A chemical accident is the unintentional release of one or more hazardous substances which could harm human health or the environment. Chemical hazards are systems where chemical accidents could occur under certain circumstances. Such events include fires, explosions, leakages or releases of toxic or hazardous materials that can cause people illness, injury, disability or death.

1. CHEMICAL DISASTERS
• A chemical accident is the unintentional release of
one or more hazardous substances which could
harm human health or the environment. Chemical
hazards are systems where chemical accidents
could occur under certain circumstances. Such
events include fires, explosions, leakages or
releases of toxic or hazardous materials that can
cause people illness, injury, disability or death.

3. CHEMICAL DISASTERS
• While chemical accidents may occur whenever
toxic materials are stored, transported or used, the
most severe accidents are industrial accidents,
involving major chemical manufacturing and
storage facilities. The most significant chemical
accident in recorded history was the 1984 Bhopal
disaster in India, in which more than 50,000 people
had died after a highly toxic vapour, (methyl
isocyanate), was released at a Union Carbide
Pesticides factory.

4. Chemical disasters may arise in number of
ways
• Process and safety systems failures
- Human errors
- Technical errors
- Management errors
• Induced effect of natural calamities
• Accidents during the transportation
• Hazardous waste processing/ disposal
• Terrorist attack

5. EFFECTS
• Chemicals can affect the skin by contact or
the body either through the digestive system
or through the lungs if air is contaminated
with chemicals, vapours, mist or dust. There
can be an acute (immediate) effect, or a
chronic (medium to long-term) effect from
the accumulation of chemicals or substances
in or on the body.

6. TOXIC POLLUTION
• When chemicals are released into our environment
and disrupts the balance of our ecosystems,
threatening our health, polluting the air we breathe
and contaminating our food.
• There are many sources of chemical pollution. Our
technological advances have made us a species
largely reliant on chemicals and these chemicals are
toxic to life and our environment.

7. SOURCES OF CHEMICAL POLLUTION
• Agriculture
• Transportation
• Industry
• Anthropogenic activities

8. Pesticides
• The crop plants are infected by many disease
causing organisms called as pests.
• They cause damage to crops, humans and
other animals.
• The insects, mice and other animals,
unwanted plants, fungi, micro organisms
such as bacteria and viruses.

9. Contd…
• The term pesticide refers to a substance or
mixture of substances that is meant to
prevent, destroy, repel or mitigate any pest.
• It includes the insecticides, fungicides and
other substances that re used to control the
pests.
• Some examples includes cockroach sprays,
insect repellents, tick sprays and powders.

10. Effects of pesticide pollution
• The soil becomes deficient in micronutrients.
• Deficiency of carbon content in soil results in
decrease in water and nutrient holding capacity.
• Increased usage of pesticides have caused
disorders of endocrine system, particularly the
thyroid, parathyroid, pituitary glands, kidneys,
etc..

11. ADVANTAGES
• The greatest benefit of using pesticides is
controlling the population of pest species.
• Pesticides help in eliminating the disease vectors to
plantation.
• Application of pesticides to crops leads to
agricultural augmentation i.e., the plants are able to
grow more healthily, as the pests can neither feed
nor lay eggs on them and cause damage.

12. DISADVANTAGES
• Pest resistance
• Toxic effects
• Effects of pesticides on humans

13. PRECAUTIONS
• Always read the label on the pesticides container
and follow the instructions while using it.
• The pesticide should be kept out of reach of
children.
• Smoking should be avoided while spraying.
• The body should be properly clothed from head to
toe to avoid exposure of the body to the harmful
chemicals.
• Hands should be thoroughly washed after using
the pesticides.