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NEBOSH
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, Acids, Alkalis, Asbestos Asbestos Biological: HIV Virus, Legionella, Bacteria Ergonomic: Posture problems, Fatigue problems, Fatigue Psychological: Stress, Shock Shock,, Anxiety
NEBOSH
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 viruses Diseases caused by biological agents include: • Legionnaires disease
a type of pneumonia or lung lung infection 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 t ransmitted bite from a wild w ild infected animal
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Biological Hazar H azards ds Control Measures 1) 2) 3) 4)
Cleani Cle ning ng / Dis Disin inffect ctin ing g Water tr trea eatm tmen entt prog progrram amme mess Vermin control A pest animal prohibited, controlled Proc Pr oced edur ures es for ha hand ndli ling, ng, co cont ntai ainm nmen entt & disposal 5) Person ona al hygiene 6) Immunisation to build resistance to specific infections 7) Healt lth h su surv rve eillance strategies and methods to detect and assess systematically the adverse effects of w ork on the health of workers.
8) Speci ciffic training 9) PPE
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PHYSICAL FORMS OF HAZARDOUS HAZARDOU S SUBST SUBSTANCES ANCES • • • • • • • •
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 Hazar dous Substances Symbols (2)
Harmful:
Substances which if swallowed, inhaled or penetra penetrate te 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 Hazar dous Substances Symbols (3)
Toxic: Poisonous substances which in low quantities may cause death, acute chronic damage to health e.g. Lead, Mercury 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 Hazar dous 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) Inje Inject ctio ion n (Dir (Direc ectt 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 Response: How 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 Effect Effectss 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 w hich causes reddening, soreness, cracking and bleeding of exposed 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 Pre-employ ment screening Information, instruction and training
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Target Organs A Target Organ Organ is defined defined as: An organ within the human body body on which a specific toxic material exerts its effects.
Lungs
Brain
Asbestos,, Coal dust Asbestos
Lead, Mercury
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Target Organs Brain – Brain – lead Nasal passages – passages – organic solvents Lungs – Lungs – asbestos, asbestos, chlorine, carbon dioxide, ammonia, isocyanates, silica, organic solvents, legionella
Eyes – Eyes – ammonia
Kidneys – leptospirosis
Liver – Liver – hepatitis hepatitis Blood – carbon Blood – carbon monoxide Skin - detergents, isocyanates, mineral oils, acids, alkalis, organic solvents
Nerves – 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 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 pro Stop roce ces ss Remo Re move ve em empl ploy oyee ees s fro from m area area Make ar area sa safe Inve In vest stig igat ate e ca caus use e Asse As sess ss ex exis isti ting ng co cont ntro rols ls Moni Mo nito torr pro proce cedu dure res s Chec Ch eck k wor worke kers rs he heal alth th Reco Re cord rd in inci cid dent
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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 Ammonia: colourless gas with w ith a pungent odour • Irritation to the eyes and upper respiratory tract • Used in printing and fertilisers Chlorine:: A greenish Chlorine greenish gas with w ith 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 kidneys and liver 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 s • Asbestosi
(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’ r’s s lu 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) • Gastrointestin Gastrointestinal al (Ingestion) • Skin (Absorption) • Cellular mechanism (Injection)
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Respiratory (Inhalation) Defences • NOSE : Wetness & nasal hair • RESPIRATOR RESPIRATORY Y TRACT : Natural Nat ural reflexes activate sneezing and coughing • CILIARY ESCALATOR – ESCALATOR – A 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 enzymes and bacteria bacteria Vomit and diarrhoea
Skin Defences • • • •
Sebum Sensory nerves Melanin Blisters, rashes, inflammatio inflammation n
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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 manufactur manufacturer/supplier er/supplier Composition/information Composition/informat ion on ingredients Hazard identification Health effects First Aid measures Fire fighting measures Accidental release measures Handling and stor storage age Exposure controls
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Manufacturers Safety Data Sheet (2) Personal Protective Equipment Environmental/Disposal
considerations Physicall and chemical properties; Physica Stability and reactivity; Toxicological information; Ecological informa information; tion; Disposal considerations; Transport information; Regulatory informa information; tion; 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
S2 Keep out of the reach of children
R20 Harmful by inhalation R30 Can become R30 Can highly flammable in use R45 May cause cancer
S20 When using do not eat or drink S25 Avoid contact with eyes S41 In case of fire S41 In 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 concentr concentration ation 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 might be harmed harmed and how
Operators, Others, Pregnant and young worker
3) Evaluate the Health Health risk & existing precautions
Likelihood and Severity
Existing control measures
Judgement about need for further control measures
4) Re Reco cord rd the the si sign gnif ific ican antt find findin ings gs
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 Supervisi on reports improper use of equipment Enforcement actions Compensation claims
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Prevention Preve ntion and Control C ontrol 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 Maintenance pattern, Hygiene, Housekeep Housekeeping ing
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 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 Sys System tem
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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) Init Initia iall Appr Apprai aisa sall •
What substances are being used
•
What are their hazards
•
Do they have Occupational Exposure Limits
•
Where are they used
•
Who could be aff affected ected 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: Tube: Advantag Advantages es • Cheap • Simple to use • Immediate result • Useful during emergencies e.g. spillages • Good for rough reading of hazard
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Stain Detector Detector Tube: Tube: Disadvantages a) Co Cont ntam amin inan antt mus mustt be kn know own n b) Rough guide – – within within 20% accuracy band c) Re Read adin ing g a spe speci cifi fic c mom momen entt d) Res Result ults s dep depend ending ing on pos posit ition ionin ing g e) May be af affec fected ted by oth other er sub substa stance nce
© TWI Gulf WLL 2008
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FULL SURVEY Two principal methods of longer term sampling are :
a) Direct reading instruments b) Indir ire ect readin ing g instrum ume ents
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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 fuels produce polluting gases gases.. (especially Nitrogen Oxides and Sulphur Dioxide) react with the tiny droplets of water water in in clouds to form Sulphuric Sulphuric and and Nitric Acids. 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 environmen environmentt 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 Control Strategy 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 • Differe Different nt types of waste stored separately • Incompatibl Incompatible e 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
