Forms of risk assessment

Apart from the duty under the Management of Health and Safety at Work Regulations to undertake a health and safety risk assessment of any person (employees, contractors or members of the public) who may be affected by the activities of the organization, the following regulations require a specific risk assessment to be made  

A quantitative risk assessment attempts to measure the risk by relating the probability of the risk occurring to the possible severity of the outcome and then giving the risk a numerical value. This method of risk assessment is used in situations where a malfunction could be very serious (e.g. aircraft design and maintenance or the petrochemical industry). 

The more common form of risk assessment is the qualitative assessment which is based purely on personal judgement and is normally defined as high, medium or low. Qualitative risk assessments are usually satisfactory since the definition (high, medium or low) is normally used to determine the time frame in which further action is to be taken. 

The term generic risk assessment is sometimes used and describes a risk assessment which covers similar activities or work equipment in different departments, sites or companies. Such assessments are often produced by specialist bodies, such as trade associations. If used, they must be appropriate to the particular job and they will need to be extended to cover additional hazards or risks. 

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This form of risk assessment is based on the concept of defining an exposure level, the derived standard, expressed usually on a temporal basis (e.g., daily, weekly), which is considered to offer sufficient reassurance of protection of human health, and then comparing this with an estimated level of exposure. If the estimated exposure is higher than the standard, then further regulatory intervention may be needed. Please see Section 5.12 for a discussion of the health implications of exceeding the tolerable intake. 

Extrapolations are integral to all forms of risk assessment and to all levels of refinement in the risk assessment process. Short of testing all combinations and permutations in physical experiments, it is not possible to conduct risk assessments and make risk management decisions without using extrapolations to one degree or another. 

Up to this point we have been exclusively concerned with identifying hazards. We have not been concerned with asking whether the hazards present any significant risk, or prioritising them in any way (recall that the risk is a combination of the severity of the hazard and the probability of its occurrence). For much of the time it will be intuitively obvious whether measures ought to be taken to eliminate or deal with an identified hazard. However, on occasion the decision might not be clear-cut and some form of risk assessment will be needed. 

Through some form of risks assessment it is possible to obtain a measure of the absolute or relative magnitude of the risks posed. However, there is no standard form of risks assessment methodology or a generally accepted standard for what is an acceptable risk, not are all or most of the data required for risk assessment likely to be available. Moreover, neither is it obvious, or generally agreed upon, as to how to compare fundamentally different types of risk posed by hazardous waste, such as acute versus chronic health effects and environmental damage versus health effects. 

The railway industry is overburdened with paperwork, such that it is to be doubted that many individuals can have a proper grasp of all the documents for which they bear nominal responsibility. The stock answer to any problem which is identified is to produce yet more paperwork in the form of risk assessments. Group Standards and the like. .. the... 

This author suggests that particular attention be given to measuring effectiveness and economic value job safety analysis, which is a form of risk assessment and ergonomics, which also requires that risk assessments be made. 

This example shows how the SIL rating depends on the estimated risk frequency. This places great responsibility on the hazard analysis study, but this will always be a critical task in any form of risk assessment. 

The hazards identification procedures presented in chapter 10 include some aspects of risk assessment. The Dow F EI includes a calculation of the maximum probable property damage (MPPD) and the maximum probable days outage (MPDO). This is a form of consequences analysis. However, these numbers are obtained by some rather simple calculations involving published correlations. Hazard and operability (HAZOP) studies provide information on how a particular accident occurs. This is a form of incident identification. No probabilities or numbers are used with the typical HAZOP study, although the experience of the review committee is used to decide on an appropriate course of action. 

The systematic evaluation of substance properties and predictable or actual exposure patterns over the entire life-time of a substance within the scope of risk assessment is as yet a relatively recent instrument, for which harmonised scientific rales were created in the EU for the first time in 1997 in the form of the Technical Guidance Documents (TGD). An essential element in this range of instruments is how to deal with shortcomings in knowledge. Wherever information is missing, standardised worst-case scenarios are conceived taking into account appropriate safety factors . If under these worst-case assumptions a rele-... 

US-EPA has formed the Risk Assessment Forum, a standing committee of senior US-EPA scientists, to promote US-EPA consensus on difficult and controversial risk assessment issues and to ensure that this consensus is incorporated into appropriate US-EPA risk assessment guidance. To fulhil this purpose, the Forum assembles US-EPA risk assessment experts in a formal process to study and report on issues from a US-EPA scientific perspective. Major Fomm guidance documents are developed in accordance with the US-EPA s regulatory and policy development process and become US-EPA pohcy upon approval by the Administrator or the Deputy Administrator. The Risk Assessment Forum products include risk assessment guidelines, technical panel reports on special risk assessment issues, and peer consultation and peer review workshops addressing controversial risk assessment topics. 

The overall concept of all of the following tools is that of risk analysis or risk assessment. Risk analysis helps to decide whether an aspect is GMP-critical or not. The risk analysis can be performed in a formal or more informal way. Following are two popular and import types of risk analysis. Another method, the fault tree analysis (FTA), has recently been used in the area of computer validation. This method is not described here, as it is a complex form of risk analysis. 

The normal method of calculation for company funds is to use the capital asset pricing model (CAPM). This was developed by share analysts keen to have a defence against accusations of negligence in selecting shares for clients as a means of assessing the real value of any share, in the form of risk and desirability. It essentially demonstrates one version of the direct proportionality between risk and return. 

Our arguments will be based partly on the difficulties of maintaining a strictly scientific role in such a politicised policy system as that of the EU and partly on the nature of risk assessment, which, in our view, has implications for risk management. Also, as shown by numerous empirical studies of public policy, if experts are to be influential in policy making, some form of advocacy is needed (Sabatier and Jenkins-Smith 1993). 

TERIS is useful clinically. It provides succinct, authoritative summaries and interpretations of information available on the teratogenicity of a large number of drugs and a few important occupational agents. No information is included on other forms of reproductive toxicity. The system is designed for use by health professionals who are familiar with the general principles of risk assessment and is intended to assist in the counseling of individual patients. 

The assessment, management and communication of risk typically forms three separate (but interlinked) processes (Figure 2.4a) [159, 160]. Certain aspects of risk assessment are purely scientific (e.g., physical chemistry tests) and some aspects of risk management are only technical (e.g., product standards), but overlaps do occur (Figure 2.4b). For instance, risk management options generally determine the depth and scope of the risk assessment24 [161]. 

Endpoint selection is perhaps the most critical aspect of this stage of risk assessment as it sets the stage for the remainder of the process. Any component from virtually any level of biological organization or structural form can be used as an endpoint. Over the last several years two types of endpoints have emerged assessment and measurement endpoints. 

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 risk models described herein for carcinogens are not yet much used outside the United States. Carcinogens tend either simply to be banned, where it is possible to do so, or are treated the way non-carcinogens are treated in the United States. The discussion of risk assessment as applied to non-cancer forms of toxicity is thus applicable to carcinogens in countries outside the U.S.A. 

The high efficiency of sanitary infrastructures in developed areas entails paradoxical consequences. As concentration of pathogens in the environment is usually low, the detection/quantification of infectious parasitic forms and risk assessing are difficult. However, foodbome infections keep a strong health and economic impact. In USA, benign gastric or enteric diseases are the second cause of absenteeism with an annual cost of about 20 billion dollars, hi this country, foodbome infections cause between two and 9,000 deaths per year (CDC 1994). 

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