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Chemicals

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					Chemicals
Forms
 Chemical health hazards may be divided
 into the following categories:
  – Toxic, including carcinogenic;
  – Corrosive & irritant;
  – Dermatitic/sensitising
Forms
 Chemical hazards can also be classified
  according to physical state:
  –   Liquids (fluids)
  –   Dusts (solid particles)
  –   Fumes (fine solids, often metallic)
  –   Mists (finely suspended droplets)
  –   Vapours (gaseous form of a solid or liquid)
CHIP
 Classify substance (Approved supply list)
 Assign categories of danger & risk phrases
 Provide safety data sheet
 Label
 Safe packaging
 Child-resistant closures
 Tactile danger warnings
 Mention hazards in advertisements
Health Effects of Hazardous
Substances
 Under CHIP, suppliers must classify dangerous
  chemicals under one or more of the following:
   –   Very toxic
   –   Toxic
   –   Harmful
   –   Corrosive
   –   Irritant
   –   Sensitising
   –   Carcinogenic
   –   Mutagenic
   –   Toxic for reproduction
Safety Data Sheets
 Composition and/or     Physical & chemical
  ingredients             properties
 Hazards                Stability & reactivity
 First aid              Toxicological info
 Fire fighting          Ecological info
 Accidental release     Disposal
 Handling & storage     Transport
 Exposure controls      Regulatory & other
 Personal protection     info
Lead
 Most dangerous as a fume or dust
 Target organs:
  – Central nervous system
  – Gastrointestinal tract
  – Blood & blood-forming organs
  – Muscles of wrist or foot
  – Gums
 Symptoms affect gastrointestinal tract,
  nervous system and blood
Mercury
 Target organs:
  – Central nervous system & brain
  – Kidneys
 Symptoms affect central nervous system
  with personality changes
 Workers at risk:
  – Dentistry
  – Thermometers, barometers, electrical
    switchgear
Benzene
 Volatile liquid absorbed by inhalation and
  skin contact
 Target organs:
  – Central nervous system
  – Blood-forming organs
 Symptoms are narcosis, anaemia and
  leukaemia
Phenol
 Corrosive & toxic substance absorbed by
  the skin
 Systemic toxin affecting central nervous
  system
 Symptoms affect central nervous system,
  liver and kidneys
Trichloroethylene
 Harmful by inhalation, prolonged skin
  contact & ingestion
 Affects central nervous system, skin and
  respiratory tract
 May be an animal carcinogen
Siliceous Dust
 Inhalation of dust causes fibrosis of lungs
 Symptoms caused by reduced lung function,
  breathlessness, heart strain and possibly
  death
Asbestos
 Inhalation of dust causes fibrosis of lungs
 Symptoms caused by reduced lung function,
  breathlessness, heart strain & possibly death
 Risk of lung cancer in fibrotic regions
Carbon Monoxide
 Invisible gas absorbed by lungs into blood
  stream, combining with haemoglobin and
  inhibiting oxygen transport
 Oxygen starvation causes loss of
  consciousness
Carcinogens
 Produce malignant tumours by affecting cell
  functioning
 Long latency period and no threshold of
  harm
 Examples:
  – Tars (skin cancer)
  – Asbestos (lung cancer & mesothelioma)
  – Vinyl Chloride Monomer (angiosarcoma)
Corrosive Substances
 Acids destroy living tissue and cause severe
  burns; examples include nitric and sulphuric
  acid
 Ammonia is a corrosive alkaline gas,
  soluble in water, which can cause severe
  burns by liquid contact or inhalation
Dermatitic Hazards
 Dermatitis: non-infectious inflammatory
  condition of the skin caused by contact with
  chemical, physical or biological agents
 Classified into two forms:
  – Contact: caused by contact with primary
    cutaneous irritants (greases, mineral oils,
    solvents);
  – Sensitisation: Caused by cutaneous sensitisers
    (rubber additives, nickel compunds, hardwood
    dust)
Sensitisers
 Chemical agents able to produce an allergic
  reaction in certain individuals
 Production of antibodies triggers an allergic
  reaction each time person is subsequently
  exposed to very small quantities of the
  causative agent
Sensitisers
 Respiratory System:
  – Results in asthma
  – 2 principle types of agent:
      • Antigens, such as flour, grain & shellfish protein
      • Substances such as isocyanates and platinum salts
 Skin:
   – Results in dermatitis
   – Skin reaction will occur whenever there is
     further contact with sensitising agent (common
     sensitising agents are isocyanates)
Sensitisers
 Chemical agents able to produce an allergic
  reaction in certain individuals
 Production of antibodies triggers an allergic
  reaction each time person is subsequently
  exposed to very small quantities of the
  causative agent

				
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