Benzene is a natural component of crude oil and refined petroleum that is used widely as a solvent and in the manufacture of chemicals. It is highly toxic, carcinogenic, and exposure can cause blood disorders like leukemia. Sources of benzene exposure include tobacco smoke, vehicle exhaust, industrial emissions, and its use as a solvent. Symptoms of exposure include irritation and effects on blood and immune function. Workplace controls and personal protective equipment can help limit exposure. Occupational health specialists can work to reduce the use of benzene and educate about the risks of exposure.

1. OCCUPATIONAL HEALTH
BENZENE
PADDINGTON T. MUNDAGOWA
160097

2. PRESENTATION OUTLINE
• Introduction
• Sources & uses of benzene
• Health hazards of benzene
• Sources of exposure
• Symptoms of exposure
• Effects of exposure
• Workplace control & practise
• Conclusion
• Refences

3. INTRODUCTION
• The World Health Organisation WHO (2010) estimates
that 25% of the global burden of diseases is linked to
environmental factors including exposure to toxic
chemicals e.g. benzene
• Benzene was discovered by Michael Faraday in 1825
• It is an aromatic hydrocarbon compound
• Also referred to as phenol, benzol, phenyl hydride
• Chemical formula C6H6

4. SOURCES & USES OF BENZENE
SOURCE
• A natural component of crude oil & refined petroleum
• It is sometimes emitted from volcanoes
• present in tobacco smoke & forest fires
USE
• As a solvent in extraction of other substances
• In the manufacture of plastics, resins, nylon, synthetic
fibres, lubricants, dyes, detergents, drugs, pesticides

5. PROPERTIES OF BENZENE
•A very toxic chemical
•It is colourless
•Highly flammable
•Soluble in water & floats on water
•Very volatile when exposed to air
•Carcinogenic & mutagenic
•Lipophilic
•Has an aromatic odour

6. SOURCES OF EXPOSURE
OUTDOORS
•Burning coal & crude oil
•Ambient air around waste site
•Gas stations & motor vehicle exhaust fumes
•Industrial emissions
•Petrol vapour
•Tobacco smoke inhalation

7. SOURCES OF EXPOSURE
INDOORS
•Tobacco smoke
•Industrial use of benzene
•Air from benzene containing products ( glue,
paint, wax, detergents )

8. SYMPTOMS OF BENZENE
EXPOSURE
INHALATION SYMPTOMS:
• Irritated nose and throat, sneezing, coughing
• drowsiness, dizziness, confusion, tremors,
unconsciousness, headaches, euphoria
• rapid and irregular heart beat, vascular
congestion in brain
• congestive gastritis
• kidney congestion
• death

9. SYMPTOMS OF BENZENE
EXPOSURE
INGESTION SYMPTOMS:
•Vomiting, causing aspiration, breathing problems
and coughing,
•irritation of the stomach, toxic gastritis, pyloric
stenosis
•dizziness, sleepiness, convulsions,
• rapid and irregular heart beat
•death

10. EXPOSURE TO
BENZENE:EFFECTS
•Severity of effects is dependent on amount, route
and length of exposure time, age and pre existing
medical condition of the person exposed.
•Damage to both humoral and cellular
components of the immune system can occur in
humans following inhalation exposure
•Damage the immune system by altering antibody
blood levels

11. LONG TERM EXPOSURE TO
BENZENE
Exposure of a year or more can cause:
• harmful effects on the bone marrow resulting in aplastic
anaemia
• excessive bleeding
• Cancers e.g. blood cancer
• Weakening of the immune system, making one susceptible
to infection
• Irregular menstrual periods in women & decreased size of
ovaries
• Drying, red scaling of the skin (dermatitis)
• memory loss, difficulty in sleeping & distal neuropathy

12. PERMISSIBLE LIMITS FOR
BENZENE
• The Occupational Safety and Health Administration (OSHA)
limits work place exposure to benzene in the air to 1ppm
(part per million) during an 8 hr work day and a maximum
of 5ppm over any 15 minute period.
• Recommended airborne exposure limit (REL) is 0.1 ppm
averaged over a 10 hr working shift and 1 ppm not to be
exceeded during any 15 minute work period
• Threshold Limit Value (TLV) is 0.5 ppm averaged over an 8
hour work shift and 2.5 ppm as a short term exposure limit
(STEL)
• The permissible limit is set low to prevent leukaemia

13. WORK PLACE CONTROLS AND
PRACTICES
EMPLOYERS
•Label process containers clearly
•Provide employees with hazard information and
training
•Monitor airborne chemical concentrations
•Use of less hazardous substitutes e.g. toluene
•Use engineering controls if concentrations exceed
recommended exposure levels

14. WORK PLACE CONTROLS AND
PRACTICES (CONT.)
• Provide eye wash fountains and emergency showers
• Provide employees with personal protective clothing
• Prohibit smoking & eating in the work stations
• The employer should ensure that all workers exposed
to greater than 0.5 ppm of benzene should undergo a
medical test before their first exposure and every 12
months there after

15. WORK PLACE CONTROLS AND
PRACTICES (CONT.)
EMPLOYEES
• shower if skin comes in contact with benzene
• Always wash at the end of a work shift
• Change into clean clothing if clothing becomes contaminated
• Do not take contaminated clothes home
• Do not smoke, eat or drink in areas where chemicals are being
handled, processed and stored.
• Wash hands carefully before eating, smoking, drinking, applying
cosmetics and using the toilet.
• Always use protective clothing provided

17. WORK PLACE CONTROLS AND
PRACTICES
FIRE HAZARDS
• In case of fire, only trained personnel should fight the fire
• Use dry chemical or water as a fog
• Be aware of exploding containers and poisonous gases
SPILLS AND EMERGENCIES
• Should be done by trained and equipped personnel
• Evacuate other personnel and eliminate all ignition sources
• Absorb liquid in dry vermiculite, sand, earth or similar material
and deposit in sealed containers
• Ventilate area of spill or lick

18. WORK PLACE CONTROLS AND
PRACTICES (CONT.)
HANDLING AND STORAGE
•Proper training needed
•Regulate, mark area where benzene is handled,
used and stored
•Take heed because benzene reacts violently or
explosively with oxidizing agents like chlorates
and strong acids e.g. hydrochlorine.
•It is not compatible with liquid oxygen and
hydrogen.

19. WORK PLACE CONTROLS AND
PRACTICES (CONT.)
•Store in tightly closed containers in a cool, well
ventilated area away from heat.
•Metal containers involving the transfer of benzene
should be grounded and bonded
•Use explosive proof electrical equipment and
fittings whenever benzene is used, handled,
manufactured and stored.
•Use only non-sparking tools and equipment
especially when closing and opening containers of
Benzene.

20. TREATMENT OF EXPOSURE
•Treatment is done with supportive care in a
hospital setting
•No specific antidote exists for benzene poisoning
•The most important advice is seek medical
treatments as soon as possible

21. OCCUPATIONAL HEALTH
SPECIALIST’S ROLE
• Participate in the development & implementation of
policies and legislations to remove benzene from
consumer products
• Raise public awareness regarding sources of exposure to
benzene and risk mitigation measures
• Conduct educational activities to discourage the use of
benzene for cleaning and degreasing in industry
domestically and discourage domestic use of benzene
containing products.

22. CONCLUSION
Hazardous chemical exposure remains a public
health risk and the consequences are immensely
felt in developing world. Thus, it is imperative for
public health practitioners to engage themselves in
the assessment of health and environmental risks
associated with the use of toxic chemicals such as
benzene so as to prevent associated hazards

23. REFERENCES
• Center For Disease Control and Prevention (CDC), (2006), Pocket guide to
chemical hazards, National Institute For Occupational Safety And Health
(lNIOSH)
• Division Of Occupational & Safety Health, (2009), Benzene: Training on
hazards of benzene in the workplace, Washington State Department of
Labour & Industries
• World Health Organization (WHO) ,(2010), Public Health and The
Environment, Geneva, Switzerland
• World Health Organization (WHO), (2010), Risk Assessment Tool kit.
Chemical Hazards 2010, IPCS Harmonization Project
• www.osha.gov/SLTC/benzene/ American Cancer Society

24. THANK YOU
KEAOLEBOGA