2. Chemical hazards
• Hazard: Any situation that has
potential/capability to cause Injury/harm to
the worker, damage to the property,
Loss/contamination to the environment.
• Risk: Any situation that has probability to
cause Injury/harm to the human, damage to
the property, Loss/ contamination to the
environment.
3. Chemical hazards
• Accidents: These are unplanned, unwanted
and improper occurrence involving
injury/harm to the employee, damage to the
property, Loss/contamination to the
environment.
4. Chemical hazards
Types of Chemical Hazards
Irritant chemicals
Sensitizers
Toxic Chemicals
Asphyxiates
Anesthetic and Narcotic
Systematic poisons
6. Chemical hazards
• Irritant chemical: Primary irritant cause
inflammation is one of the body’s defense
mechanisms. It is the reaction of tissue to harm
which in sufficient to kill the tissue and is typified by
construction of the small vessels in the affected area,
dilution of the blood vessels, increased permeability
of vessel walls, and migration of the white blood cell
and defensive cells to the invading harmful chemicals
i.e. sulphur dioxide may made a blistering effect on
Upper respiratory.
7. Chemical hazards
• Sensitizers: generally sensitizers may not on
first contact result in any ill effects, although
cellular changes can be induced and the
body’s immune system affected (some
chemicals may act as primary irritants as well
as sensitizers).
8. Chemical hazards
• Anesthetic and Narcotic: anesthetic and
narcotic e.g. hydrocarbons and certain
derivatives such as the various chlorinated
solvents or other, exert a depressant action on
the central nervous system i.e. Aliphatic
alcohols, petroleum etc.
9. Chemical hazards
• Systematic poisons: Systematic poisons attack
organs other than the initial site of contact. The
critical organs are the kidneys, liver, blood and
bone marrow. Many halogenated hydrocarbons
are effects the Visceral organs in Hematopoietic
(i.e. blood-forming system) Nervous system.
10. Chemical hazards
• Respiratory fibro gens: The hazard of
particulate matter is influenced by the toxic
and size and morphology of the particles. The
critical size of dust (and aerosol) particles is
0.5 to 7 µm, since these can become
deposited in the respiratory bronchioles and
alveoli. i.e. Free crystalline silica.
11. Chemical hazards
• Carcinogens: Cancer is a disorder of the body’s
control of the growth of cells. The diseases
may be a genetic or influenced by life style or
exposure to certain chemicals, termed
carcinogens i.e. Coal tar pitch dust, Asbestos
etc.
12. Chemical hazards
• Toxic Chemicals: Chemicals having following
values of acute toxicity and which, owing to
their physical and chemical property, are
capable of producing major accidents hazards.
13. Chemical hazards
• TOXICITY: IDLH: the Immediately Dangerous to
Life and Health are not occupational exposure
limits similar to the TLV. They were developed by
National Institute of Occupational Safety and
Health to guide respirators selection. It is that
maximum level of concentration of an air borne
contamination from which one could escape
within 30 minutes without any impairing
symptoms or any irreversible health effects. It is
reported in ppm or mg/m3.
14. Chemical hazards
• TLV (THRESHOLD LIMIT VALUES): The two or more
hazardous substances are present, their combined effect
rather than that of individually, should be given primary
consideration. The effects of the different hazards should be
consideration as additive.
• Time-Weighted Average: The TLV may be a Time-
Weighted Average (TWA) figure that would be
acceptable for 8 hours exposure. For some
substances such as an extremely irritating one, a
Time weighted Average concentration would not be
acceptable.
15. Chemical hazards
• TLV-STEL: Some substances have a Short-Term
Exposure Limit. The 8 hours TLV remains
within the limit. Such limits were assigned to
substances exerting toxic even over a short
period of time. STEL exposure should not be
more than 4 per day with at least 60 minutes
gap between successive exposures.
16. Chemical hazards
• LTEL (Long-Term Exposure Limit): Long-term
exposure limit are concerned with the total
intake of contaminants (or contaminants) over
a long period.
• LD 50 for acute local Toxicity: It is that dose of
the substance administered which is most
likely to cause death within in one half of both
male and female young adult rats. The result
is expressed in mg per kg body weight.
17. Chemical hazards
• LC 50 for acute toxicity in Inhalation: It is that
concentration of vapor, mist, or dust which,
administered by continuous inhalation to both
male and female young adult rat for one hour
causes death within 14 days in one half of the
animals tested.
• LC Lo (Lethal Concentration Low): It is the lowest
concentration of a substance in air other than
LC50 which has been reported to have caused
death in humans and animals.
19. • LOWER EXPLOSIVE LIMIT: The maximum concentration of a
gas, vapor, mist or dust in air at a given pressure and
temperature that will propagate a flame when exposed to an
efficient ignition source. Generally expressed as % by volume
for gases and vapors, and as mg/m3 for mists or dusts.
• MAXIMUM EXPOSURE LIMIT: The maximum concentration
of an airborne sub-stance, averaged over a reference period,
to which employees may be exposed by inhalation under any
circumstance. Thus, exposure to a chemical assigned an MEL
must be low as is reasonable practicable and, in any case,
below the MEL.
• UPPER EXPLOSIVE LIMIT(UEL): The maximum concentration
of gas, vapor, mist or dust in air at a given pressure and
temperature in which a flame can be propagated.
20. Chemical hazards
• Risk Control: Exposure to chemicals, resulting in toxic
effects or oxygen deficient -atmospheres, may arise in
a variety of industrial situations. A summary of
common sources, clearly this is not exhaustive since
exposure may result whenever materials are mixed,
machined, heated dispread (or) otherwise processes
(or) used. The precautions naturally vary in each case.
For example, to avoid improper admixture of chemical
will require. Adequate training, instruction and
supervision of workers Identification of chemicals by
name and code numbers Segregated storage of
incompatible substances.
21. Chemical hazards
• HAZARD RECOGNITION The toxicity of a substance is its
capacity to cause injury once inside the body. The main
modes of entry into the body by chemicals in industry are
inhalation, ingestion and absorption through the skin.
Gases, vapors, mists, dusts, fumes and aerosols can be
inhaled and they can also affect the skin, eyes and mucous
membranes. Ingestion is rare although possible as a result
of poor personal hygiene, subconscious hand-to-mouth
contact, or accidents. The skin can be affected directly by
contact with the chemicals, even when intact, but its
permeability to certain substances also offers a route into
the body. Chemicals accorded a ‘skin’ notation in the list of
Occupational Exposure Limits may also arise via skin
lesions.
22. Chemical hazards
• Other Chemical Hazards:
• Class 1 Explosive
• Class 2 Gases compressed
• Class 3 Flammable Liquids
• Class 4 Flammable Solids
• Class 5 Oxidizing (5.1 Oxidizing substances, 5.2
Organic per Oxides)
23. • Class 6 Poisonous (toxic) 6.1 poisonous (toxic),
6.2 Infectious substances.
• Class 7 radioactive
• Class 8 corrosive
24. Chemical hazards
• Flammable: these are the substances which
may get ignited by source of ignition i.e.
alcohol, acids etc.
• Explosive: These substances may get explode
due source of ignition, temperature increase
i.e. ammonium nitrite.
25. Chemical hazards
• Corrosive: These are the chemicals which
corrode the substance while contact i.e. Acids.
• Oxidizing: These are the chemicals which may
create depression of oxygen in the atmosphere.
• Reactive: These are the substances which react
with other substances i.e. Aluminium
borohydride (Al(BH4)3) if mix with water H2o it
will get explode.
26. Chemical hazards
• Radioactive: These are the substances which
may generates radiation in the atmosphere
i.e. potassium-40, carbon-14
