Risk assessment safety concept

Keywords Analytical Hierarchy Processing, artificial neural networks, cost, decision making, decision support systems, marine safety assessment, multiple criteria decision analysis, risk assessment, Taguchi concept. 

The concept of risk assessment requires a profound understanding of food dynamics and technological conditions that may impact the risk levels of certain hazardous compounds. It requires that scientific information and data are collected to underpin conclusions about risk levels. Risk assessment can be used to scientifically underpin the selection of hazards that must be covered by a quality or safety assurance system (e.g., HACCP) that will improve the reliability of the system. 

According to Kharbanda and Stallworthy (1988) safety is a concept covering hazard identification, risk assessment and accident prevention. Safety should always come first and remain so despite of costs. Good design and forethought can often bring increased safety at less cost. 

In 1993, the Center for Chemical Process Safety (CCPS) published Guidelines for Safe Automation of Chemical Processes (referred to henceforth as Safe Automation). Safe Automation provides guidelines for the application of automation systems used to control and shut down chemical and petrochemical processes. The popularity of one of the hazard and risk analysis methods presented in Safe Automation led to the publication of the 2001 Concept Series book from CCPS, Layer of Protection Analysis A Simplified Risk Assessment Approach. This method builds upon traditional process hazards analysis techniques. It uses a semiquantitative approach to define the required performance for each identified protective system. 

The methodology outlined in this chapter follows that in Cuidelines for Chemical Process Quantitative Risk Analysis (CCPS, 2000). NFPA 550 Cu/de to the Fire Safety Concept Tree provides another example of fire risk assessment. There are three keys to a successful fire risk assessment ... 

As a tool to make mutual acceptance of risk assessments possible, OECD has developed the concept of Good Laboratory Practice (GLP). The OECD Principles of GLP are an integral part of the 1981 OECD council decision on the Mutual Assessment of Data (MAD) in the Assessment of Chemicals (revised 1997, Section 2.2.2). MAD also harmonizes procedures of GLP compliance monitoring, ensuring that preclinical safety studies are carried out according to the principles of GLP and that countries can have conftdence in the quahty and rigor of safety tests. 

A critical issue in the development stage in step 1 is that the concept of the product developed should satisfy functional and safety aspects to achieve the expected treatment effectively. When the concept is developed, it must be reviewed based upon risk assessment. One of important issues in step 1 is to establish whether the device will be sterile or not. 

One of the most critical steps in establishing the appropriate role and settings of the individual safety systems will be the risk assessment analysis, the process in which engineers consider and analyse all possible conditions in order to select the most appropriate safety concept, which ensures safe operation under all possible circumstances and scenarios (see Section 13.4). 

Last, but not least, safety is considered in terms of the analysis of the risks associated with potential hazards identified by detailed consideration of the proposed process flowsheet. Safety is the number one concern for chemical engineers and the reader should not confuse the fact that it is the focus of the final chapter in this book with its order of importance. However, in order to carry out a hazard study and risk assessment, one must understand the concepts on which a process flowsheet is developed, and these are covered in the preceding chapters. The procedure describe in Chapter 10 is recognised as best practice in the process industry sector. 

IPCS (1993) Biomarkers and risk assessment concepts and principles. Geneva, World Health Organization, International Programme on Chemical Safety (Environmental Health Criteria 155). 

Risk assessment iinoKes the integration of the information and analysis associated with the above four steps to provide a complete characterization of the nature and magnitude of risk and the degree of confidence associated with tliis characterization. A critical component of the assessment is a full elucidation of the uncertainties associated witli each of die major steps. Under this broad concept of risk assessment are encompassed all of the essential problems of toxicology. Risk assessment takes into account all of the available dose-response data. It should treat uncertainty not by the application of arbitrary safety factors, but by stating them in quantitatively and qualitatively explicit tenns, so tluit they tire not hidden from decision makers. Risk assessment defined in tliis broad way, forces an assessor to confront all the scientific uncertainties and to set fortli in e.xplicit terms tlie means used in specific cases to deal with these uncertainties. An e. panded presentation on each of the four hcaltli risk assessment steps is provided telow. 

Fishbein L. Critical elements in priority selections and ranking systems for risk assessment of chemicals. In Mehlman MA, editor, Advances in modem environmental toxicology Safety evaluation Toxicology, methods, concepts and risk assessment, Vol. X. Princeton, NJ Princeton Scientific Publications, 1987. p. 1-50. 

The threshold of toxicological concern (TTC) concept has been developed to provide criteria for risk assessment decision-making in the absence of detailed information on chemicals. The approach involves estimating a tolerable human exposure value for all chemicals below which there is a very low probability of an appreciable risk to human health (Kroes et al. 2004, 2005), based on their chemical structures, compared to an extensive toxicity database. As utilized by U.S. FDA in their Threshold of Regulation procedure, structural alerts for high-potency carcinogenicity are included, to increase the assurance of safety. 

This book leads the reader from the basic concepts in information retrieval, through hazard and risk assessment and risk management, to the all-important topic of chemical safety and legal aspects. 

This chapter presents the basic concepts and definition of risk (Section 3.1), a protocol for conducting transportation risk assessments (Section 3.2), and a prioritization process for identifying important issues and transportation scenarios requiring a more detailed risk analysis (Section 3.3). Due to the differences in safety and security definitions and risk assessment methodologies, the focus of Chapters 3, 4, and 5 is limited to transportation safety. Security concepts, definition, and assessment methods are presented separately in Chapter 6, with this chapter providing a high-level comparison of safety and security. 

For nongenotoxic chemicals, risk assessment is based on the concept of threshold doses, below which no adverse effect results from exposure. From human or experimental animal data, one tries to establish the no observable adverse effect level (NOAEL) and the lowest observed adverse effect level (LOAEL). In order to establish safe levels of exposure to potentially toxic agents, the NOAEL is divided by a safety factor (often named uncertainty factor). When the risk assessment is based on data from experimental animals, a default safety factor of 100 is usually applied. The safety factor constitutes a factor of 10 for potential differences in susceptibility between animals and man, and another factor of 10 for interindividual differences among humans. The factors are combinations of differences in toxicokinetics and toxicodynamics, both in animals and man. If true factors are known, the size of the safety factor may be changed accordingly. When risk assessment is based on human data, a safety factor of 10 is applied in most cases, for instance, for food additives. However, for natural toxins in food, smaller factors are usually applied. This is a risk management decision, often based on information on the absence of adverse health effects at intake levels close to the estimated LOAELs. 

The new concepts, techniques and approaches that are creating a ferment in Toxicology, taken together with the impetus fuelled by accelerating advances in the basic sciences, bid fair to revolutionize the practice of risk assessment. Whether this very real promise will be translated into concrete achievements in terms of greater safety depends on the freedom and encouragement afforded to the toxicologist to participate in and advance the revolution. 

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