Situations, acceptable risk levels

In military operations, it is impossible to have zero risk, and indeed, the acceptable risk level in most cases may well be higher than that set for civilian operations. Determining the appropriate level of decontamination for a situation is the result of assessment and decision making based on all of the risks. Setting the appropriate risk levels and decontamination specifications is an area in need of Navy doctrine. Once established, that doctrine could then lead to the development of testing and performance standards to be used for field decontamination, as well as to base and long-term equipment decontamination procedures. The Navy must be able to provide doctrine, guidelines, and expertise in this area. 

For many hazards and the risks that derive from them, knowledge gained by safety practitioners through education and experience will lead to proper conclusions on how to attain an acceptable risk level, without bringing teams of people together for discussion. For the more complex situations, it is vital to seek the counsel of experienced personnel who are close to the work or process. 

Comments follow in support of the logic for the risk reduction actions and the significance of their order of effectiveness. They are excerpted from the chapter The Safety Decision Hierarchy in Innovations in Safety Management In all but the rare situation, application of this hierarchy will result in attaining an acceptable risk level. 

It should be recognized that application of The Safety Decision Hierarchy will, in all but the exceptional situations, attain an acceptable risk level. 

We should recognize that a universally applicable definition of an acceptable risk level cannot be attained, other than in broad general terms, because of the many variables in individual risk situations. 

Requirements to achieve an acceptable risk level in the design process can usually be met without great cost if the decision-making occurs sufficiently upstream. When hazards and risks are not properly dealt with in the design process, and retrofitting to eliminate or control hazards is proposed later, the cost may be so great as to be prohibitive. The result may be a situation in which, subsequently, the risks are judged to be... 

An acceptable risk level must be tolerable in the situation being considered. 

Replacing the term tolerable risk with acceptable risk in BS OHS AS 18001 by an organization as influential as the British Standards Institution is noteworthy. In some parts of the world, because of requirements in contract bid situations, companies are required to show that their safety management systems are certified. BS OHSAS 18001 is often the base of such certification. This modification made by the British Standards Institution indicates that the goal to be achieved is acceptable risk levels. 

Where multiple, diverse hazards exist, the practical approach is to treat each hazard independently, with the intent of achieving acceptable risk levels for all. In the noise and toluene example, the hazards are indeed independent. In complex situations, or when competing solutions to complex systems must be evaluated, the assistance of specialists with knowledge of more sophisticated risk assessment methodologies such as Hazard and Operability Analysis (HAZOP) or Fault Tree Analysis (FTA) may be required. However, for most applications, this author does not recommend that diverse risks be summed through what could be a questionable methodology. 

Some of the MOC examples provided require that risk assessments be made at several stages of the change activity. The intent is to achieve and maintain acceptable risk levels throughout the work process. Thus, risk assessments are to be made as often as needed as changes occur and particularly when unexpected situations arise. In this regard, safety professionals who become skilled in making risk assessments can provide a significant value added consultancy. 

For many risk situations, a combination of the methods shown in the hierarchy of controls is necessary to achieve acceptable risk levels. 

Fire risk assessment is made in order to determine the overall value of decreasing fire hazard in a particular scenario. The level of fire risk that is acceptable for a situation is, normally, a societal, and not a technical, decision. Therefore, fire hazard assessments are generally more common than fire risk assessments. The NFPA Research Foundation has undertaken a project to develop a methodology for fire risk assessment. It has done this by studying four cases in detail upholstered furniture in residential environments, wire and cable in concealed spaces in hotels and motels, floor coverings in offices and wall coverings in restaurants. 

Another factor that helps define the cleaning strategy is recognizing the type of cleaning situation we are faced with relative to what is going to be manufactured next in the equipment. I like to tell people that you ve got to learn to look downstream in cleaning validation in order to determine what you might contaminate and thus determine the element of risk. Some situations are simply more risky than others and we must be able to study and deal with risk. We must be able to accept a certain level of risk because it is always with us and unfortunately cannot be driven down to absolute zero. 

The radiation paradigm also is applied to other situations including cleanup of sites contaminated with uranium or thorium mill tailings, mitigation of indoor radon, remediation of elevated levels of naturally occurring radionuclides other than radon, and responses to radiation accidents. In these applications, the maximum acceptable risk has a value in the range of about 10 1 to 10 3 (Kocher, 1999). 

Acknowledgment that mixtures may cause risks that are not fully covered by single compound evaluations does not automatically imply that mixture assessments should be performed for all potential mixture exposures. This depends on the problem at hand, the specific exposure situation, and the available information. If a regulator must make a decision about the remediation of 1 contaminated soil plot, and it is already known that one of the mixture components exceeds the remediation threshold, and this fact results in a need for remedial action itself, then a mixture assessment is redundant. Mixture assessment for contaminated soils (and other compartments and exposure routes) is useful if the known individual components do not exceed their respective thresholds, but if it is suspected that the overall mixture may still cause unacceptable adverse effects, and in case risk managers have a limited budget for a large number of contaminated sites, that is, when they have to prioritize the most hazardous sites to be remediated first, while other sites should possibly be subject to simple risk reduction measures. The situation is different for mixture emissions. Here, potential mixture effects should always be addressed because the aim was and is to establish an emission level that is lower than a certain (acceptable) effect level. 

C. Emergency Risk. In this category, not more than 5 percent casualties are expected. Nuisance effects may exceed the 5 percent level. The emergency risk dose is only acceptable in rare situations, termed disaster situations. Only the commander can decide when the risk of the disaster situation outweighs the radiation emergency risk. 

It falls to EPA, on behalf of the many involved sectors of the public, to assess the degree of risks posed by the numerous pesticides available, and to determine what level of risk, tempered by benefit, society ought to accept. This level of risk is not necessarily the level which each of us individually would choose, nor is it perfectly adapted to every particular use situation, but is rather a guarantee of a minimum standard of protection combined with the opportunity to enjoy at least certain benefits of the pesticide as well. 

Individually and collectively we are risk acceptors. And risk acceptance is situational Variations in the risk levels that individuals and organizations accept in given situations are exceptionally broad. Nevertheless, in an attempt to promote an understanding of the acceptable risk concept, this chapter does the following ... 

Understandably, the level of acceptable risk in operations where most safety practitioners have influence is much lower than those tolerated in space ventures. For example, a major equipment failure of 1 in 1000 startups—the NASA design standard for Loss of Vehicle (LOV) probability — would be unacceptable in all but the exceptionally unusual situation. 

The concepts inherent in the terms ALARA and ALARP serve as guidelines in determining whether a risk is acceptable, but cannot be used as absolutes in decision-making. It should be understood that in an exceptional situation, even though the risk level attained is as low as reasonably achievable or practicable, a decision will be made that the residual risk is not acceptable and that the operation should not proceed. 

ZlO-2005 tersely states its purpose in Section 1.2 as follows The primary purpose of this standard is to provide a management tool to reduce the risk of occupational injuries, illnesses, and fatalities. This question logically follows. What risk reduction level is to be achieved This chapter Establishes that achieving a zero risk level is unattainable Discusses the great variations in cultural and situational aspects of risk acceptance and Combines the elements of risk (probability and severity) with ALARP (as low as reasonably practicable) to arrive at a definition of acceptable risk, the operational goal. 

Furthermore, safety professionals need to understand that decisions made with respect to risk acceptance or reduction may not always be based on logic. Sometimes, workers have perceptions about risk levels in a given situation that are unrealistically high. Although their perceptions may not be well founded, they have to be addressed in an attempt to diminish their fears. Companies have found that spending a little money to counter unreasonable perceptions of risk may be a good investment if employees are relieved of their fears and production slowdowns or interruptions are avoided. 

We have already established that, in the real world, attaining a zero risk level is not feasible. Nevertheless, the residual risk remaining after risk avoidance, elimination, or reduction measures are taken should be acceptable and tolerable as judged by the decision makers for the work situation being considered. 

Acceptable risk A risk level achieved after protective measures have been applied. It is a risk level that is accepted for a given task (hazardous situation) or hazard. For the purpose of this standard the terms acceptable risk and tolerable risk are considered to be synonymous. 

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