Risk ranking methods

Ranking based on regional and global exposure estimations and qualitative human health and ecological toxicity assessment - European Union Risk Ranking Method. 

Hansen BG, van Haelst AG, van Leeuwen K, and van der Zandt P (1999) Priority setting for existing chemicals European Union risk ranking method. Environmental Toxicology and Chemistry 18 772-779. 

After potential events have been identified, they must be prioritized. Typical risk ranking methods consider the probability or frequency of occurrence and the criticality or potential for injury or environmental impact. You should direct your initial efforts to developing those EOPs that address the greatest risk. 

The amount and type of hazards will determine the performance standard specified in site-specific control plans. This includes the content, detail, and formality of review. The approval of the plans is based on risk and hazard potential. Using the hazard-based approach, levels of risk or methods to rank risk (degree) are standardized. 

The current situation with regard to risk assessment in the use of a wide range of different types of flame retardant is reviewed with respect to EEC council regulation No.793/93. The countries responsible for risk assessment on particular materials are listed and tonnages of materials used are noted. Three methods of prioritisation are used based on quantity used, environmental hazard potential and environmental risk ranking. 6 refs. 

U.S. Department of Health and Human Services (2004), Risk-based method for prioritizing cGMP inspections of pharmaceutical manufacturing sites—A pilot risk ranking model, Food and Drug Administration, Rockville, MD. 

Suter (1990) emphasized that at our current level of knowledge, the detrimental effects of hazardous chemicals on ecosystems cannot be adequately predicted. The current methods can only assess risks in a simplified manner by providing a relative ranking of risk—from chemical-to-chemical or site-to-site. Nonetheless, such relative-risk ranking provides a useful basis for prioritizing environmental hazards, particularly if data are analyzed by qualified risk assessors. 

Decide on an evaluation scheme for each source, stressor, and habitat to allow the calculation of risk to the assessment endpoints. There has to be a scheme for evaluating sources, stressors, and habitats and translating this into a risk calculation. There are many methods, typically using quotients between an observed concentration and a concentration deemed as a threshold above which an unacceptable effect will occur. As previously discussed, this quotient method has drawbacks. Ranking methods are also available as previously discussed. 

Partial and total ranking methods have been widely used to perform data exploration, investigate the inter-relationships of objects and/or variables and set priorities. However it appears a very useful tool even for modelling purposes. Mathematical models have become an extremely useful tool in several scientific fields like environmental monitoring, risk assessment, QSAR and QSPR, i.e. in the search for quantitative relationships between the molecular structure and the biological activity/ chemical properties of chemicals. 

Disclaimer Executive Summary Major Findings General Conclusions Objectives of the Analysis Summary of Findings Method Used Risk Ranking The Team... 

If a quantified method such as LOPA or Fault Tree Analysis is to be used then it will be carried out during Phase III in order to risk rank identified hazards. 

Ranking the risk on the likelihood, exposure, and consequence scale determines the risk score, which could be from extreme (100) to acceptable (0-20). The risk analysis and risk score then enable prioritization of actions by using accepted risk control methods. Once the risks have been analyzed and risk scores determined, it is now possible to do a risk evaluation. 

Use the logical process risk analysis method to determine the ranking for applying funds to each of five plants in a company. Several plants were part of the analysis. The following table lists data for the five plants under current consideration. 

Developing a risk map provides a quick and easy way to identify and focus on critical risks (e.g., those in the red square, high occurrence and high impact). The next step is to rank the risks in the various squares at least in red, orange and yellow squares, so that risk intervention strategies can be developed. We present a simple risk scoring method that uses risk priority numbers (RPNs) to rank the critical risks or at least identify the top 10 or 20 risks that need attention. 

In practice, risk scoring methods are easier to use to get a "quick and dirty" ranking of the risk events. In Sections 7.8-7.13, we discuss mathematical models to quantify the risk factors. 

Semi-quantitative techniques, consisting of index and matrix methods. Examples are Dow Fire and Explosion Index, Mond Index, and Pipeline Index for risk ranking of different facilities of the same type, and the matrix method for risk ranking of potential hazardous events that a given facility or organization can face. 

A number of qualitative hazard identification methods are available to the risk analyst. Some of the more popular ones are discussed here. Further detailed information can be found in CCPS (1992). These methods become more powerful tools if they are coupled with the matrix-based risk-ranking scheme previously described. 

Some companies choose to use the complex PSSR form itself as the method of risk ranking. In this case, they have each PSSR team evaluate every specific item on the checklist for applicability for every trigger event, even when it is an obviously simple modification. In this way, the team qualitatively addresses risk for each item they include in the review. 

Another method of hazard identification is the examination of past accidents and near miss incidents to determine what hazards contributed to the injury or were involved in the event Recurring accidents could indicate specific hazards in the process or the behavior of the people. After risk ranking, near miss incident investigation should receive the same attention as accident investigation and may prove to be more meaningful because it is predictive whereas accident investigation is reactive. 

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