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Wednesday, 30 March 2011 15:20


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According to International Labour Office statistics, 120 million occupational accidents occur annually at workplaces worldwide. Of these, 210,000 are fatal accidents. Every day, more than 500 men or women do not come home because they were killed by accidents at work. These are dramatic numbers which draw fairly little public attention. Considering the fact that accidents take a considerable economic toll from nations, companies and individuals, accidents do not get much publicity.

Fortunately there are people working with a sense of purpose, often behind the scenes, towards understanding and managing safety and accident prevention better, and their efforts have not been wasted. Our understanding of accident prevention and safety is on a far higher level than ever before. Many world-class researchers and safety practitioners share this new knowledge with us through their articles in this Encyclopaedia. During the past twenty decades, knowledge about accidents has evolved considerably. We have left behind the simplistic model of dividing behaviour and conditions into two categories: safe or unsafe. The rigid belief that any activity can be placed into either category has been put aside as more sophisticated systemic models have been developed and proven effective in managing safety.

The important observation is that two safe conditions which by themselves are safe, may not be safe together. Workers are the connecting link, as their behaviour changes according to the environment and their physical surroundings. As an example, power saws caused many accidents when they came into use in the 1960s due to a hazard known as “kickback”, which takes the operator by surprise when the chain-saw blades hit a branch, knot or harder point in wood. Kickback killed and injured hundreds of people before a guard was invented to protect the operator. When Sweden implemented regulations requiring the kickback guard, the number of power saw injuries went down from 2,600 in 1971 to 1,700 in 1972. This was a major breakthrough in power saw accident prevention.

Every user of power saws knows from personal experience that this noisy, vibrating and obviously sharp cutting tool appears to be very dangerous to use, and the beginner operator is very cautious. However, after hours of experience operators lose their sense of any hazard and start handling the saw less carefully. The kickback guard may produce a similar effect. Operators who know kickback is possible try to avoid it. When operators know that there is a mechanical device preventing the saw from hurting them in event of kickback, they become less cautious. In another forestry industry chain-saw example, studies have shown that leg protection makes workers less careful and they expose themselves more often to kickbacks, because they believe they are protected.

Despite the fact that kickback protection has helped prevent injuries, the mechanism is not straightforward. Even if these protective arrangements have been successful, in the final analysis their effects do not have a linear relationship with safety. Two safe conditions, kickback guard and leg protection, do not double the safety. The normal arithmetic of one plus one equals two (1 + 1 = 2), does not apply in this case, as one plus one makes less than two. Fortunately, one plus one (1 + 1) makes more than zero in some cases. In other cases, however, the sum may even be negative.

These are phenomena which safety practitioners have started to understand better than before. The simple division of behaviours and conditions into safe and unsafe does not lead very far toward prevention. The credit for progress has to be given to systems management. After understanding that humans, their tasks, their equipment and the environment make up a dynamic system, we have made considerable progress towards more effective accident prevention. The following examples demonstrate the dynamic nature of people and work. If one component is changed, the others do not remain the same, and the ultimate safety effect is hard to estimate in advance.

In aviation and in other highly engineered and automated systems, we have seen that increased automation may not necessarily result in improved safety. For example, operators may not get enough practice to maintain their skills in a highly automated system. When they then are required to intervene, they may not have the necessary competence or ability.

Some paper manufacturers have indicated that younger employees do not understand the functions of a paper machine as well as the older employees. The older employees have operated non-automated machines, and they have seen how these work. The new automated machines are operated from control rooms through computer keyboards and screens. The operators do not know the exact location of each component of the machines they operate. Therefore they may bring a component into a state which, for example, causes a hazard to the maintenance people in the vicinity. A technical improvement in the machinery or controls without simultaneous improvement in operators’ skills, knowledge and values may not result in improved safety.

Accident prevention has been traditionally based on learning from accidents and near accidents (near misses). By investigating every incident, we learn about causes and can take actions towards mitigating or removing the causes. The problem is that we have not been able to develop, in the absence of sufficiently good theories, investigation methods which would bring up all the relevant factors for prevention. An investigation may give a fairly good picture about the causes. However, this picture is usually relevant only for the specific case investigated. There may be conditions and factors which contributed to the accident whose connections the investigators do not recognize or understand. Generalizing from one accident to other situations bears a degree of risk.

The good news is that we have made considerable progress in the area of predictive safety management. A number of techniques have been developed and have become routine for industrial safety and risk analysis. These techniques allow us to study industrial production plants systematically for the identification of potential hazards and to institute appropriate action before anything happens.

The chemical and petrochemical industries have shown leadership in this area worldwide. As a result of major catastrophes, such as Bhopal and Chernobyl, the use of the new predictive techniques has increased. Remarkable progress has been made since the mid-1970s in the area of safety. Many governments have also been leaders in making safety analysis mandatory. Sweden, Finland, Japan and the Federal Republic of Germany have all reduced fatal occupational accidents by 60 to 70% during this time. Many other countries show similar progress. Now, the challenge is to transfer our knowledge from research into practical applications and further improve our preventive efforts.

One of the new steps in safety management is the notion of safety culture. It may be a difficult concept, since culture is not a visible entity. It is an abstract concept prevailing within an organization or society. There are no direct ways of adjusting it. Safety culture is, however, a crucial concept for understanding the possibilities of prevention. One of the goals of this edition is to explore this new concept.

This new edition of the Encyclopaedia provides a comprehensive review of accident prevention theories and models in order to develop better design and more effective preventive strategies. It is possible to prevent occupational accidents. We do not need to tolerate this unnecessary toll to our well-being and economy.



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