Chemical Hazards

1
Chemical Hazards

• BOHS Series

2
December 3rd 1984
3
Bhopal Gas Disaster

• The Union Carbide Pesticide Plant in Bhopal,
  released 40 tons of Methyl Isocyanate (MIC) gas,
  killing between 2,500 to 5,000 people in the
  early hours of the morning.
• The Worlds worst Industrial Disaster

4

• The gas being heavier than air, started entering
  into the homes of the unwary population. Many who
  panicked and ran out also got crushed in
  stampedes.
• Around 500,000 were estimated to be exposed to
  the gas around 20,000 have died as a result.
  Over 120,000 continue to suffer from the from the
  effects of the disaster.

5

• Doctors and Hospitals were unaware of the nature
  of the Gas, nor were they informed of the proper
  treatment of the inhalation of MIC gas, being
  merely asked to give cough medicine eye drops.
• If they were informed about the same, proper
  treatment could have been instituted a lot of
  lives could have been saved.

6
Red Page in Annals of Occupational Health

• The Bhopal disaster brought into sharp focus the
  unprecedented potential of hazardous chemical
  release in terms of loss of life, health, injury
  and evacuation.
• It created a compelling evidence to approach
  disaster management and chemical safety
  holistically.
• The disaster brought in its wake, an era of
  restructuring and inducting new hazardous
  chemical control systems and procedures all over
  the world

7

• There have been many more such incidents of a
  relatively minor nature. One such was a Petroleum
  tanker accident on the highway near Mumbai.
  Spillage of the chemical on to the road came to
  the attention of the local impoverished tribal
  population, which started collecting the liquid,
  presuming it to be cooking fuel. A spark led to a
  conflagration consuming the lives of innocents.
• Such incidents brought into focus the
  vulnerability and the need for Risk assessment of
  transportation of Hazardous chemicals.

8

• Another frequent accident occurs when workers
  descend into empty confined spaces such as
  disused Wells, Food silos, Sewage channels etc,
  due to presence of noxious gases such as H2S
  CO.
• Many a lives have been lost and even those who
  tried to save the victims, due to lack of
  knowledge, have fallen prey to the same gas
  exposure.

9
Post Bhopal Gas Disaster

• Factories Act was amended to assign
  responsibility for workplace safety to the
  Occupier.
• Environment Protection Act was introduced in
  1986.
• The Manufacture, Storage Import of Hazardous
  Chemicals Rules,1989.
• The Chemical Accidents, Emergency Planning,
  Preparedness and Response,1996 introduced.

10

• India at present is achieving new milestones,
  major economic breakthroughs and moving ahead
  towards the vision of a developed nation. A
  sustained industrial growth including progress of
  the chemical sector is crucial to attaining this
  goal.
• The growth of the chemical sector has led to
  increase in the manufacture, storage and use of
  Hazardous chemicals (Hazchem) resulting in
  enhanced threats of accidents. Occurrence of
  accidents remains a cause of concern.

11

• The Indian Chemical Industry contributes to 6.7
  of the GDP.
• Indian Fertilizer Industry is the fourth largest
  in the world.
• Largest manufacturer of Pesticides in Asia second
  only to Japan.
• Indian Pharmaceutical industry is the largest in
  the developing world

12

• There are around 1790 Major Accident Hazard units
  in the country, handling large number of
  chemicals as raw materials, in processes,
  products and wastes with flammable, explosive,
  corrosive, toxic and noxious properties.
• Handling of large quantities of hazardous
  chemicals in installations, isolated storages and
  during transportation, poses grave risk of sudden
  release of copious quantities of toxicants. This
  may adversely impact both the communities in and
  around the area and the environment.

13
(No Transcript)
14
Impact of a chemical Disaster
15

• A chemical substance is a material with a
  definite chemical composition.
• New chemicals are being discovered daily at
  last count there are about 30 million chemical
  compounds

16
Toxicology

• Toxicology is the science concerned with poisons
  and how they affect the body.
• The main factors which determine the Toxicity of
  a substance are
• Chemical Composition- Some more poisonous than
  others
• Physical State-More toxic in soluble form than
  gas
• Amount
• Concentration
• Particle Size -especially when inhaled
• Routes of Absorption- Inhaled, Skin Contact or
  Ingestion.
• Presence of other poisons -Additive effects
• Duration of Exposure

17
Duration of Exposure to Chemicals

• Acute - Short Mins to Hrs
• Sub acute - Longer up to 90 days
• Chronic - Prolonged /Repeated over days, months
  years.

18
Measurement of Toxic Substances

• Threshold Limit value (TLV) Time weighted
  (average) concentration of an airborne substance
  to which workers could be safely exposed over an
  Eight hour working day throughout a life time.
• Maximum Allowable Concentration (MAC) Peak or
  Maximum conc. of an airborne substance to which
  workers could be safely exposed.
• Biological Limit values (BLV) Concentration of
  the substance in body fluids such as blood
  urine below which no toxic effects should occur.

19
Susceptibility to Toxic Chemicals

• Genetic factors
• State of Health
• Hypersensitivity or Allergy
• Personal Hygiene other personal habits such as
  Smoking etc.
• Pregnancy lactation.

20
Effects, Metabolism Excretion of Poisons

• Local- contact site such as Skin, URT
• Systemic Organs other than portal of entry
• In general, effects are on the metabolic
  processes of the body, especially enzymes. Others
  combine with substances essential for metabolism
  eg-CO

21

• Poisons are detoxified in different organs
  notably the Liver.
• Excretion takes place thro gut, urinary tract,
  skin or lungs. May also pass thro placenta
  milk.
• Dose -Effect Dose response demonstrate the
  response between the dose and the magnitude of
  effect.

22
Hazards

• Skin Irritation
• Eye Irritation
• Inhalation Effects
• Ingestion Effects
• Carcinogenicity
• Mutagenecity

23
Nature of Chemicals

• Inorganic and organometallic Substances-
  Antimony, Arsenic, Barium, Beryllium, Cadmium
  Chromium compounds, Fluoride, Lead, Manganese,
  Mercury, Nickel etc.
• Organic Chemicals - Aliphatic Hydrocarbons such
  as Cyclohexane, n-Hexane, Methyl pentane
• Aromatic Hydrocarbons such as Benzene, Styrene,
  Toluene Xylene.
• Halogenated Hydrocarbons - Halothane,
  Trichloroethylene Vinyl Chloride.
• Amino Nitro derivatives - Aniline,
  Nitroglycerine, Trinitrotoluene

24

• Alcohols, Glycols derivatives- Ehtylene glycol,
  Methanol
• Cetones- Acetone
• Aldehydes-Formaldehyde
• Amides Phenols
• Asphyxiants such as Acrylonitrile, Carbon
  Monoxide,Cyanide Aliphatic Nitriles.
• Pesticides such as Baygon, Carbaryl,
  Chlorphenoxyacetic acid derivatives

25

• DDT, Dieldrin, Endrin, Hexachlorbenzene
• Carbamate Insecticides
• Lindane
• Organophosphorus esters
• Parathion
• Mutagenic and carcinogenic Substances
• Others such as Carbon Disulfide,
  Diethylstilboesterol Ethylene Oxide

26
LeadInorganic Organic

• Inorganic Lead -
• Mining Smelting
• Lead Paint
• Lead Storage Batteries
• Pottery enamelling glazing
• Polyvinyl Plastics-Lead stabilisers
• Glass manufacture
• Fire arms

27
Effects of Lead Exposure

• Peripheral Neuropathy
• Anaemia
• Nephrotoxicity
• GI Spasm
• Treated with Chelating agents such as BAL, EDTA
  Penicillamine.

28
MercuryInorganic Organic

• In Scientific Measuring Instruments-Thermometers,
  barometers,Transformers, Rectifiers
• Mercury Vapour Lamps Storage batteries
• Amalgams for Dental use Jewellery
• Seed Dressings as Pesticides

29
Effects of Mercury Exposure

• Miamata Bay,Japan- (Untreated Inorganic Mercury
  released into sea waters-contaminated Fish.)
• Stomatitis, Gingivitis
• CNS Dysfunction
• Erethism
• Tremors
• Chronic Nephritis

30
Other Metals

• Phosphorus - Phossy Jaw (matches)
• Arsenic - Smelting, Pesticides, Weed Killer,
  Metal smelting, refining, in manuftrng of
  chemicals electronic equipment- Irritant,
  Peripheral Neuropathy Haemolytic.
• Manganese - Dry Electric batteries- Parkinsons
  Syndrome, Psychosis, Pneumonitis
• Cadmium - Used as alloy in Welding, batteries,
  Dentistry, pigments,paints,pesticides-
  Nephrotoxic, Emphysema.
• Nickel- Dermatitis
• Chromium- Chrome Ulcers, Necrosis of Nasal Septum

31
Carbon CompoundsAliphatic aromatic

• Aliphatic -Methyl Alcohol, Tetrachlorethane,
  Carbon tetrachloride, Trichlorethylene Glycols
• Aromatic - Benzene, Toluene, Xylene etc.
• Exposure- Degreasing, Metal Machining, painting,
  Welding, Wood working Printing.

32
Health Effects

• Occupational Dermatitis
• CNS depressants
• CVS disturbances esp CS2
• Nephro toxic
• Bone Marrow Depression Leukemia
• Carcinogenesis
• Chromosomal aberrations

33
PesticidesPoisoning through skin absorption GI
tract.

• Insecticides Fungicides - - Pyrethrum
  Pyrethrins (Mosquito Coils), Organochlorine
  Compounds such as DDT, Lindane, Dieldrin
  Aldrin, Organophosphate compounds such as
  Parathion, Dichlovos, Carbamates Organic
  Mercurials.
• Herbicides - Arsenicals, Dinitrophenol,Di nitro
  Ortho cresol,Phenol herbicides, Paraquat, Diquat,
  Phenoxy herbicides.
• Rodenticides Fumigants -Calcium Cyanide, Methyl
  bromide, Phosphine, Anticoagulants.

34
GasesInert, Irritant gases with Systemic
Effects

• Inert gases - Act by displacing O2 -Anoxic
  Anoxia, eg Methane
• Irritant Gases - Flourine its compounds,
  Ammonia, Sulphur Dioxide, Ozone, Phosgene.
• Gases with Systemic effects- Carbon Monoxide
  (Toxic Anoxia),Carbon Disulfide (Chemical
  Anoxia), Hydrogen Cyanide Cyanide Salts,
  Acetylene
• (Cyanide has a Bitter almonds smell whilst
  Benzaldehyde has a sweet almonds smell)

35

• Halogen Gases like Cl2,Br,Flourine,Iodine have an
  Irritant effect on URT.
• Flourine could cause Flourosis, Fits Coma.
• Ammonia- Irritant, Brochospasm, Pulmonary Oedema
  Respiratory Arrest
• Sulfur Dioxide So2 - Lassitude, Chronic
  Bronchitis, Loss of Smell.
• Ozone-Irritant, emphysema, Pulmonary Fibrosis.
• Phosgene-Pulmonary Oedema, Fibrosis Emphysema

36

• Carbon Monoxide - Anoxia, Headache, Cough,
  Paralysis, Sensory Loss, Parkinsonism, Death.
• Hydrogen Sulphide - Irritant, Loss of Smell,
  Giddiness, Unconsciousness, Death.
• Hydrogen Cyanide - Extremely Poisonous. Bitter
  Almond Smell, Dermatitis, Headache Motor
  Weakness at low conc. Breathlessness Coma..
• Acetylene - Fume Fever

37
General Principles for Prevention Control of
Exposure at Worksite

• Substitution
• Segregation
• Enclosure
• Ventilation
• Wet Methods
• Personal Protective Devices
• Monitoring of Work Environment
• Monitoring of Exposed Workers
• Education Supervision
• Enforcement
• Emergency Measures

38
Management of Poisoning CasesBasic Principles

• Removal from further Exposure / Evacuation
• Detoxification eg Chelating agents
• Supportive Therapy - Oxygen IV Fluids.

39
(No Transcript)
40

• Conclusion
• Need to increase Awareness
• About the Industries in your area
• About the nature of Chemicals being used, stored
  and transported
• About their hazards and treatment procedures in
  the event of exposure.

41
(No Transcript)
42
Thank youAcknowledgements Dr Chaitanya S
Gulvady