chemical

1. Chemical Handling/Hazards
All Chemicals Are Hazardous
• PDO has 785 chemicals
• Rejected 22
• Carcinogens 7 (e.g, Benzene, Crystalline Silica, Asbestos)
• A cigarette contains >3800 – 40 Carcinogens

2. 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.

3. 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.

4. • 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.

5. 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

6. Physical Classification
Solids Aerosols
Liquids Vapours
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.

7. 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.

8. 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).

9. 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.

10. 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.

11. 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.

12. Toxicity
Toxicity Depends on : Amount + Duration
Exposure
or
effect
Dose
Response
of
%
dead
LD50 LC50
(other routes)- (air)
Dose (single exposure)
50

13. Health Hazards
1. Irritant Severe Irritation
Irritation
Slight 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.

14. Exposure Route
Lung
Ear Eye
Nose
Mouth
Musculo-
skeletal
Skin
Whole body

15. Target Organs
Lung Heart
Digestive tract
Liver
Kidneys
Ear
Eye
Skin
Nose
Mouth
Reproductive
system
CNS

16. 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

17. 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)

20. National Fire Protection Association
Hazard Classification
0
W
2
4
Flamability
Reactivity
(Stability)
Health
Water