Hazards direct causes

It is therefore useful to distinguish between active and latent errors or failures. An active human error has an immediate effect in that it either directly causes a hazardous state of the system or is the direct initiator of a chain of events which rapidly leads to the imdesirable state. 

The fact that the main direct cause of death in fires has always been the toxicity of combustion products was already discussed in the National Fire Protection Association (NFPA) Quarterly in 1933 [34]. Smoke contains mainly two types of toxic gases asphyxiants and irritants, but the individual toxic gas associated with the largest fire hazard is carbon monoxide (CO). 

Decomposition reactions are often involved in thermal explosions or runaway reactions, in certain cases as a direct cause, in others indirectly as they are triggered by a desired synthesis reaction that goes out of control. A statistical survey from Great Britain [1, 2] revealed that out of 48 runaway reactions, 32 were directly caused by secondary reactions, whereas in the other cases, secondary reactions were probably involved too, but are not explicitly mentioned (Figure 11.1). Therefore, characterizing secondary decomposition reactions is of primary importance when assessing the thermal hazards of a process. 

Aecording to the World Health Organization (WHO 1985), an occupational disease is a disease for which there is a direct cause-and-effect relationship between hazard and disease (e.g., asbestos-... 

FTA is a top-down or deductive technique. It employs a graphical method to articulate the causes of a top event which, in turn, is directly related to a hazard. Each cause of the top event is analysed further to examine its causes and so on. The resulting structure is represented as a tree, each event being linked by boolean logic operators (and, or, not, etc.). In some cases the top event can be replaced by a lower level event which effectively allows trees to be connected or embedded to model... 

According to the modem accident-causation (G. and B. et al., 2005), from the point of individual behavior-safety control, hazard is embodied unsafe act (behavior) and unsafe condition meanwhile, under certain situation, unsafe act (behavior) can transform and result in unsafe condition. The unsafe act and unsafe condition is the direct cause of accident, deeper analysis comes to the indirect (common) cause, which include three elements inadequate safety knowledge, inadequate safety awareness, and inadequate safety habit. 

Toxicology LDLo (IV, mouse) 9821 mg/kg possible aspiration hazard direct aspiration into the lungs may cause chemical pneumonitis, pulmonary edema, hemorrhaging severe irritant irritating to skin, eyes, respiratory system TSCA listed... 

Software Fault Hazard Analysis Similar in concept and structure to the system hazard analysis (SHA), which is conducted on system hardware, the software fault hazard analysis will analyze and evaluate a computer software program to identify critical areas in the programming that may contribute to or directly cause a hazard risk. Such risks may be due to an undetected hardware failure or incorrect inputs into the operation of the system software. The software FHA will also attempt to uncover any probable errors that can possible develop in the software after system activation. 

Unsafe acts committed by individuals and mechanical or physical hazards are the direct causes of accidents... 

Accidents are usually complex and are the result of multiple causes. A detailed analysis of an accident will normally reveal three cause levels basic, indirect, and direct. At the lowest level, an accident results only when a person or object receives the release of an amount of energy or exposure to hazardous material that cannot be absorbed safely. This energy or hazardous material is the direct cause of the accident. The second causal areas are usually the result of one or more unsafe acts or unsafe conditions, or both. Unsafe acts and conditions are the indirect causes or symptoms. In turn, indirect causes are usually traceable to poor management policies and decisions, or to personal or environmental factors. These are the basic causes. 

Direct causes (unplanned release of energy and/or hazardous material)... 

Most accidents are caused by the unplanned or unwanted release of large amounts of energy, or of hazardous materials. In a breakdown of accident causes, the direct cause is the energy or hazardous material released at the time of the accident. Accident investigators are interested in finding out what the direct cause of an accident is because this information can be used to help prevent other accidents, or to reduce the injuries associated with them. 

If the direct cause is known, then equipment, materials, and facilities can be redesigned to make them safer personal protection can be provided to reduce injuries and workers can be trained to be aware of hazardous situations so that they can protect themselves against them. The remainder of this book is directed toward managing, preventing, and controlling hazards that occur within the nation s industries. 

Direct causes are the basic contributing factors that directly cause the accident to occur. For example, it might be determined that the immediate events or conditions leading up to an accident might be traced to the explosion of a pressurized vessel. The direct cause should be stated in one sentence. Then briefly explain what happened. A direct cause would be the release of energy or hazardous material. (Examples of the release of energy and examples of hazardous material can be found in Chapter 7.) Another example of a direct cause statement would be The electrician made contact between the metal rod and the exposed 220-volt wire. State the cause as simply as humanly possible. 

A detailed description of the direct, indirect, and basic causes of accidents can be found in Chapter 7. Remember, the unplanned or unwanted release of excessive amounts of energy or hazardous materials causes most accidents. With few... 

NOTE 2 When there is a possibiiity that some combination of output states of a subsystem can directly cause a hazardous event then it shouid be necessary to regard the detection of dangerous faults in the subsystem as a safety instrumented function operating in the continuous mode. 

Direct causes (energy sources hazardous materials)... 

It is known that health hazards are caused by inhalation of sub-micron aerosol particles. Drinker and Hatch (1936) stated that vast numbers of particles below 0.25-pm radius are generated by industrial processes and they considered this sub-micron aerosol to be quite dangerous. Particles below 0.1-pm radius are too small for direct microscopic observation. Likewise, the standard light scattering techniques cannot be used. Consequently, the methods in use depend on observation of the particles with the ultramlcroscope or electron microscope. 

Unintentional interfaces are not planned and appear either by a mistake in design, project implementation or as a result of a system failure. An interface that is not intentional is potentially a direct or indirect cause of a hazard or a direct or indirect cause of a consequence. It is only an unintentional interface of energy type that can be a direct cause of a safety consequence (in a sense of uncontrolled or unintended release of energy). An action or information type unintended interface can only be an indirect cause of the hazard or the consequence, and can only lead to the unintended or uncontrolled release of energy. 

Thus, accidents have many causes. Basic (root) causes lead to unsafe acts and unsafe conditions (indirect causes). Indirect causes may result in a release of energy or hazardous material (direct causes). The direct cause may allow for contact, resulting in personal injury or property damage or equipment failure (accident). You can use the accident report form found in Figure 8.2 to identify and analyze these three causes. 

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