Hazard, Risk, and Danger

Three terms must be considered before evaluating a possible hazard hazard, risk, and danger. The word hazard refers to the existence of a potentially harmful condition. For example, if you re working with or near lead or carbon monoxide, you are in a potentially harmful situation, but are not necessarily in danger. The term risk describes the probability of harm, or the extent to which you are likely to be harmed. If the carbon tetrachloride you re working with is in a properly ventilated and closed tank and you don t have any contact with it unless while wearing gloves and/or a respirator, the risk is minimal. It is possible to measure the risk... 

To make representations to the employer on hazards, risks and dangerous occurrences in the workplace which affect, or could affect, the group of employees they represent... 

Overall Metabolic Processes. In general, metabolic processes which facilitate elimination of a pesticide from the body are considered desirable. This is based a great deal on our long history of associating toxicity with chemicals that accumulate in the body. Arsenic, lead, mercury and other metals substantiate these concerns as do more modern synthetic organic chemicals such as DDT and mirex. Because so many chemicals rapidly voided from the body are now known to be extremely hazardous, risks and excretion rates are evaluated very carefully. Still, storage of metabolites is not a positive characteristic even for those compounds like DDE whose danger, if any, as a body burden has not been established. 

HAZARD RISK Flammable dangerous fire hazard explosion hazard with air mixtures of ether vapors can form peroxide that detonate when heated decomposes on heating and on contact with water, producing toxic and corrosive fumes of hydrogen chloride and formaldehyde may generate electrostatic charges can ignite by electric sparks attacks many metals, resins and plastics NFPA code not available... 

HAZARD RISK Very dangerous fire hazard when exposed to heat or flame moderate explosion hazard when exposed to heat or flame attacks aluminum, iron and polyethylene vapor is heavier than air and may travel to ignition source, then flash back contact with caustics emits flammable and poisonous acetaldehyde gas decomposition emits irritating and highly toxic fumes of phosgene and hydrogen chloride NFPA Code H 2 F 3 R 0. 

HAZARD RISK Very dangerous fire and explosion hazard when exposed to heat or flame mixtures with dinitrogen tetraoxide may explode at 28°C formation of toxic vapors NFPACode H1 F3 R0. 

Yellow (black symbols and text) Hazard (risk of danger) bHfication of hazards (electrical, explosive, radiation, chemical, vehicle, etc.) Warning of threshold, low passages, obstacles... 

FIGURE 4.1 Hazard identification helps determine risk and danger. 

It is important that all hazards are identified, and that an assessment is made of the potential risk from the hazard. This allows for the determination of the real danger that exists. If a high degree of risk and danger exists, then efforts must be undertaken to alleviate or mitigate the potential danger (see Figure 4.1). 

The problem of roof support in U.S. and British coal mines illustrates the very real material presence of risk and danger in the context of a hazardous environment.Unfortunately, no method of roof support can provide 100% safety. All roof support systems eventually fail. To predict failure, miners must learn to recognize signs of imminent danger in whatever method of roof support they employ— just as they must sense other signs of danger in their environment. 

In addition to pollution episodes, risks may arise due to atmospherie oxygen eoneentrations fluetuating beyond its normal level of 21% posing health (page 72) or fire hazards. Eire and explosion dangers may also arise from the presenee of flammable gases, vapours, or dusts in die atmosphere (Chapter 6). 

Hazard, risk, failure, and reliability are interrelated concepts concerned witli uncertain events and tlierefore amenable to quantitative measurement via probability. "Hazard" is defined as a potentially dangerous event. For example, tlie release of toxic fumes, a power outage, or pump failure. Actualization of the potential danger represented by a hazard results in undesirable consequences associated with risk. 

Requirements for labelling of containers for supply may differ from those for conveyance. Key features of a supply label are to identify the substance (the chemical name in most cases) and any hazards and safety precuations. In Europe the classification, packaging and labelling of dangerous substances is covered by Directive 67/548/EEC as amended. This requires labels to identify appropriate risk and safety phrases (Tables 12.2 and 12.3) depending upon product properties. A substance is considered dangerous if in Part lA of an approved list or if it exhibits hazardous properties as defined in Schedule 1 for supply, or Schedule 2 for conveyance as shown in Tables 12.4 and 12.5. Substances not tested should be labelled Caution — substance not yet fully tested . Criteria for risk phrases are provided, e.g. as in Table 12.6 for toxic compounds. 

Professor Martel s book addresses specifically some of the more technical eispects of the risk assessment process, mainly in the areas of hazard identification, and of the consequence/effect analysis elements, of the overall analysis whilst where appropriate setting these aspects in the wider context. The book brings together a substantial corpus of information, drawn from a number of sources, about the toxic, flammable and explosive properties and effect (ie harm) characteristics of a wide range of chemical substances likely to be found in industry eind in the laboratory, and also addresses a spectrum of dangerous reactions of, or between, such substances which may be encountered. This approach follows the classical methodology and procedures of hazard identification, analysing material properties eind... 

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