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Strategies for Chemical Disaster Management
Chemical Disaster
Alike other disasters, chemical disaster management has two major components, viz. (a) Disaster Risk Reduction and Management and (b) Emergency Preparedness, Response and litigations.

Various functions like site selection and site assessment, hazard inventory/characteristics and vulnerability/exposure analysis, Ecological Modelling and scenarios, disaster mitigation systems, CDM in multi-hazard framework, GIS & Remote Sensing Application, ICT Tools, Environmental laws and policies, Emergency Risk Assessment, Emergency planning, preparedness, incident command system, post-accident investigations, various tools like safety surveillance, safety audit, environmental audit, land-use planning, etc.

Globally accumulated experience of natural disasters such as earthquakes, floods, cyclones etc. can be used to keep ourselves prepared to face emergencies such as the outbreak of epidemics, the psychiatric trauma of loss of shelter and security or contamination of food and water. In contrast, the consequences of chemical disasters and their impact on environmental and health are almost unpredictable. There is usually no warning signal and hence very little time to prepare the community to face the grave consequences. More often than not, the cause effect relationship in a chemical disaster is difficult to establish and hence the initiation of measures for emergency treatment has to be done on arbitrary considerations. This can have an adverse influence on the post emergency rehabilitation scheme as well.

The decade 1974-84 witnessed an usually large number of industrial accidents involving hazardous chemicals: The flixborough explosion, the Beek disaster consequent on the release under pressussre of propylene, the Seveso disaster, the Mississagua accident due to collision of wagons of chlorine and propane, the Houston soill of anhydrous ammonia, the Sommerville, Massachussetts spill of phosphorous trichloride, the Mexico explosion involving liquefied gas and, the worse of all, the Bhopal Disaster of Dec 1984.

Various steps of chemical disaster risk management are categorized into five groups of following stages:
  1. Hazard and Risk Assessment:
  2. Prevention and Mitigation:
  3. Planning & Response:
  4. Integration into Mainstream:
  5. Integration into Development:
    • Integration of Chemical Disaster Risk Management Plan into Land-use and Development Planning using mapping based approach


Environmental systems analysis, modeling and scenario simulation are the activities employed under the steps listed above, and employ following hardware and software tools:
  • Atmospheric release: Dispersion, plume and concentration models
  • Ground release: Geo-hydrodynamic models, Liquid Flow models, Two-phase flow models
  • Release in water: Steam-flow models, 1-D and 2-D models for diffusion and dilution
  • Risk-contour development and Land-use models: GIS software
  • Consequence modeling
  • Risk Information system tools
  • GIS based emergency simulation, lay-out and land-use, emergency planning, response and resource management
Looking to the comprehensive risk management approach that involves the steps of different stages of disaster management cycle, viz. assessment, prevention, mitigation, preparedness, response, recovery and rehabilitation, following aspects are important to be envisaged in a holistic approach to chemical disaster management:
  • Involvement of all relevant stakeholders
  • Interdisciplinary approach in assessments, planning and organization of activities
  • Generation and effective management of databases, information and knowledge networking, with application of modern technologies
  • Integration of chemical disaster management in the holistic framework of disaster risk reduction and management
  • Mainstreaming chemical disaster risk management in regional planning and development
  • Integrated approach to capacity development through training, awareness, knowledge management
  • Voluntary arrangements, partnership and incentive based approaches for effective governance
Chemical Disaster
In order to effectively organize the preparedness and responses to likely chemical emergencies, an objective, systematic, written and applicable plan need to be in place at different levels, viz. the industry, local, district, state and Central level. Development of policy directives, guidelines and strategic tools, e.g. assessments (EIA, Audit, LCA, Risk Analysis, Multi-hazard vulnerability analysis), fiscal (PLI, Cess, Levi), market based (labeling, ISO), planning (on-site and off-site, carrying capacity based developmental planning, land-use governance, industrial estate planning, site selection), enforcement (law, rules, protocols), policy (industrial ecology,) and voluntary arrangements are to be made more integrated, practical and effective. Legislations and mechanisms at both the "book" level and also the "operational" level are equally important. A community centric approach to holistic risk management has been suggested in figure V.

A holistic risk management framework for chemical-disaster prevention and management, thus, is a multi-disciplinary state of affairs, involving expertise from hard and soft disciplines of environmental studies; as mentioned below: On-site emergencies are the chemical accidents that are controllable within the promises of the industry/installation boundary by the emergency management systems of the respective occupier within its own resources, internally or pooled in the proximity, and thus, without actively involving the State Government. Whereas, it is called off-site emergency when initially an on-site emergency emerges to an extent in size and intensity that it is beyond the capacity and resources at the occupier level (under On-site plan) and the Government is requested to take over the incident of the emergency. In such situations, District Collector acts as the Chief Incident Controller and an Off-site emergency plan is said to be in operation. Various departments, services and relevant experts are involved in preparation and execution of the off-site emergency plans.
In order to address the paradigm shift envisaged under the DM Act 2005, pro-active risk management framework for chemical disasters is expected to encompass the stages, viz. (a) sensitivity based site assessment (b) hazard analysis and physical risk assessment (c) vulnerability analysis and mapping (d) multi-hazard impact analysis (e) maximum credible accident scenario analysis and consequence assessment (f) disaster risk mitigation (structural & non-structural) (g) emergency planning and preparedness (h) emergency response drills, and (i) operations and evaluations.
Chemical Disaster
Figure VI. Cyclic-framework of preventive risk management for chemical disasters
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