Hazards indirect causes

Interactions refers to any jobs, tasks, or operations carried out by people who could directly or indirectly cause the hazard to be released. Direct interactions with the plant might involve breaking open pipework, opening reactors, etc. Indirect interactions would include remote activation of valves from a control room, or the performance of maintenance on critical plant items. Errors that might occur during these interactions could allow the harm potential to be released. This could occur directly (for example, a worker could be overcome by a chlorine release if an incorrect valve line-up was made) or indirectly (for example, if a pump bearing in a critical cooling circuit was not lubricated, as in the example in Chapter 1). The procedure as described above... 

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. 

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... 

Interfaces can be grouped into intentional and unintentional. Intentional interfaces are planned, designed interfaces, for example, communication links between two subsystems. This is why an intentional action or information type interface can only potentially be an indirect cause of the hazard or the consequence, and hence can only lead to the unintended or uncontrolled release of energy, when it fails to perform as desired. 

Intended interfaces (aimotated by a full black line, for example comms link between the signalling system and onboard computer) Unintended interfaces that are indirect cause of the hazard or the consequence (annotated by black dashed line, for example Electromagnetic Interference) and... 

Unsafe acts (behavior) or unsafe conditions comprise indirect causes of accidents or incidents. These indirect causes can inflict injury, property damage, or equipment failure. They allow the energy or hazardous material to be released. Unsafe acts can lead to unsafe conditions and vice versa. Examples of unsafe acts and unsafe conditions are found in Table 8.2. 

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. 

Now that direct causes have been discussed, let us move one step down from there and discuss indirect causes, or symptoms, that may be considered contributing factors. In most cases, the release of excessive amounts of energy or hazardous materials is caused by unsafe acts or unsafe conditions. Put another way Unsafe acts and unsafe conditions trigger the release of large amounts of energy or hazardous... 

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 exeessive amounts of energy and hazardous materials cause most accidents. With few exceptions, these releases are caused by unsafe acts and unsafe conditions. An unsafe act or an unsafe condition may trigger the release of large amounts of energy or hazardous materials. This may cause the accident. (See Figure 14-3.) Particular attention should be paid to these areas. 

Turning now to indirect effects of neurotoxic pollutants, the status of predators and parasites can be affected by reductions in numbers of the species that they feed upon. Thus, the reduction in numbers of a prey species due to a behavioral effect can, if severe enough, cause a reduction in numbers of a predator. Also, as mentioned earlier, behavioral effects upon a prey species may lead to selective bioaccumulation of persistent neurotoxic pollutants such as DDT and dieldrin by predators thus, a behavioral effect may be hazardous for predator and prey alike ... 

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. 

In addition to the direct absorption as a biological hazard, UV can have additional indirect effects on organisms.26,27 A number of UV photochemical reactions occur in solutions, both within cells and in the external aquatic environment. In the presence of UV, water itself is hydrolyzed, producing hydroxyl ions. Related reactions involving dissolved substances and mediated by UV lead to the formation of peroxides, super oxide, and other radicals. These reactive products are toxic by causing oxidative damage to biological molecules.28-31... 

Size of test system causes significant differences in fate and, therefore, exposure concentrations. However, where exposure regimens are similar, threshold concentrations for similar effects in different types of test systems also are similar, at least when they contain enough representatives of sensitive taxonomic groups. The extrapolation of NOECecosystemvalues from one system to another is possible with lower uncertainty than in hazard estimates of higher concentrations in which both direct and indirect effects and recovery processes are involved. 

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