Chemical Hazards   Chemical hazards exist to a different extent in all chemical industries. Such hazards may typically be chronic ones (continuous) or of a sporadic or catastrophic nature. Chemical hazards in the chemical industry are usually associated with a loss of containment i.e. a release of a chemical to the atmosphere through a specified route. UNCONTROLLED releases of importance are essentially of either LONG TERM UNCONTROLLED (say due to a jet release from a pressurised pipeline over a period) or SHORT TERM UNCONTROLLED (say due to an instantaneous equipment rupture) types, the consequence of which is dependent upon the plant design and operational features. In addition, there exist SHORT TERM CONTROLLED and LONG TERM CONTROLLED releases, the latter being one of the concerns for long term or chronic health and environmental effects. Continuous releases of a chemical to the atmosphere can be associated with either: A design defect/ maximum achievable value. This could characterise a release from say a stack, where there may not be further margin to achieve economic or technical feasibility. The failure of an equipment or process/ operation shortcoming. Predicting possible equipment or system failures is very important in hazard analysis - a brief note on Failures is given below. It is important to predict failures (WHERE AND WHEN) systematically- the outcome of this prediction would help in the hazard reduction programs.