OCCUPATIONAL HEALTHBENZENE

PADDINGTON T. MUNDAGOWA160097

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

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

SOURCES & USES OF BENZENE

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

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.

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

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.

CONCLUSIONHazardous 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

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

THANK YOU KEAOLEBOGA