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WEEK 2 – ELEMENT 6
Chemical & Biological Health Hazards and Control
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Classification of Occupational Health Hazards Physical: Machinery, Electricity, Heat, Noise Chemical: Acids, Alkalis, Asbestos Biological: HIV Virus, Legionella, Bacteria Ergonomic: Posture problems, Fatigue Psychological: Stress, Shock, Anxiety
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Classification of Health Hazards Health Hazard
Workplace health hazard
Health effect of exposure
Physical
Noise
Noise induced hearing loss
Chemical
Asbestos
Asbestosis
Biological
Rats urine
Leptospirosis / Weil’s Diseasse
Ergonomic Repetative tasks
Work related upper limb disorders
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Biological Hazards Biological hazards can be bacteria or viruses Diseases caused by biological agents include: • Legionnaires disease a type of pneumonia or lung infection
• Hepatitis blood borne viral infections • Weils disease fatal infection transmitted urine from infected rats •
Anthrax disease caused by the bacteria found in animal hides
• Rabies Rabies is a virus transmitted bite from a wild infected animal
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Biological Hazards Control Measures 1) 2) 3) 4)
Cleaning / Disinfecting Water treatment programmes Vermin control A pest animal prohibited, controlled Procedures for handling, containment & disposal 5) Personal hygiene 6) Immunisation to build resistance to specific infections 7) Health surveillance strategies and methods to detect and assess systematically the adverse effects of work on the health of workers.
8) Specific training 9) PPE
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PHYSICAL FORMS OF HAZARDOUS SUBSTANCES • • • • • • • •
Gases (Co2) Vapour (toluene) Mists and aerosols Smoke (coal burning) Fumes (welding) Dusts (floor mill dust) Liquids (chemicals) Solids (Lead ingot)
(deodorant)
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Hazardous Substances Symbols (1) Irritant: Inflammation on contact with skin, eyes or mucous membrane may cause inflammation e.g. adhesives and detergents
Corrosive: Destruction of living tissue at point of contact (skin) strong acids or alkalis i.e. H2 SO4, Caustic, ammonia
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Hazardous Substances Symbols (2)
Harmful:
Substances which if swallowed, inhaled or penetrate the skin may cause damage to health e.g. Trichloroethylene
Very Toxic: Poisonous substances which in very low quantities may cause death, acute chronic damage to health e.g. cyanide
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Hazardous Substances Symbols (3)
Toxic: Poisonous substances which in low quantities may cause death, acute chronic damage to health e.g. Lead, Mercury, Arsenic
Carcinogenic: Substances which cause disorders in cell growth that may lead to cancer or increase its incidence e.g. Benzene
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Hazardous Substances Symbols (4)
Mutagenic: Substances which induce hereditable genetic defects or increase their incidence
Teratogenic: Toxic for reproduction. Substances which produce or increase the incidence of non heritable effects in progeny.
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TOXICOLOGY Definition: The study of how different materials will affect the human body
The factors to be considered are: 1) Route of Entry 2) Toxicity 3) Dose & Response
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TOXICOLOGY - Routes of Entry a) Inhalation
b) Ingestion c) Absorption d) Injection (Direct Entry)
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TOXICOLOGY - Routes of Entry Inhalation • most important route of entry • substances can directly attack lung tissue • responsible for 90% of all cases of industrial poisoning Ingestion • via the mouth • often accidental • poor hygiene
Absorption • through the skin • solvents may penetrate unbroken skin
•Injection • when skin is damaged • puncture of the skin • contact with liquid or gas under pressure
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Toxicity, Dose & Response Toxicity: The potential of a substance to cause harm to living things
Dose: How much of a substance you are exposed to and how long the exposure lasts Response: How the body reacts to the exposure
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Factors Affecting Response Body Weight Age
Skin Type Sex
Diet Health
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Ill-health Definitions Acute :
Is an immediate or rapidly produced adverse effect, following a single or short-term exposure to a hazardous substance, usually with a rapid or immediate response which is normally reversible. Chronic: Adverse health effect resulting from prolonged, repeated exposure to a hazardous substance the response being gradual (often unrecognised for a long time) may get worse with no further exposure and is often irreversible.
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Toxic Effects Acute: Headaches Dizziness Nausea Inflammation Eye irritation Unconsciousness Death
Chronic: Cancers Death Local Systemic Sensitisation
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Dermatitis Removal of natural oils from skin which causes reddening, soreness, cracking and bleeding of exposed skin. Usually occurs to arms and hands Causative Agents: Solvents, Detergents, Mineral oils, Diesel fuel, Cement, Dusts, etc.
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Measures to Prevent Dermatitis • • • • • • • •
Substitute/change process Clean working conditions & Properly planned safe systems Careful attention to skin problems Prompt attention to cuts etc. Use of PPE Barrier creams Pre-employment screening Information, instruction and training
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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 its effects.
Lungs
Brain
Asbestos, Coal dust
Lead, Mercury
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Target Organs Brain – lead Nasal passages – organic solvents Lungs – asbestos, chlorine, carbon dioxide, ammonia, isocyanates, silica, organic solvents, legionella
Eyes – ammonia
Kidneys – leptospirosis
Liver – hepatitis Blood – carbon monoxide Skin - detergents, isocyanates, mineral oils, acids, alkalis, organic solvents
Nerves – organic solvents, lead
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Occupational Exposure Limits (OEL) The maximum concentration of an airborne substance averaged over a reference period to which an employee may be exposed by inhalation • Threshold Limit Values (TLV) USA • Indicative Limit Values (ILV) Europe • Workplace Exposure Limits (WEL) UK High risk substances Other hazardous substances
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Action If OEL Exceeded 1) 2) 3) 4) 5) 6) 7) 8)
Stop the process Remove employees from area Make area safe Investigate cause Assess existing controls Monitor procedures Check workers health Record incident
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Asbestos Types
Diseases
White (Chrysotile)
Asbestosis
Brown (Amosite)
Mesothelioma
Blue (Crocidolite)
Lung cancer
Blue and brown asbestos are more hazardous than white
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Asbestos Uses Protective Clothing Insulation boards Pipework Lagging Cement Boards
Gaskets, Filters
Blue asbestos cloth on a boiler flue
Brake Linings Plasterwork
Sprayed for Insulation Workers at risk:
Asbestos insulating board in a wall partition
Maintenance, & Demolition workers
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Other Agents (1) Ammonia: A colourless gas with a pungent odour • Irritation to the eyes and upper respiratory tract • Used in printing and fertilisers Chlorine: A greenish gas with a pungent odour • Irritant to respiratory tract, abdominal pain, nausea (sensation of unease and discomfort in the stomach) • Used as a disinfectant in drinking water and swimming pool water
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Other Agents (2) Carbon Dioxide: A colourless, odourless gas Increases the rate of respiration, unconsciousness
Produced in fermentation, Fire protection Carbon Monoxide: A colourless, odourless and tasteless gas
Headaches, drowsiness, asphyxiation Incomplete combustion in boiler, vehicle exhausts
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Other Agents (3) Isocyanates: Volatile organic compounds
Irritation of skin and mucous membrane, asthma
Spray painting vehicles, manufacture of footwear
Lead: A heavy, soft and easily worked metal
Nausea, headaches, nervous system, death
Batteries, Plumbing and roofing work
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Other Agents (4) Silica: Found in sand, sandstone, granite
Silicosis
Building industry
Organic solvents: Dissolve other substances
Irritant to the eyes, skin, throat and lungs, headaches, nausea, dizziness
Used as a base in paint manufacturing, PVC, etc
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Other Agents (5) Leptospirosis or Weil’s: Caused by bacteria from rats’ urine
• Attacks kidneys and liver • Found in rivers, sewers, ditches, canals Legionella: An airborne bacterium found in water sources e.g. cooling towers, stagnant water • Breathing difficulties, pneumonia Hepatitis: Hazardous substances, viruses • Diseases of the liver, high temperature, jaundice • Health workers and workers handling bodily fluids
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AIRBORNE DUST Respirable dust: Airborne dust of such a size about 0.5 microns that it is able to enter the lungs during normal breathing
Respiratory diseases: • Asbestosis
(chronic inflammatory medical condition affecting the tissue of the lungs)
• Silicosis (occupational lung disease caused by inhalation of • • • •
crystalline silica dust)
Asthma chronic …the airways occasionally constrict Bronchitis (an acute inflammation of the air passages within the lungs) Lung Cancer Farmer’s lung (a disease of dairy farmers who handle contaminated hay)
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Body Defences against dust The nasal hairs Coughing and sneezing Eyes watering The ciliary escalator
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Indicators of Dust Problems Visible signs Complaints by employees Monitoring Health problems Equipment problems Blocked filters
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Assessing levels of dust Visual examination
Sampling for dust Personal samplers Fixed samplers Filters attached to pumps Sample for a fixed time
Dust lamps Direct reading instruments Dust accumulation
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Control Measures to Reduce Exposure to Dust
Eliminate at source Substitute with pellets Change process Use liquid process Enclose the complete process Ventilation Control by suppression Housekeeping Maintenance
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BODY’S DEFENCES The body’s defences to hazardous substances are: • Respiratory (Inhalation)
• Gastrointestinal (Ingestion) • Skin (Absorption) • Cellular mechanism (Injection)
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Respiratory (Inhalation) Defences • NOSE : Wetness & nasal hair • RESPIRATORY TRACT : Natural reflexes activate sneezing and coughing • CILIARY ESCALATOR – A barrier against infection. Pushes mucus and foreign bodies out through throat
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Body’s Defences (2) Gastrointestinal (Ingestion) Defences • • • •
Taste and smell Saliva Acid, enzymes and bacteria Vomit and diarrhoea
Skin Defences • • • •
Sebum Sensory nerves Melanin Blisters, rashes, inflammation
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Body’s Defences (3) Cellular Mechanisms (Injection) •
Scavenging Action
•
Secretion of defensive substances
•
Prevention of excessive blood loss
•
Repair of damaged tissues
•
The Lymphatic system
Other Defences •
Tears and blinking of the eyes
•
Pain
•
Hormones e.g. adrenalin
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Manufacturers Safety Data Sheet (1)
Identification of substance/preparation The manufacturer/supplier Composition/information on ingredients Hazard identification Health effects First Aid measures Fire fighting measures Accidental release measures Handling and storage Exposure controls
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Manufacturers Safety Data Sheet (2) Personal Protective Equipment Environmental/Disposal considerations Physical and chemical properties; Stability and reactivity; Toxicological information; Ecological information; Disposal considerations; Transport information; Regulatory information; Other relevant information.
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Product labels
Substance
Preparation
© TWI Gulf WLL 2008
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Risk and Safety Phrases Risk
Safety
R3 Extreme risk of explosion by shock, friction, fire R20 Harmful by inhalation R30 Can become highly flammable in use R45 May cause cancer
S2 Keep out of the reach of children S20 When using do not eat or drink S25 Avoid contact with eyes S41 In case of fire and or explosion do not breathe fumes
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Hazardous Substance Assessment 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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Hazardous substance Assessment 2) Decide who might be harmed and how
Operators, Others, Pregnant and young worker
3) Evaluate the Health risk & existing precautions
Likelihood and Severity
Existing control measures
Judgement about need for further control measures
4) Record the significant findings
Number of affected people
Adequacy of existing controls
Further precautions, if necessary
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Hazardous substance Assessment 5) Review the Assessment
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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Prevention and Control of Exposure 1) Eliminate the hazard 2) Reduce the risk by substitution 3) Isolate the people from the hazard Total enclosure, Segregate the people
4) Control Maintenance of controls, Change the work pattern, Hygiene, Housekeeping 5) Personal protective equipment 6) Discipline 7) Also information, Instruction, Training Remember - ERIC PD
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Emergency Procedures 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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Spillage Procedures
Isolation of the area
Evacuation of employees
Suitable PPE
Bunds to contain spillage/absorbent material
Contact with emergency services
Safe disposal of spilled material
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Local Exhaust Ventilation Discharge to atmosphere
Hood
Ducting
Filter
Fan
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Types of Ventilation
Enclosed
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Types of Ventilation
Hood
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Lip Extraction
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Ducted System
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Sawdust Extraction
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Machine Shop Extraction
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Portable Extraction
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Dilution Ventilation Vent Extract or Fan
Air drawn from clean air supply Fan ???
Contaminant
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When Dilution Ventilation may be used • • • • • • • •
Very low toxicity substance Steady rate of release Small quantity of contaminant Not practicable to use LEV Rate of evolution known Non specific point of release Type of contaminant (not dust) Heat loss or gain not a problem
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Measurement of Health Hazards 1) Initial appraisal 2) A basic survey 3) A full survey
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Measurement of Health Hazards 1) Initial Appraisal •
What substances are being used
•
What are their hazards
•
Do they have Occupational Exposure Limits
•
Where are they used
•
Who could be affected by them
•
How could they be released
•
If RPE or other forms of PPE is necessary
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Basic Survey 1) Smoke tube 2) Dust lamp Lamp - either traversed by hand to illuminate dust source or mounted on a stand
Dust cloud
Observer, or camera, viewing towards lamp whilst shielding eyes from glare
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Pumps and Stain Tubes
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Chemical Stain Detector Tube (Grab Sampler)
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Stain Detector Tube: Advantages • Cheap • Simple to use
• Immediate result • Useful during emergencies e.g. spillages • Good for rough reading of hazard
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Stain Detector Tube: Disadvantages a) Contaminant must be known b) Rough guide – within 20% accuracy band c) Reading a specific moment d) Results depending on positioning e) May be affected by other substance
© TWI Gulf WLL 2008
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FULL SURVEY Two principal methods of longer term sampling are :
a) Direct reading instruments b) Indirect reading instruments
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Constant Monitor
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Passive and Active Samplers
Passive Sampler
Active Sampler
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ENVIRONMENTAL PROTECTION
• Climate change • Ozone depletion (CFC) • Acid rain burn fuels produce polluting gases. (especially Nitrogen Oxides and Sulphur Dioxide) react with the tiny droplets of water in clouds to form Sulphuric and Nitric Acids.
• Usage of Natural Resources
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Industrial effects on the Environment Waterways and rivers poisoned Land becoming unusable Polluting Activities include:
Untreated effluent allowed to run away Chemicals used on farms leak into waterways Poor handling of chemicals
Inadvertent spillage
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What is Pollution Pollution is the release into or onto air, water, or land of any substance which is capable of causing harm to man or any other living organisms supported by the environment Harm includes: Harm to the health of human beings including offence to the senses Harm to other living organisms Harm to the quality of the environment, including the air, water or land Damage to property
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Pollution Types 1) Air Pollution Discharges in the atmosphere etc
2) Water Pollution Leakages from storage tanks etc
3) Land Pollution Dumping of hazardous wastes, etc.
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Pollution Control Strategy 1) Prevention: Preventing pollution by having good systems in place
2) Reduce: By changing the process e.g. reduce waste
3) Respond: Ensuring a rapid response to incidents such as spillages
4) Recover: Reviewing systems in places where problems have occurred
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Emergency Planning Procedure
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 Hierarchy PREVENT
REDUCE
RE-USE RECOVER DISPOSE
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Storing Waste
• Storage area of suitable size
• Storage area suitable location • Storage area clearly labelled • Individual containers clearly labelled • Different types of waste stored separately • Incompatible wastes never stored together • Storage kept to minimum • Protect wastes from elements if necessary • If necessary protect storage area with bunds • No hazardous waste in general waste skips • Ensure storage area secure
