Step 1 - Hazard Identification

Various methods may be used individually or in a combination to carry out Step 1 of the FSA approach. Such typical methods include Preliminary Hazard Analysis (PHA), Fault Tree Analysis (FTA), Event Tree Analysis (ETA), Cause-Consequence Analysis (CCA), Failure Mode, Effects and Criticality Analysis (P MECA), HAZard and OPerability analysis (HA2X)P), Boolean Representation Method (BRM) and Simulation analysis (Henley and Kumamoto (1996), Smith (1992), Villemeur (1992), Wang (1994)). The use of these methods as safety analysis techniques has been reviewed in Chapter 3. 

In the hazard identification phase, the combined experience and insight of engineers is required to systematically identify all potential failure events at each required indenture level with a view to assessing their influences on system safety and performance. This is achieved using brainstorming techniques. The hazard identification phase can be further broken down into several steps as follows  

Define the bounds of study, generic vessel and generic stakeholder for the 

Problem identification - The problem boundaries of a formal safety assessment study can be developed in the following manner  

In addition, the following factors specifically related to the vessel are defined  

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Figure 5.1 Risk assessment is traditionally organized in a series of consecutive steps—1) hazard identification, 2) exposure assessment, 3) effect assessment, and 4) risk characterization—and generally embedded in a wider framework involving research, problem formulation, risk management, and action.

The project s risk assessment effort followed ERA methods and established agency policy as outlined by the National Academy of Sciences (NAS, 1983) and established in final risk assessment guidelines (ERA, 1986). It involved four steps (1) hazard identification, (2) determination of dose-response relations, (3) evaluation of human exposme and, finally, (4) characterization of risks. 

Step 1 hazard identification. This step involves considerable data collection and input by plant personnel. This ensures that an accurate picture of current operations, incidents, and hence potential risks is achieved. See Fig. E-58. 

The health risk evaluation process consists of four steps hazard identification, dose-response assessment or hazard assessment, exposure assessment, mid risk cliaracterization. 

In this chapter the risk assessment is briefly introduced. Risk assessment is divided into four steps hazard identification, hazard characterization, exposure assessment, and risk characterization. This chapter also highlights five risk and life cycle impact assessment models (EUSES, USEtox, GLOBOX, SADA, and MAFRAM) that allows for assessment of risks to human health and the environment. In addition other 12 models were appointed. Finally, in the last section of this chapter, there is a compilation of useful data sources for risk assessment. The data source selection is essential to obtain high quality data. This source selection is divided into two parts. First, six frequently used databases for physicochemical... 

For the two aforementioned steps, hazard identification and hazard characterization, data adequacy is of high importance. The data adequacy is defined by the reliability and the relevance of the data for human risk assessment [3],... 

Risk Assessment The scientific process of evaluating the toxic properties of a chemical and the conditions of human exposure to it, in order to ascertain the likelihood that exposed humans will be adversely affected, and to characterize the nature of the effects they may experience. It may contain some or all of the following four steps hazard identification, dose-response assessment, exposure assessment, and risk characterization. 

Within the framework depicted in Figure 7.1, the content of risk assessment proposed by the committee is shown as comprising four analytic steps hazard identification, dose-response assessment, human exposure assessment, and a final, integrating step called risk characterization. These four terms and the activities they describe have come to be widely accepted within the risk assessment community, on... 

The Risk Assessment process includes four steps hazard identification, hazard characterization (related term dose-response assessment), exposure assessment, and risk characterization. It is the first component in a risk analysis process. 

As mentioned above, the hazard assessment process comprises two steps hazard identification and hazard characterization. 

Health risk assessment is defined as tlie process or procedure used to estimate tlie likelihood that humans or ecological systems will be adversely affected by a chemical or physical agent under a specific set of conditions. Tlie health risk evaluation process consists of four steps hazard identification, dose-response assessment or liazard assessment, exposure assessment, and risk characterization. 

Human health risk assessments with chemicals and other agents (biological, physical) typically follow a paradigm that involves four steps - hazard identification, dose-response assessment, exposure assessment, and risk characterization. The process was recommended by the US National Research Council in the 1980s, and is usually applied to a single agent and exposures associated with one or more routes (oral, dermal, inhalation). This has been more recently referred to as aggregate exposure and risk assessment. 

The risk assessment comprises of three steps hazard identification, consequence analysis, quantitative analysis and frequency assessment (Fig. 7). 

Risk assessment is usually divided into four steps hazard identification, hazard characterization, exposure assessment, and, finally, risk characterization [1]. In hazard identification, agents capable of exerting negative health effects are identified. Often, the first indications of toxic potential of a compound or mixture are derived from epidemiological studies. The advantage of epidemiological studies is that extrapolation from experimental animal studies is unnecessary. On the other hand, indications from epidemiological studies show that unwanted exposure has already taken place. For marine biotoxins in bivalve mollusks, all known syndromes have been detected as a result of... 

A risk assessment is performed in four steps hazard identification, analysis of exposure, analysis of effect, and risk characterization. The same general process is used to assess risk from many different types of threats, not just toxic chanicals. Risk assessments are performed for individual chemicals. When exposure is to a mixture of chemicals, risk assessments are performed for each individual chemical in the mixture. Generally, the health risks from individual chemicals are added together to estimate the total health risk from the mixture of chemicals. In other words, health risks are generally considered to be additive. If there is evidence that two chemicals either enhance or interfere with each other s toxicity, then that information is factored into the risk assessment, usually in the risk characterization step. 

The remaining step in the hazard identification and risk assessment procedure shown in Figure 1 is to decide on risk acceptance. For this step, few resources are available and analysts are left basically by themselves. Some companies have formal risk acceptance criteria. Most companies, however, use the results on a relative basis. That is, the results are compared to another process or processes where hazards and risks are weU-characterized. 

The hazard identification step of the QRA typically requires the greatest involvement of plant personnel. For an existing process, only plant personnel know the status of process equipment and the current operating and maintenance practices. Excluding those personnel from the hazard identification step increases the chance of overlooking important potential hazards. For accurate results, the QRA team must have access to this information. 

The cost of performing the hazard identification step depends on the size of the problem and the specific techniques used. Techniques such as brainstorming, what-if analyses, or checklists tend to be less expensive than other more structured methods. Hazard and operability (HAZOP) analyses and failure modes and effects analyses (FMEAs) involve many people and tend to be more expensive. But, you can have greater confidence in the exhaustiveness of HAZOP and FMEA techniques—their rigorous approach helps ensure completeness. However, no technique can guarantee that all hazards or potential accidents have been identified. Figure 8 is an example of the hazards identified in a HAZOP study. Hazard identification can require from 10% to 25% of the total effort in a QRA study. 

The frequency analysis step involves estimating the likelihood of occurrence of each of the undesired situations defined in the hazard identification step. Sometimes you can do this through direct comparison with experience or extrapolation from historical accident data. While this method may be of great assistance in determining accident frequencies, most accidents analyzed by QRA are so rare that the frequencies must be synthesized using frequency estimation methods and models. 

The hazard identification step is perhaps the most important, because any hazard not identified will not be considered in the decision process. For example, the impact of chlorofluorocarbons on atmospheric ozone was unknown for much of the period of their use, and this potential hazard was not considered until recent years. 

Hazard identification, step one, means identification of new chemicals or other factors that may cause harmful health effects. Previously, novel hazards were usually observed in case studies or after accidents or other excessive exposures, usually in occupational environments. Today, thorough toxicity studies are required on all pesticides, food additives, and drugs. New chemicals also have to be studied for their potential toxic effects. Thus, earlier hazards were in most cases identified after they had caused harmful effects in humans. Today, most chemical products have been evaluated for their toxicity with experimental animals. Therefore, hazard identification has become a preventive procedure based on safety studies conducted before a chemical compound or product reaches the market, and before individuals are exposed to it. ... 

Hazard identification is the first step in process risk management. In order for this procedure to be adequately utilized, the hazard identification team must... 

In this study detailed fault trees with probability and failure rate calculations were generated for the events (1) Fatality due to Explosion, Fire, Toxic Release or Asphyxiation at the Process Development Unit (PDU) Coal Gasification Process and (2) Loss of Availability of the PDU. The fault trees for the PDU were synthesized by Design Sciences, Inc., and then subjected to multiple reviews by Combustion Engineering. The steps involved in hazard identification and evaluation, fault tree generation, probability assessment, and design alteration are presented in the main body of this report. The fault trees, cut sets, failure rate data and unavailability calculations are included as attachments to this report. Although both safety and reliability trees have been constructed for the PDU, the verification and analysis of these trees were not completed as a result of the curtailment of the demonstration plant project. Certain items not completed for the PDU risk and reliability assessment are listed. 

Most human or environmental healtli hazards can be evaluated by dissecting tlie analysis into four parts liazard identification, dose-response assessment or hazard assessment, exposure assessment, and risk characterization. For some perceived healtli liazards, tlie risk assessment might stop with tlie first step, liazard identification, if no adverse effect is identified or if an agency elects to take regulatory action witliout furtlier analysis. Regarding liazard identification, a hazard is defined as a toxic agent or a set of conditions that luis the potential to cause adverse effects to hmnan health or tlie environment. Healtli hazard identification involves an evaluation of various forms of information in order to identify the different liaz.ards. Dose-response or toxicity assessment is required in an overall assessment responses/cffects can vary widely since all chemicals and contaminants vary in their capacity to cause adverse effects. This step frequently requires that assumptions be made to relate... 

Generally, the main pathways of exposure considered in tliis step are atmospheric surface and groundwater transport, ingestion of toxic materials that luu c passed tlu-ough the aquatic and tcncstrial food chain, and dermal absorption. Once an exposure assessment determines the quantity of a chemical with which human populations nniy come in contact, the information can be combined with toxicity data (from the hazard identification process) to estimate potential health risks." The primary purpose of an exposure assessment is to... 

What arc some of the important complications in the "hazard identification step of the health risk assessment process ... 

The degree of confidence in the final estimation of risk depends on variability, uncertainty, and assumptions identified in all previous steps. The nature of the information available for risk characterization and the associated uncertainties can vary widely, and no single approach is suitable for all hazard and exposure scenarios. In cases in which risk characterization is concluded before human exposure occurs, for example, with food additives that require prior approval, both hazard identification and hazard characterization are largely dependent on animal experiments. And exposure is a theoretical estimate based on predicted uses or residue levels. In contrast, in cases of prior human exposure, hazard identification and hazard characterization may be based on studies in humans and exposure assessment can be based on real-life, actual intake measurements. The influence of estimates and assumptions can be evaluated by using sensitivity and uncertainty analyses. - Risk assessment procedures differ in a range of possible options from relatively unso-... 

Due to this, it is necessary to assess the risk to human health and the environment due to the exposure to these chemical additives. In this chapter the impacts that a substance can cause to a certain receptor (humans and the environment) and the harms to the receptor at different exposure levels are identified in hazard identification and hazard characterization steps, respectively. Exposure assessment takes into account the amount, frequency, and duration of the exposure to the substance. Finally, risk characterization evaluates the increased risk caused by such exposure to the exposed population. 

During the identification step, the potential hazards and methods of contact are identified and recorded. As illustrated in Table 3-5, the potential hazards are numerous, especially because the listed hazards can also act in combination. This fist of potential hazards together with the required data for hazard identification (see Table 3-6) is commonly used during the identification step of industrial hygiene projects. 

Hazard identification can be performed independent of risk assessment. However, the best result is obtained if they are done together. One outcome is that hazards of low probability and minimal consequences are identified and addressed with the result that the process is gold-plated. This means that potentially unnecessary and expensive safety equipment and procedures are implemented. For instance, flying aircraft and tornadoes are hazards to a chemical plant. What are the chances of their occurrence, and what should be done about them For most facilities the probability of these hazards is small No steps are required for prevention. Likewise, hazards with reasonable probability but minimal consequences are sometimes also neglected. 

An important part of the hazard identification procedure shown in Figure 10-1 is the risk acceptance step. Each organization using these procedures must have suitable criteria. 

When applied to a particular site and/or project, RA procedures include several generic steps such as hazard identification, hazard assessment, risk estimation and risk evaluation. 

Hazard identification is akin to the qualitative prediction of impacts in EIA and is largely accomplished when the EIA is performed independently of, or prior to, an ERA. The potentially significant risks are often identified because of experience elsewhere with similar materials, processes, ecosystems, and conditions. This step is immediately useful to management and helps to sharpen the question posed in the... 

Leggett, D.J. 2002. "Chemical Reaction Hazard Identification and Evaluation Taking the First Steps." AIChE Loss Prevention Symposium, New Orleans. March. 

Scientists skilled in epidemiology, toxicology, and related disciplines collect and evaluate all of the scientific literature containing information regarding the types of toxic effect the chemical under review has been shown to produce. Toxic effects include one or more of the many manifestations of toxicity described earlier in this book. The list of adverse health effects produced by the chemical are said to constitute its toxic hazards, and the critical review and evaluation leading to the list is the hazard identification step. A discussion of the extent to which causal associations with human disease or toxic harm have been established is an important aspect of this step. 

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