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Causes of Chemical Disasters
Chemical Disaster
Industrial (chemical) hazards are threats to people and life-support systems that arise from the mass production of goods and services. When these threats exceed human coping capabilities or the absorptive capacities of environmental systems they give rise to industrial disasters. Industrial hazards can occur at any stage in the production process, including extraction, processing, manufacture, transportation, storage, use, and disposal. Losses generally involve the release of damaging substances (e.g. chemicals, radioactivity, genetic materials) or damaging levels of energy from industrial facilities or equipment into surrounding environments. This usually occurs in the form of explosions, fires, spills, leaks, or wastes. Releases may occur because of factors that are internal to the industrial system (e.g. engineering flaws) or they may occur because of external factors (e.g. extremes of nature). Releases may be sudden and intensive, as in a power-plant explosion, or gradual and extensive, as in the build-up of ozone-destroying chemicals in the stratosphere or the progressive leakage of improperly disposed toxic wastes.
  • The causes of industrial hazards and disasters are malfunctions, failures, or unanticipated side-effects of technological systems. But this is a misleading oversimplification and many other factors are involved.
  • The calculus of industrial hazard is a blend of industrial systems, people, and environments that also include geological, atmospheric, ecological, psychological and social components. These combine in different ways to create a specific hazard. For example, faulty equipment, operator error, and a south-westerly air flow all helped to shape the events that occurred at Three Mile Island nuclear power station (Sills, Wolf, and Shelanski 1982; Houts, Cleary, and Hu 1988). The Challenger space shuttle disaster involved, among others, a vulnerable fluid seal, cold weather, and an impatient launch team - although the official inquiry blamed only the seal.
  • Explosion in a plant handling or producing toxic substances
  • Accidents in storage facilities handling large and various quantities of chemicals
  • Accidents during the transportation of chemicals from one site to another
  • Misuse of chemicals, resulting in contamination of food stocks or the environment, overdosing of agrochemicals
  • Instantaneous bulk release of pollutants/contaminant
  • Mass release from natural source
  • Improper waste management such as uncontrolled dumping of toxic
  • Chemicals, failure in waste management systems or accidents in wastewater treatment plants
  • Technological system failures
  • Failures of plant safety design or plant components
  • Natural hazards such as fire, earthquakes, landslides
  • Sabotage
  • Mass poisoning (intentional or unintentional)
  • Human error
A number of factors could trigger chemical accidents, some of which are as follows:
  • Process and Safety Control System Failures:
    • Technical errors
    • Human errors
  • Natural calamities: For example, Release of acrylonitrile at Bhuj, during earthquake in 2001, and damage to Phosphoric acid sludge containment during Orissa Supercyclone in 1999.
  • Terrorist attacks/Sabotage
Sources of Chemical Disasters
  • Manufacturing and Formulation Facility (including during Commissioning & Process Operation; Maintenance, Disposal and Waste Management)
  • Material Handling and Storage
    • Bulk Storages: In manufacturing facilities and isolated storages (including tank farms in Ports & Docks
    • Storages of Small Containers: In manufacturing facilities, in isolated warehouses and godowns, and
    • Storage of Fuels (LPG Depots etc.)
  • Pipelines, and
  • Transportation (road-, rail -, air- & waterways)


Impacts
Impacts of chemical disaster may the following and can be further understood in short-term and long-term perspectives:
  • death, injury, physiological health effects and losses
  • damage to environmental resources, like land/soil, land-use, water bodies/resources, air-quality and movements, local-climate, crops/forests and bio-products
  • disruption of environmental services, e.g. water supply, aesthetic and recreation, environmental & public health, sanitation, garbage management
  • damage and losses to structures, buildings, machines/equipment, facilities
  • psychological trauma, stress and lack of well-being
  • insurance losses, and economic losses related to disruption of productivity, wages, remuneration, incentives
  • increase in vulnerability to other hazards including natural and environmental exposures,
  • and law & order instability, community outcries, litigations and public governance disruption
Intensity and damageability of a chemical disaster depends on various factors shown in figure II.
Chemical Disaster


Factors determining severity of a hazardous event
Immediate, short-term and long-term effects of a hazardous chemical incidence depends upon the source of release, geo-physiographic and meteorological conditions, structural settings, and exposures, and relative vulnerability of different factors. A pictorial model of various primary, secondary and following-order impacts is shown at figure III.
Chemical Disaster
Figure III. Environmental sources and various exposures resulting in disaster impacts

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