Igc2 Element 7 Chemical Biological 4sl55

IGC 2 : ELEMENT 7 CHEMICAL & BIOLOGICAL HEALTH HAZARDS & CONTROL

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FORMS OF CHEMICAL AGENTS • DUSTS

•VAPORS

• FUMES

•LIQUIDS

• GASES

fibers

• MISTS

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FORMS OF BIOLOGICAL AGENTS • BACTERIA • VIRUS • FUNGI • PARASITES

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The four main classifications of occupational health hazards are: 1. Physical: Machinery, Electricity, Heat, Noise 2. Chemical: Acids, Alkalis, Asbestos 3. Biological: HIV Virus, Legionella, Bacteria 4. Ergonomic: Posture problems, Fatigue

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1. PHYSICAL HAZARDS Examples include: • Heat Heat cataract, heat stroke • Lighting Eye problems • Noise Noise induced hearing (occupational deafness) • Vibration Vibration induced white finger • Radiation Radiation sickness (at ionising wavelengths), burns, arc eye • Dust Silicosis, coal workers • Pressure Decompression sickness • Asbestos fibres Asbestosis, lung cancer, mesothelioma

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2. CHEMICAL HAZARDS Examples include: • • • • • •

Acids and alkalis Metals Non metals Gases arsine poisoning Organic bladder cancer compounds

Dermatitis Lead and mercury poisoning Arsenic and phosphorus poisoning Carbon monoxide poisoning; Occupational cancers, e.g.

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3. BIOLOGICAL HAZARDS Examples include: • Animal borne Anthrax, brucellosis, leptospirosis, rabies • Human borne Viral hepatitis • Vegetable borneAspergillosis (Farmer’s Lung) • Others (water/land) Legionella

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Control measures to control biological hazards should be: •Cleaning / disinfection •Water treatment programmes •Vermin control •Procedures for handling, containment and disposal •Personal hygiene i.e. cover wounds •Immunisation •Health surveillance •Specific training •Personal Protective Equipment

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Dusts • • •

Solid particles suspended in the air for a period of time. Size ranges from 0.1µm (fine) to 100µm (coarse). Produced by mechanical process e.g. grinding, or by construction process e.g. demolition, or other specific tasks e.g. cotton or wood work

Respirable dust: fine dusts that penetrate deep into the lungs & stay there (in rare cases enters the blood stream) e.g. Cement & Silica

Inhalable dust: capable of entering nose & mouth during breathing, without reaching lower levels of respiratory system.

Fumes •

Formed when a material from a volatilized solid condenses in cool air. Usually extremely fine <1.0µm e.g. welding & soldering fumes.

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Gases •

Formless fluids which expand to occupy the space in which they're confined e.g. Carbon Monoxide, Hydrogen Sulphide… etc

Mists •

Suspended liquid droplets generated by condensation of liquids from the vapor back to the liquid state or by breaking up liquid into dispersed state e.g. paint spraying mist (atomization).

Vapors •

Volatile forms of substance that are normally in the solid or liquid state at room temperature & pressure e.g. solvents used in degreasing (toluene, acetone… etc).

Liquids •

Fluids that exist normally at temperature between boiling & freezing.

Smoke •

Aerosol of solid or liquid particles, <0.1µm in size, resulting from incomplete combustion of carbonaceous materials e.g. Carbon particles.

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Forms of Biological agent Fungi • • • • • •

Very small organisms, sometimes single cell or multi cellular e.g. yeast Reproduce by spore formation Can not produce their own food, they feed on dead organic matter or living hosts Spores can cause allergic reaction when inhaled Cause mild infection in man e.g. athlete's foot or severe e.g. ring worm Many fungal infections can be treated by anti fungal or anti biotic medication

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Forms of Biological agent Bacteria • • •

Very small single cell organisms, much smaller than human body cells e.g. Tuberculosis. They can survive outside the human body. Can be destroyed by antibiotics, but now they're getting resistant.

Viruses • • • •

Minute non-cellular organisms which can only reproduce & survive within a host cell. Very much smaller than bacteria & not controlled by antibiotics. Continually developing new strains with new genetic material e.g. Influenza, hepatitis & AIDS Usually only defeated by human body defense & healing mechanisms.

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CLASSIFICATION OF SUBSTANCES HAZARDOUS TO HEALTH

TOXIC CORROSIVE

OR CARCINOGENIC

OR HARMFUL

DISCUSS ACUTE & CHRONIC HEALTH EFFECTS 13

Harmful: Substance which if swallowed, inhaled or penetrates the skin, causes limited health risks. Risks can be minimized or removed by following the instruction provided with the substance.

Irritant: Non-corrosive substance which can cause skin or lung inflammation after repeated . People who react that way to a particular substance are sensitized or allergic to that substance.

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Corrosive: Substances that will cause chemical burns to human tissue. Usually strong acid or alkali e.g. Sulphuric acid.

Toxic: Poisonous substance which will prevent the function of one or more organs within the body e.g. liver, kidney… etc.

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Carcinogenic: Substances suspected to promote abnormal development of cancer cells e.g. Asbestos.

Mutagenic: Substance that damage genetic material causing abnormal changes that can be ed on from one generation to another.

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HEALTH HAZARDS OF SPECIFIC AGENTS Ammonia: • • •

Colorless gas with distinctive odor, strongly alkaline. It is corrosive; burns skin, seriously damage the eyes, soreness & ulceration of throat, severe bronchitis & lung edema. Used in production of fertilizers & synthetic fibers.

Chlorine: • • •

Toxic, greenish gas with a pungent smell. Highly irritant to the respiratory system; severe bronchitis & lungs edema Used as a disinfectant for drinking water & swimming pool water.

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HEALTH HAZARDS OF SPECIFIC AGENTS Carbon Dioxide:

Organic Solvents:

•

Colorless, odorless gas & heavier than air.

•

•

It represses the respiratory system causing death by asphyxiation.

Used widely in the industry as cleansing & degreasing agents.

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•

At low concentration; headache, sweating & loss of consciousness.

Used as varnishes, paints, adhesives, glue strippers, thinners & printing inks.

•

•

Produced as by product in fermentation processes e.g. brewing

All are heavier than air, sensitizers & irritants to eyes & respiratory system

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Some are narcotics, cause dermatitis, affect the brain & nervous system. 18

HEALTH HAZARDS OF SPECIFIC AGENTS Carbon Monoxide: •

Colorless, odorless & tasteless gas, impossible to detect without detection device.

•

It enters the blood & binds with the red blood cells more readily than Oxygen & restricts Oxygen supply to vital organs.

Silica: •

Harm is caused by inhalation of silica dust which can lead to silicosis, fibrosis & pneumoconiosis.

•

Respirable dust is the most harmful as it is trapped in the alveoli.

•

It headaches, nausea, drowsiness, flushed appearance & ultimately asphyxiation.

•

With silicosis; breathing becomes more difficult & later on lung & heart failure might occur.

•

Produced as an exhaust gas from • a vehicle or a heating system as a result of incomplete combustion.

Mining, Quarries, Stone working, ceramic, pottery & brick making

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Isocyanates: • • • • •

Volatile organic compounds. Irritants & sensitizers. They cause inflammation of the nasal age, throat & bronchitis. Health hazards to fire fighters. Widely used for products such as printing inks, adhesives, & the manufacture of plastic.

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HEALTH HAZARDS OF SPECIFIC AGENTS Asbestos: Blue, Brown & White

Lead: • • •

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Heavy, soft & easily worked metal. Affects mainly the brain & spinal cord, the blood & blood production. Effects are usually chronic & cumulative, normally enters body by inhalation, ingestion or skin . Early symptoms include colic, headache & nausea

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Produces fine fibrous dust of respirable size that can become lodged in the lungs.

•

Fibers can be very sharp causing damage to the lining of the lungs over a very long period of time.

•

Can lead to asbestosis (fibrosis), lung cancer or Mesothelioma (cancer of the lung lining).

•

Typical sites include ceiling tiles, asbestos cement roof & wall sheets.

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HEALTH HAZARDS OF SPECIFIC AGENTS Leptospirosis: Weil's disease •Caused by bacteria found in the urine of rats. •Manifests by fever & flu like symptoms. •At late stage kidneys & liver are affected & Jaundice appears. •Treated by antibiotics. No vaccine for humans. •Common in sewage workers (through skin or by ingestion), dogs & pigs' handlers.

Legionella: •

Airborne bacteria found in a variety of water sources.

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Produces a form of atypical pneumonia & influenza like symptoms caused by the bacteria penetrating the alveoli of the lungs.

•

The bacteria require food in the form of algae or other bacteria (in stagnant water).

•

Common in water system e.g. cooling towers, showers & airconditions if not properly maintained & treated.

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HEALTH HAZARDS OF SPECIFIC AGENTS Hepatitis: •

Disease of the liver cause by a virus (A, B, C & others) or some hazardous substances e.g. organic solvents.

•

Causes high temperature, nausea & jaundice.

•

The Virus can be transmitted by infected faeces (A), infected blood (B & C) or sexually (C).

•

Usually destroys the normal architect of the liver cells in an irreversible manner  liver failure.

• Health care workers, care givers & any workers involved with bodily fluids are at high risk of infection by ingestion or by direct entry (needle stick). • Key controls include: personal hygiene, PPE, water treatment, vaccination, & proper disposal of any contaminated waste. 23

Route of Entry Defense Mechanism Inhalation • • • • • • •

Breathing in the substance with the normal breathing air. Main & most dangerous route of contaminants to the body. Contaminants then enter the lungs where they have access to the blood stream & body systems. Hairs & mucous in the nose that traps the dust. Sneezing & coughing reflexes; get rid of inhaled particles. Tiny hairs (cilia) hitting upwards; carry inhaled particles back to larynx to be spat or swallowed. White blood cells in the tiny blood vessels around the alveoli that attack foreign bodies by different mechanisms.

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Ingestion • • • • • •

Contaminants enter through the mouth & are swallowed into the stomach & digestive system. Not a significant route of entry. Occurs accidentally, due to poor hygiene or to commit suicide. Stomach has acids & various enzymes that kill biological contaminants e.g. bacteria Some contaminants will cause an immediate reaction initiating other defense mechanisms e.g. vomiting & diarrhea Many toxics can be broken down in the liver.

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Skin Absorption •

Substances come into with skin & enter either through pores or wounds. • Solvents & bacteria e.g. tetanus can enter in this way Note: Injection is another route of entry, through contaminated needles, sharp objects or gases/liquids under pressure. • Skin secretes natural protective oils to protect against waters & weak chemicals. • It has sensory nerves to alert against high temperature & initiate defense reflexes e.g. withdrawal reflex • Skin has special pigments to protect against UV of the sunlight. • Dermatitis; reaction showing body's fight against harmful substances.

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GROUP ACTIVITY DISCUSS THE ENTRY ROUTES OF HAZARDOUS SUBSTANCES TO THE HUMAN BODY & THE DEFENSE MECHANISMS

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OCCUPATIONAL EXPOSURE LIMITS • WORKPLACE EXPOSURE LIMITS WEL IS: "The maximum concentration of airborne hazardous substances that people inhale over a specified period of time – known as: Time Weighted Average". – In USA the WEL is known as Threshold Limit Values TLV – In Europe EU WEL is known as Indicative Limit Values ILV • Long-term Exposure Limit (LTEL) or 8 hour reference period of exposure (considers chronic effects). • Short-term Exposure Limit (STEL) or 15 minute reference period of exposure (considers acute effects).

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– In USA the WEL is known as Threshold Limit Values TLV – In Europe EU WEL is known as Indicative Limit Values ILV

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Limitations of OEL: • Specifically quoted for 8 hour period. • Used only for workplace exposure & not for non occupational exposure. • They should not be used in cases of emergency build up of hazardous substances e.g. in confined space emergencies • Chemicals can enter the body by other routes other than inhalation!!

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SOURCES OF INFORMATION • LABELS • INVENTORY • MATERIAL SAFETY DATA SHEET

MATERIAL SAFETY DATA SHEET

• TRADE ASSOCIATION PUBLICATIONS • THE INTERNET

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1] Product labels: • • • •

Chemical name Details of the hazards & classification Precautions needed Name & s of the manufacturer

2] Inventory: • •

Complete inventory of all hazardous substances in the workplace Search well & look for expired & old stored forgotten chemicals

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3] Material Safety Data Sheet MSDS: • • • • • • • • • •

Manufacturer's name & details Chemical composition of the hazardous substance Chemical & physical properties of the substance First Aid & Fire Fighting measures Spill mitigation measures Adverse Health effects & OEL Handling, transport & storage Disposal consideration Environmental impact Other information

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4] Trade association publications, Industrial codes of practice & specialist reference manuals. 5] EU list of ILV / ACGIH (American Conference of Governmental Industrial Hygienists) list of TLV / HSE list of OEL / UK COSHH Guidelines 6] Search the Internet (see element 1 for useful websites).

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BASIC SURVEY TECHNIQUES FOR HEALTH RISKS

Stain Tube Detector: Grab sampler •

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Direct reading glass indicator tubes filled with chemical crystals change color when a particular hazardous substance es through them. The glass tube is opened at each end & fitted into a pumping device.

ive Sampling: • •

Measured over a full working period of time Done through a badge worn by the worker containing absorbent

Smoke Tubes: •

Generate a white smoke which may be used to indicate the direction of air flow

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BASIC SURVEY TECHNIQUES FOR HEALTH RISKS Direct Reading Instruments: • • • • •

Sophisticated analyzers Can only be used by trained & experienced operatives. Infra red gas analyzers are the most common Very accurate & give continuous or TWA Very expensive

Dust Observation Lamp: • •

Enables dust particles which are normally invisible to human eye to be observed in the light beam This dust is usually respirable

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TOXICOLOGY Definition: •

The study of how different materials will affect the human body.

•

The effect that a substance will have on the body will depend on a number of factors:

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The effect that a substance will have on the body will depend on a number of factors: – Route of Entry – Toxicity – Dose & Response

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The routes of entry are: • Inhalation • Ingestion • Absorption • Injection

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– Toxicity

• The potential of a substance to cause harm to living things.

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– Dose & Response Dose is defined as: • How much of a substance you are exposed to and how long the exposure to the substance lasts. • This produces the response which is how the body reacts to the exposure. The response can depend on things such as: body weight, age, skin type, sex, diet and general health.

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Sensitising dermatitis (eczema) •A second form of dermatitis is called sensitising dermatitis. In this case a person exposed to the substance develops dermatitis, when taken away the dermatitis repairs but the body gets ready for later exposures by preparing the body’s defence mechanisms. A subsequent small exposure is enough to cause a major response.

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TARGET ORGANS A Target Organ is defined as: • An organ within the human body on which a specific toxic material exerts it effects e.g. lungs, liver, brain, skin, bladder and eyes. Substances can also target the body’s systems e.g. central nervous system, circulatory system, reproductive system.

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Examples of substances which have a systemic effect and their target organs are: •Alcohol - central nervous system, liver •Lead - bone marrow and brain damage •Mercury - brain, central nervous system

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If High Risk occupational exposure limits are exceeded the employer should: •Stop the process •Remove employees from area •Investigate reason •Assess existing controls •Monitor procedures •Assess ill health to workers •Record incident

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1) IDENTIFY THE HAZARDS • • • • • • • • • •

How much of the substance is in use or produced by the process What is the activity at risk How long and how often is the exposure Who can be exposed and how How can the substance enter the body In what form is of the substance What is the concentration of the substance Is the substance assigned an exposure limit Are there any ill-health reports Look at the results of health surveillance

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2) DECIDE WHO MIGHT BE HARMED AND HOW • The employees who work in the area can obviously be affected but consideration also needs to given to other employees, contractors, visitors and of the public. Consideration also needs to be given to particularly vulnerable people, e.g. pregnant workers, the disabled and those with health problems. •

Operators, Others, Pregnant and young worker

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3) Evaluate the Health risk & existing precautions • Likelihood and Severity • Existing control measures • Judgement about need for further control measures The existing control measures should be identified to decide if they are used and adequately control exposures to the substance. If not a decision must be made on further control measures.

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4) Record the significant findings The significant findings should be recorded. The assessment may also record such things as: • Number of affected people • Adequacy of existing controls • Further precautions, if necessary

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5) REVIEW THE ASSESSMENT • Management of health and safety is an ongoing process and management must regularly review all the hazardous substances assessments carried out to ensure that they are still valid. The time between reviews will depend on the type of risk, the work and the employer’s judgment on the likelihood of changes occurring.

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The assessment must be immediately reviewed when there is evidence it is no longer valid e.g.: •The results of examination and tests of engineering controls indicate problems •The results of monitoring indicate too high exposure levels •The results of health surveillance indicate health problems •Complaints are received from supervisors, employees etc. about defects in the control systems

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Assessment should also be reviewed if conditions change or new information comes to light e.g.: •New process or substance is introduced •Exposure limit is changed •Someone contracts a disease •Complaints of ill health from workforce •New guidance is published on control measures •Increase in use of hazardous substance •Supervision reports improper use of equipment •Enforcement actions •Compensation claims

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Emergency Procedures • • • • • • • • • •

The emergency procedure should include: First aid facilities Relevant safety drills Suitable warning devices Suitable training of staff PPE Emergency showers and eye-wash facilities Spillage and leakage procedures Evacuation procedures Warnings to other people

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To be effective the emergency plan must: • • • • • •

Identify all potential accident or emergency situations Introduce controls to prevent accident and emergency situations arising Include procedures to minimise the consequences of any potential environmental impacts Have clearly documented plans and procedures for responding to emergencies Be periodically reviewed and revised if necessary Be periodically tested if possible

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Waste Management • Waste can be described as the materials or substances that are no longer needed which are discarded or thrown away. Waste generation is a major environmental problem with more being generated annually.

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Storing Waste When storing hazardous materials the precautions should be: •Storage area of a sufficient size •Storage area suitably located away from drains etc. •Storage area clearly labeled •Individual containers clearly labeled •Different types of waste stored separately •Incompatible wastes never stored together •Appropriate containers for type of waste •Storage of waste kept to a minimum •Protect wastes from the elements if necessary •If necessary protect storage area with bunds etc. •Do not dispose of hazardous waste in general waste skips •Ensure storage area is secure

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CONTROL MEASURES • Eliminate or stop using the hazardous substance

• Reduction of the time of exposure; job rotation & shifts

• Substitute hazardous substance by a less hazardous one

• Good hygiene & housekeeping

• Total or partial enclosure of the process; use glove box • Local Exhaust Ventilation • Dilute or general Ventilation

• Training, information, work instructions & supervision • Health surveillance & Personal Hygiene • Personal Protective Equipment

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LOCAL EXHAUST VENTILATION

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LOCAL EXHAUST VENTILATION – Collection hood & intake: The nearest part to the work piece, the speed of the air entering the intake is important; if it is too low then the fumes may not be removed. – Ventilation ducting: Normally acts as a conduit for the contaminated air & transports it to a filter & settling section. It is very important to inspect & clean this section regularly. – Filter or other air cleaning device: located between the hood & the fan, filter removes the contaminant from the air stream. Requires regular attention & proper cleaning. – Fan: moves the air through the system. Should be positioned so that it can be easily maintained & needs to be of right type & size. – Exhaust duct: exhausts the air to the outside of the building. Should be checked regularly to make sure there is no leakage or corrosion due to weather.

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DILUTION (GENERAL) VENTILATION ADVANTAGES: • Uses either natural ventilation; doors & windows •

•

Or fan assisted forced ventilation to ventilate the whole working room; by inducing a flow of clean air, extraction fans fitted into the roof. Operates by removing the contaminant or reducing the concentration to an acceptable level.

Limitations: • Certain area of the working room will not receive the ventilated air & a build-up of hazardous substance will occur •

The flow patterns are affected by doors, windows & furniture.

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Not suitable for dust extraction

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PERSONAL PROTECTIVE EQUIPMENT Respiratory Protective Equipment: •Filtering half mask; disposable respirator, removes respirable size dust particles. Covers nose & mouth & provides protection against some vapors & gases. •Half mask respirator; made of rubber or plastic & covers the nose & mouth. Air is drawn through a replaceable filter cartridge. Used for vapor, gases or dusts. •Full face mask respirator; similar to half mask but covers the eyes. •Self contained breathing apparatus; air is supplied from a compressed air cylinder

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• Powered respirator; battery-operated fan delivers air through a filter to the mask. • Fresh air hose apparatus; fresh air is delivered through a hose to a sealed face mask from an uncontaminated source. Air is delivered by wearer, by natural breathing or mechanically by fan. • Compressed air line apparatus; air is delivered through a hose from a compressed air line. Can be continuous flow or on demand.

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PERSONAL PROTECTIVE EQUIPMENT HEAD PROTECTION HAND PROTECTION FEET PROTECTION

EYE PROTECTION

LAST RESORT 63

2] Hand & Skin Protection • •

Use of glove; against chemicals, sharp objects, heat, cold & rough working. Use of barrier creams; pre-work & after-work to replace natural skin oils.

3] Feet protection • • •

Wide range of safety boots available Against chemicals, heavy objects, sharp objects Anti slippery soles & against electricity

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4] Head protection • •

Hard hats; construction, anti electric shock… etc Bump caps

5] Eye protection • • •

Safety glasses (spectacles); low risk hazards Safety goggles; splashes, dust & solvent vapors Face visors; against steaming up in hot & humid environment

6] Torso protection •

Coveralls & Aprons; against spills, sunlight & to protect against loose clothes getting entangled in moving machinery parts.

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Air Pollution: • Outdoors; machinery & industry emissions & smoking. Indoors; heating systems & sprays… etc • Mainly by emissions; carbon monoxide, sulphur dioxide, nitrogen dioxide & lead… etc • Leads to Acid rain & global warming • Have serious Health effects on human beings

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Water Pollution: • Pollution of rivers & other water sources can have serious effects on the health of living organisms. • Leakage from industrial soak away or chemical factories. • Sewer discharge & oil spill contaminating underground water • Water samples should be taken from water sources & sewers. • MSDS to advise on proper disposal of different hazardous substances

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Waste Management Hierarchy: • • • • •

Prevention: by changing the process so that the waste is not produced. Reduction: improving the efficiency of the process Reuse: by recycling the waste back into the process Recovery: releasing energy through the combustion or recycling of waste. Responsible disposal: disposal in accordance with regulatory requirements & never mix different types of hazardous wastes.

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