What causes accidents

Unsafe acts and unsafe conditions are often referred to as immediate or primary causes of accidents, because they are the most obvious causes and because they are usually directly involved or present at the moment the accident happens. Secondary causes are also important, although they are usually harder to seek out and identify. They are the failures of the management system to anticipate, and include lack of training, maintenance, adequate job planning and instruction, and not having safe systems of work in place. 

Some examples of unsafe acts and conditions are given below. 

Some of the reasons why people fail - to behave safely, to conform to policies and procedures, for example are discussed in Chapter 8. 

Inadequate or missing guards to moving machine parts Missing platform guardrails Defective tools and equipment Inadequate fire warning systems Fire hazards 

Ineffective housekeeping Hazardous atmospheric conditions Excessive noise 

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Line supervisors should be involved in accident investigations, basically because they are normally the people in direct contact with the worker and understand their problems, personalities, and capabilities. Involving snpervisors increases their responsibilities toward the accident prevention effort (see Figure 3.1). Supervisors are normally responsible for training, so becoming involved in investigations will make the supervisor more aware of what causes accidents as well as ways to prevent a recurrence. 

What sorts of beliefs do supervisors and managers have about what causes accidents and how does that affect how they try to manage them ... 

What causes accidents 44% of professionals believe the majority of accidents are attributable to human error. 22% disagree, and 33% are on the fence they neither agree nor disagree. 

Sodium hydroxide was introduced into a reactor containing 90 kg of ethylene oxide. The reactor detonated eight hours later. A study was carried out to try to understand what caused the accident. It showed that in similar conditions the temperature of the medium reaches 100°C when 13% of oxide is polymerised, then 160°C at 28% of conversion. At this stage, it takes sixteen seconds for the medium to reach a conversion rate of 100% and a temperature that reaches 700°C. 

Could that be so that the Universe was created with the preponderance of matter over antimatter We have no support for such hypothesis. Einstein remarked If that s the way God made the world then I don t want to have anything to do with Him [7]. Indeed, the contemporary Standard Model of Physics suggests that equal amounts of matter and antimatter were born during the Big-Bang. Where has the antimatter gone What causes the apparent asymmetry between matter and antimatter Obviously the antiparticles have been annihilated by particles - but apparently this process was not fully symmetric, since enough matter was left over for our Universe. We seem to be the result of an accident, caused by a a slight imperfection of Nature. 

Ask any group of people experienced in chemical plant operations what causes most chemical process accidents, and you will get a variety of answers including operator error, equipment failure, poor design, act of God, and bad luck. However, in the opinion of representatives of many of the large chemical and oil companies in the United States, these answers are generally incorrect. The Center... 

An underlying assumption of all accident models is that there are common patterns in accidents and that they are not simply random events. Accident models impose patterns on accidents and influence the factors considered in any safety analysis. Because the accident model influences what cause(s) is ascribed to an accident, the countermeasures taken to prevent future accidents, and the evaluation of the risk in operating a system, the power and features of the accident model used will greatly affect our ability to identify and control hazards and thus prevent accidents. 

This book suggests a new approach to engineering for safety that changes the focus from prevent failures to enforce behavioral safety constraints, from reliability to control. The approach is constructed on an extended model of accident causation that includes more than the traditional models, adding those factors that are increasingly causing accidents today. It allows us to deal with much more complex systems. What is surprising is that the techniques and tools described in part 111 that are built on STAMP and have been applied in practice on extremely complex systems have been easier to use and much more effective than the old ones. 

Behavior-based safety is based on one of the oldest and most outdated approaches to safety — the Heinrich premise that 88% of all industrial accidents are caused primarily by unsafe acts of persons [p. 1]. Behavior-based safety does not focus on what really causes accidents. Injuries and illnesses are caused by exposures to hazards. What do I mean by hazards Hazards include any aspect of technology or activity that produces risk. If the work methods designed and prescribed put employees at risk, those methods are hazardous [p. 5]. 

Modem jet airplanes are designed with highly redundant systems, which make accidents highly improbable. When they do occur, they are usually the result of a concatenation of discrete events—of mechanical or human failures—any one of which by itself would not likely cause a catastrophe. It is this unforeseen sequence of events, resulting from what accident theorists call the tight coupling of complex interacting systems, that causes accidents. 

One of the biggest obstacles to reporting a safety issue is that the employee is punished, which is a knee-jerk reaction deeply embedded in safety cultures. The excuse here is Well, I would rather discipline him than have to visit him in the hospital. After an accident people become very emotional, and line management automatically look for who caused the accident rather than what caused the accident. 

In 1997 a scientist at a nuclear research center in Russia placed a thin shell of copper on a sphCTe of highly enriched uranium-235. Suddenly, there was a huge burst of radiation, which turned the air hlue. Three days later, the scientist died of radiation damage. Explain what caused the accident. (Hint Copper is an effective metal for reflecting neutrons.)... 

Data about the strength properties of human tissue and structures often come from cadaver or animal studies. The data help in estimating the likelihood of injury or severe injury in some situations. The data may help in reconstructing certain accidents and considering the kind and extent of tissue damage. However, because the body and actual conditions of an accident are complex, it is difficult to use analyses to describe exactly what happened or what caused the resulting injuries. Injury analysis and autopsies by forensic physicians may identify conditions which can produce certain kinds of injuries. Figure II-I provides some data about human tolerance to impacts. 

The first steps in being able to prevent accidents from propagating is to understand the combination of factors that can initiate them, and what causes them to escalate [Ontario 1999]. The generally accepted theories of accident causation, for example Heinrich s domino theory [Heinrich 1931] and Reason s organisational accident theory [Reason 1997] may use different terminology, but they do all have common themes ... 

Despite their complexity, most accidents are preventable by eliminating one or more causes. Accident investigations determine not only what happened, but also how and why. The information gained from these investigations can prevent the recurrence of similar or perhaps more disastrous accidents. Accident investigators are interested in each event as well as in the sequence of events that led to the accident The accident type is also important to the investigator. The recurrence of accidents of a particular type or those with common causes show areas needing special accident prevention emphasis. 

First, we can prevent them by knowing what caused the accidents to happen in the first place. Accident investigators perform that task. The accident investigator determines the direct, indirect, and basic causes of an accident. But prevention does... 

All who undertake an inquiry to determine what additional actions may be taken to reduce serious injury potential will learn from R. B. Whittingham s The Blame Machine Why Human Error Causes Accidents. Whittingham describes how disasters and serious accidents result from recurring but potentially avoidable human errors. He shows how such errors are preventable because they result from defective systems within a company. 

Sutton s statement describes a necessity for superior results to be achieved. And safety professionals should be working toward influencing management that it is in their best interest to put processes in place to uncover, confront, and address hazards and the risks that derive from them. Never the less, realism with respect to the management practices in some companies must be acknowledged, as is discussed in the next section. Unfortunately, what R. B. Whittingham wrote in the Preface to The Blame Machine Why Human Error Causes Accidents speaks to what is sometimes actuality ... 

In a workplace of your choice, interview five people at various levels and find out what they believe causes accidents and injuries at woric. Report your results and comment on them based on your studies of the factors leading to accidents. 

As we have seen in Chapter 1, the vast majority of accidents are caused by people. Sometimes their behaviour is a result of ignorance, but more often it is not. For example, drivers are taught how to drive and have to pass a test, usually having both theoretical and practical elements, before they are allowed to drive unaccompanied. Despite this, road accidents continue to occur. Given that the majority of accidents are caused by knowledgeable people behaving in ways that lead to accidents, how can we understand what caused them to behave as they did ... 

Applying ICAM as a predictive tool allows the organization to identify and retain information on causal factors, so the organization remembers that the accident occurred, what caused it, and why procedures were changed. R. Wood (1997) states Beyond question, the most difficult and troublesome aspect of aircraft accident investigation is the determination of cause. ... 

The board should have broad powers to investigate what caused the accident and to develop recommendations to prevent further occurrences. An impartial individual should chair the board. The chairperson should be picked in accordance with Table 11.2. 

Minority reports (if necessary)— May be included if the board is not in 100% agreement to what caused the accident. This does happen, and for very large and severe accidents, it may be necessary to have a section to allow minority or contrarian reviews to be put forth. This is very important to show impartiality, transparency, and differing views. Bnt in the end, some sort of majority conclusion and recommendations must be made so that the company can move forward. 

What are some examples in which dusts composed of biological materials have caused accidents that have led to fatalities ... 

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