Additional Information about Benzene



Exposure Limits as Set by the Washington State Department of Labor & Industries (at WAC 296-62-07523):


            8-hour Permissible Exposure Limit (PEL):                                    1.0 ppm

            15-minute Short Term Exposure Limit (STEL):                      5.0 ppm

            8-hour Action Level (AL):                                                                                           0.5 ppm




Benzene liquid is highly flammable.  It should be stored in tightly closed containers in a cool, well ventilated area.  Benzene vapor may form explosive mixtures in air.  All sources of ignition must be controlled.  Use non-sparking tools when opening or closing benzene containers.  Fire extinguishers, where provided, must be readily available.  Know where they are located and how to operate them.  Smoking is prohibited in areas where benzene is used or stored.


Benzene can affect your health if inhaled, if it contacts skin or eyes, or if ingested.  The most frequent work place route of entry is by inhalation, but benzene can be absorbed through the intact skin and will be absorbed faster through abraded skin.


High, short-term (acute) exposures may result in feelings of breathlessness, irritability, euphoria, giddiness, or irritation of the eyes, nose or respiratory tract.  Also, headache, dizziness and feelings of nausea or intoxication may occur.  Severe exposures may lead to convulsions and loss of consciousness.


Periodic exposures at lower levels (chronic exposures) may result in various blood disorders, ranging from anemia to leukemia (an irreversible, fatal disease).  Many blood disorders associated with benzene exposure may occur without symptoms.


Exposure Monitoring:


The supervisor must determine by breathing zone air monitoring if employees are over the AL or STEL.  If levels are below the AL and STEL, no further air sampling is required unless procedures change.  Affected employees must be informed of air monitoring results within 15 days of the supervisor receiving the results.


Labeling Requirement:


All containers of benzene must bear the following label warning:



Contains Benzene

Cancer Hazard



Training Requirements:


The Principal Investigator or supervisor must provide initial training to all personnel using benzene.  If airborne levels reach or exceed the AL, annual benzene training is required.  The training content must include the hazards of benzene, safety information, regulatory requirements, signs and symptoms of possible exposures to benzene, and medical surveillance requirements.


Medical Surveillance:


Any employee who is exposed to benzene above the AL for more than 30 days per year, or exposed to benzene above the PEL for more than 10 days per year, must be evaluated by the Occupational Health Nurse.  Based on the evaluation results, the nurse may recommend further evaluation, exposure restrictions, or job reassignment.


Please contact EH&S at 543-7388 for safety information, guidance for air monitoring strategies, equipment and analytical result interpretation.






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