Step 1 Hazard Risk Assessment

Safety lifecycle phase or activity Objectives Requirements Clause or Subclause of ISA-84.01-2004 Inputs Outputs 

The hazard identification process started during the business decision anaiysis (ciauses 2.1 2.2). it is one of the most important functions of the PHA team, and is ongoing untii the process is turned over to plant operations and becomes subject to operational safety review and audit programs. 

The first step in any process development planning is to identify the broad parameters of the production process, to define safety and environmental hazards (or hazardous events), and to seek opportunities for making the process inherently safer. To do this, information is required about the physical and hazardous properties of all the feedstock, intermediates, products and wastes involved in possible alternative processes. For this example, where a specific polymer is being made from its monomer, there is little choice about the basic reactant. The available alternative processes vary the polymerization medium-solution, suspension or emulsion. The significant properties of VCM are summarized in Table 2. 

NOTE — This is an exampie oniy for educational purposes. Contact vendors for the latest VCM material safety data sheet. 

However, the reaction conditions and the initiator (plus any additives) need to be carefully chosen to assure that the reaction rate can be safely controlled to prevent runaway reactions, while producing adequate quality and yield. The selected technology involves polymerization in water, but does require small quantities of a relatively dangerous liquid initiator. The hazards associated with the initiator also need careful attention, but are not included in this simplified example. 

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Hazard characterization is the second stage in the process of hazard assessment, and the second step in risk assessment. 

The first step in risk assessment is to gather health-related information associated with an exposure. Ideally, hazard identification starts before there is significant use of the agent. The structure of the compound is compared with that of compounds with known toxicity profiles. Cell-based studies are often performed to screen for toxicity. Finally, animal bioassays and human studies are performed to characterize and develop a toxicity profile. Multiple health-related endpoints are evaluated to determine if the compound is associated with adverse effects. Advantages of animal studies include experimental control and accurate knowledge of the dose. 

Risk assessment applies to all activities in the laboratory, including lifting heavy equipment and use of furnaces, for example, whether or not any hazardous substances are involved. The five basic steps in risk assessment are 1. Look for the hazards. 

Assessment of the Risk to People. The first step in risk assessment defines the physical, chemical and pharmacological nature of the hazard. Considerations to be made may include ... 

Hazard is distinguished from risk a substance that is toxic to humans is indeed a hazard but is not a risk as long as no human exposure occurs. If a hazard has been identified, the next steps of risk assessment become important. 

The first step in risk assessment in any project is to identify the potential hazards involved. This is done using Hazard Studies, which have been developed as a means of identifying and managing hazards in the design, building and early stages of operation of chemical plant. They are adaptable and may address both process and non-process hazards. 

The product of the exposure assessment process should provide the scientific basis for risk management and communication, which are often initiated by identifying possible hazards. As a measurement, the result is complete only when accompanied by a quantitative statement of its uncertainty (Taylor Kuyatt, 1994), which is required in order to decide whether the result is adequate for its intended purpose and to ascertain whether it is consistent with other similar results. In 2002, the European Commission s Health and Consumer Protection Directorate-General published a scheme in a report on animal health that highlights the role played by exposure assessment in risk assessment and emphasizes the need for risk communication in all steps of risk assessment (EC, 2002). 

ASSESSMENT OF RISKS TO HUMANS EXPOSED TO PESTICIDES 2 The Four Steps in Risk Assessment 2 Hazard Identification 2 Dose-Response Assessment 3 Margin of Safety Approach 3 Quantitative Risk Assessment 3 Exposure Assessment 4 Risk Characterization 4 RISK MANAGEMENT 5 ADVANCES IN DATA INTERPRETATION 5 Probabilistic Approaches 5 Recognition of the Tier Approach 5 Aggregate Exposure 6 Cumulative Exposure 6 Impact of New Scientific Advances 7 Post-Registration Monitoring 7 HARMONIZATION OF REGULATORY APPROACHES SUMMARY 9... 

THE FOUR STEPS IN RISK ASSESSMENT Hazard Identification... 

Briefly discuss why event/liaz.ard identification is a critical step in any hazard risk assessment process,... 

Most risk assessments use data based on assumptions and extrapolations. These generate uncertainties due to the lack of knowledge or data. A degree of caution is used by risk assessors in assigning absolute numbers to risk values and hazard indices because a significant degree of uncertainty is inherent in each of the four steps of risk assessment, which is then compounded into the final risk value. 

The discerning reader may have noticed that the contents of the chapters of this book match the steps of risk assessment. Hazard evaluation concerns the type of material presented in Chapters 3 through 8. Dose—response was treated in 9, and human exposure evaluation was briefly reviewed in Chapters 1 and 2. 

The first type concerns the hazards of these chemicals their flammability, their explosivity, their radioactivity, and their toxicity. In the present context we are interested in the toxic properties of these chemicals. So, it would be necessary, under what is called the hazard evaluation step of risk assessment, to assemble all the available epidemiology and experimental toxicity data (the latter to include animal toxicity studies, ADME data, and studies of mechanisms of toxic action). The assembled data would then be critically evaluated to answer the question what forms of toxicity can be caused by the chemical of interest, and how certain can we be that human beings will be vulnerable to these toxic effects (under some conditions) ... 

The three steps of risk assessment are hazard identification, risk analysis, and risk evaluation. Only once these processes have been completed can a total risk profile be compiled. 

The next step after risk assessment of alarm system is to determine priorities for each signal defined taking into account the severity of consequences for personnel, equipment and plant in case of no reaction of the operator for hazardous event occurred and time available for reaction to prevent accident. 

The next step involves risk assessment. Here one looks at the frequency or likelihood and severity of events involving the identified hazards. This includes event patterns, such as intermittent or continuous. 

Hazard identification is the crucial first step of risk assessment. Only significant hazards, which could result in serious harm to people, should be identified. Trivial hazards should be ignored. 

It is very useful to keep a written record of the risk assessment even if there are less than five employees in the organization. For an assessment to be suitable and sufficient only the significant hazards and conclusions need be recorded. The record should also include details of the groups of people affected by the hazards and the existing control measures and their effectiveness. The conclusions should identify any new controls required and a review date. The HSE booklet Five steps to risk assessment provides a very useful guide and examples of the detail required for most risk assessments. 

A more sophisticated approach will often be required where hazards and risks are changing frequently, as in the construction industry, and also where clients, work partners and other external organisations seek evidence of more detailed analysis than Five Steps to Risk Assessment is likely to provide. There is no shortage of more complicated commercial systems, and these are often computer-based so as to enable quick updating in changing conditions and rapid review. 

There are a large number of standard methods suitable for each stage in the hazard analysis and risk assessment procedure. The selection of the proper method depends on several factors. Some of these are the type of process, the stage in the lifetime of the process, the experience and capabiUties of the participants, and the step in the procedure that is being examined. Information regarding the selection of the proper procedure is available in an excellent and comprehensive reference (1). 

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. 

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... 

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

Risk characterization is the last step in the risk assessment procedure. It is the quantitative or semi-quantitative estimation, including uncertainties, of frequency and severity of known or potential adverse health effects in a given population based on the previous steps. Risk characterization is the step that integrates information on hazard and exposure to estimate the magnitude of a risk. Comparison of the numerical output of hazard characterization with the estimated intake will give an indication of whether the estimated intake is a health concern. ... 

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-... 

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