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 World’s worst Industrial Disaster
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.
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.
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
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.
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.
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.
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.
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
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.
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
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
Acute - Short Minutes to Hours Sub acute - Longer up to 90 days Chronic - Prolonged /Repeated over days, months & years.
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.
Genetic factors State of Health Hypersensitivity or Allergy Personal Hygiene & other personal habits such as Smoking etc. Pregnancy & lactation.
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
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.
Substitution Segregation Enclosure Ventilation Wet Methods Personal Protective Devices Monitoring of Work Environment Monitoring of Exposed Workers Education & Supervision Enforcement Emergency Measures
Removal from further Exposure / Evacuation Detoxification eg Chelating agents Supportive Therapy - Oxygen & IV Fluids.
ConclusionNeed 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.