms are varied and often not readily noticed and nonspecific. These include:

–

Subjective complaints of headache, dizziness, and loss of appetite may precede or follow clinical signs;

–

Rapid pulse and low blood pressure, in addition to a physical appearance of anemia, may accompany a subjective complaint of shortness of breath and excessive tiredness.

–

Bleeding from the nose, gums, or mucous membranes;

 

–

Development of purpuric spots (small bruises).