Chemical Handling/Hazards

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Chemical Handling/Hazards

• All Chemicals Are Hazardous
• PDO has 785 chemicals
• Rejected 22
• Carcinogens 7 (e.g, Benzene, Crystalline Silica,
  Asbestos)
• A cigarette contains gt3800 40 Carcinogens

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Chemical hazards

• Chemicals are the most common and significant
  health hazards
• Chemicals can be hazardous for numerous reasons
  and can combine with other chemicals to make new
  hazards
• All hazards must be taken into account when using
  and storing chemicals.

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Objectives

• To
• Recognize chemical hazards commonly encountered
  in the field
• Explain warning properties of various chemical
  hazards
• Describe how to evaluate and control these
  hazards.

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• The degree of hazard associated with a particular
  chemical will depend on
• Its physical properties
• Its toxicity
• The way it is used
• The environment in which it is encountered.

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Chemical Handling/Hazards
Chemical hazards Liquids, Dust, Fume, Mist,
Vapour gas Modes of Entry Ingestion Skin
Absorption/eyes Inhalation Toxicity Ability of
the substance to harm the body and the manner in
which it harms the body Quantity Duration
Toxicity Dose The dose makes the poison
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Physical Classification
Chemicals may be found in solid, liquid, aerosol,
or gas and vapor form. The degree of danger
varies according to the form of the chemical and
the factors previously discussed.
Solids
Aerosols
Liquids
Vapours
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Solids

• Not all forms of a chemical pose a health hazard.
  
• For example, a lead pipe is not a significant
  health hazard.
• However, the lead can become a human health
  hazard if the pipe is sanded or welded, producing
  lead dust or fumes.
• The dust or fumes can become airborne and be
  inhaled, or it can leach into water and be
  ingested.

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Solids

• A chemical may be hazardous even in solid form.
• For example, individuals who are sensitized to
  nickel may develop dermatitis from skin contact
  with the metal.
• Fuming solids emit toxic vapors that may be
  inhaled.
• Some materials, such as pesticides, can evaporate
  directly from solid form.
• Some solids are not a hazard alone but become
  hazardous when they come into contact with other
  chemicals (e.g., acid in contact with iron can
  release hydrogen gas).

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Aerosols

• Aerosol is a term used to describe fine particles
  (solid or liquid) suspended in air.
• Examples of aerosols include dust, fumes, mist,
  fog, smoke, and smog.
• Knowing how various aerosols are generated will
  help you anticipate where aerosol hazards may
  exist in the field
• Aerosols may be a hazard to the eyes, skin, and
  the respiratory system.

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Liquids

• Many liquids are hazardous in contact with the
  skin. They either damage the skin or they are
  easily absorbed through the skin.
• chemicals that can damage or be absorbed through
  the skin and will have this effect on all skin,
  not just the hands.
• The degree of hazard associated with a liquid
  depends on its characteristics and how it is
  handled.

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Liquids

• For example,
• inhalation is the primary route for a chemical
  to enter the body. Its vapour pressure is
  important in determining the liquid degree of
  hazard.
• Liquids with a low vapor pressure may create a
  low airborne concentration.
• Liquids with a high vapor pressure may produce
  high airborne concentrations.
• The hazard level of an airborne concentration
  depends in part on the chemical's toxicity.

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Toxicity
Toxicity Depends on Amount Duration
Response of dead
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Exposure or effect
LD50 LC50 (other routes)- (air) Dose (single
exposure)
Dose
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Health Hazards
1. Irritant Severe Irritation Irritation Sligh
t or No effect 2. Toxic Effect High LD50
100ppm 3. Asphyxiant 4. Sensitiser 5.
Teratogenic (unborn child) 6. Mutagenic (Heritable
genetic defects) 8. Carcinogenic 9. Oil Acne
(Cutting Oil) 10. Particle size (Micron) 10
100 11. Photosensitiser (Irritant or Sensitiser
UV) Coal Tar Pitch
11.
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Exposure Route
Eye
Ear
Nose
Mouth
Lung
Musculo-skeletal
Skin
Whole body
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Target Organs
CNS
Eye
Nose
Ear
Mouth
Lung
Heart
Digestive tract
Liver
Skin
Kidneys
Reproductive system
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Personal Protective Equipment

• Depends Physical Form, (Solid, Gas, Liquid)
• Potential health effects (Irritancy - Toxicity)
• Quantity handled
• Method used
• Nominal Protection Factor
• Hazard Labelling
• Break Through Period
• Types Protective Clothing
• Gloves
• Goggles
• Shields
• Hearing Protection
• Respirator - Air Supplied
• Air Purified

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Control Measures

• Chemical Approval Panel?MSDS? (SHOC)
• Elimination
• Substitution
• Changed Method of work
• Engineering Control (extraction)
• Information, Instruction Training
• Personal Protection Equipment
• Monitoring
• Recovery Measures (Emergency Plan)

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National Fire Protection AssociationHazard
Classification
Flamability
2
0
4
Health
W
Reactivity (Stability)
Water