Hazard identification generally

The Center for Chemical Process Safety s projects fall into a number of general topic areas that comprise a comprehensive program. These topic areas include identification of hazards and analysis of risks, prevention and mitigation of the hazards identified, and better definition of areas affected by a release of hazardous materials. This book is the latest in the series dealing with hazard identification and risk analysis. 

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... 

The terminology used varies considerably. Hazard identification and risk assessment are sometimes combined into a general category called hazard evaluation. Risk assessment is sometimes called hazard analysis. A risk assessment procedure that determines probabilities is frequently called probabilistic risk assessment (PRA), whereas a procedure that determines probability and consequences is called quantitative risk analysis (QRA). 

Thus, for hazard identification, only the measurement of one or two temperatures is necessary. Actually, for equipment without a heating or cooling system, evaluation of the term (d2T/dt2) greater than zero is sufficient. The method is independent of detailed process knowledge and, generally, of human judgment. 

In general, hazard identification criterion represents the deviation of one or more measured variables from specified values. This is the basis upon which a significant percentage of risk analyses are done. For a chemical process, a number of measurable variables, physical properties, and states or positions of various parts of the overall equipment, e.g., pumps, valves, and motors, can be specified for every time or phase of the process. Certain deviations from the "standard" recipe or settings can then be defined in advance as hazardous, and thus can be used for initiation of an alarm at the early stage of a runaway or upset condition. 

Logic Model Methods The following tools are most commonly used in quantitative risk analysis, but can also be useful qualitatively to understand the combinations of events which can cause an accident. The logic models can also be useful in understanding how protective systems impact various potential accident scenarios. These methods will be thoroughly discussed in the Risk Analysis subsection. Also, hazard identification and evaluation tools discussed in this section are valuable precursors to a quantitative risk analysis (QRA). Generally a QRA quantifies the risk of hazard scenarios which have been identified by using tools such as those discussed above. 

In general, data from studies in humans are preferred to animal data for purposes of hazard identification and dose-response assessment. 

Thus, the hazard identification, in addition to an identification of the inherent toxicological properties (type of effects), also involves an evaluation of the nature of the observed effects, i.e. (1) whether an observed effect constitutes an adverse effect and thus results in an impairment of body function(s), and (2) whether an effect is a direct toxic effect exerted by the chemical (biologically relevant) or is due to normal unspecific reactions toward changes in the environment (homeostasis). Examples of effects, which generally are not considered as being adverse, include ... 

Chemical hazard identification. In contrast to radiation, most chemicals are thought not to be hazardous to human health at a sufficiently low dose. In the United States, the process of determining whether a chemical is hazardous relies upon principles established by EPA. These principles are used extensively, but not universally, in other countries. This Section describes the general principles used by EPA to identify hazardous chemicals. Hazard identification is related to the process of dose-response assessment for hazardous chemicals discussed in Section 3.2.1. 

Hazard Identification. The first step is to determine whether a substance is mutagenic. For this purpose, inexpensive and sensitive short-term tests have been developed and are extensively used, nils report discusses the general features of these tests and proposes a specific mutagenicity screening program to detect potential mammalian mutagens. 

Hirschler, M.M., General principles of fire hazard and the role of smoke toxicity, in Fire and Polymers Hazards Identification and Prevention, Ed. G.L. Nelson, ACS Symposium Series 425, American Chemical Society, Washington, DC, Chapter 28, pp. 462-478, 1990. 

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.

Several assays have been developed for assessing genetic alterations in germ cells. The information developed can be used for hazard identification in the cancer risk assessment process or, more appropriately, in the development of a genetic risk assessment. The decision of when to conduct a germ cell assay is an important one because the assays are generally expensive and time-consuming. An exception is the use of Drosophila in assays that can serve as a substitute for mammalian assays. 

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