first_imgErring on the side of dangerOn 1 Apr 2004 in Personnel Today As the HSE reinforces its commitment to improving workplacehealth and safety in the UK, we asks what part human error plays in the causeof accidents at work.  By Anne Harriss Recent statistics released by the Health and Safety Executive (HSE) showthat 226 people were killed at work in 2002/03. Although this is an improvementon previous years, Bill Callaghan, chairman of the Health and Safety Commission(HSC), stated: “It represents continuing failure. Worker fatalities are ablemish on a civilised society. They mark a failure of a basic human right – tohave our health and safety protected”.1 Employers have a statutory duty under Section 2 of the Health and Safety atWork. Act 1974 “to ensure as far as is reasonably practicable, the health,safety and welfare at work of all his employees.” They must therefore have systems in place that protect their staff fromworkplace accidents. Managers can only reduce the incidence of workplaceaccidents if they have an understanding of the principles of accidentcausation. Accidents are unplanned, unintended events and occur as a consequence ofhuman error, mechanical malfunctioning, or both. Such shortfalls may havearisen following errors in design or operation. Alternatively, they could bethe result of poor supervision or inadequate maintenance. There is a definite link between human behaviour and accident causation.After all, we are only human, and error is one of a number of human factors,which affects safety performance. This article aims to consider the part human factors and human error play inaccident causation, so that occupational health practitioners can use thisknowledge to help prevent accidents in the workplace. Human factors An understanding of human factors in the workplace – in other words howpeople function at work – is an important facet of accident prevention. The HSE describes human factors as the perceptual, mental and physicalcapabilities of people and the interactions of individuals with their job andworking environments, and the influence of equipment and system design on humanperformance. It also notes characteristics of the organisation which influencesafety-related behaviour at work.2 The effective management of human factors istherefore essential in risk management. Lord Cullen acknowledged the significance of human factors in his report forthe HSC, which followed the Ladbroke Grove Rail enquiry. This disaster, whichresulted in multiple fatalities, occurred when a ‘signal was passed at danger’(SPAD). Such signals are put in place to protect the public as they alert traindrivers of danger. The question must be asked why some drivers have passedthese signals, and put themselves and their passengers at risk. Has thisoccurred due to the driver’s recklessness, or could there be some other reason?Cullen comments that signals are passed at danger due to “thelimitations of human ability not adequately [being] taken into account [in workdesign].”3 This is a sad indictment of our railway system. It appears that one of thecauses of SPADs is a failure to see or adequately interpret track signals.Cullen emphasises the need for train drivers to have a clear view of all therelevant signals with the information from those signals presented in a waythat enables drivers to understand the message they are giving. In short:”signals require to be not only visible but also readable”.3 Therecan be no excuse for poor design. The Ladbroke Grove crash occurred just 18 months after another seriousaccident at Southall. Cullen refers to the recommendations following theSouthall rail crash that “all parties in the rail industry… supportreliable research into human behaviour studies relating to driverperformance.”3 He suggests a number of factors that could have a bearing on whether a traindriver passed a signal at danger, which include the standard of driver trainingand skill. However, the physical environment, signal positioning and clarity,and the driver’s visual ability also play an important role. Cullen refers tothese as the railway’s “human-machine system”. Each of these elementsplays an important part within OH practice as well. If organisations are to be successful in accident prevention, it isimportant that they are able to identify the link between the mistakes peoplemake, an appreciation of human factors and the accidents that result. Accidents appear to be caused by a complex interplay of human factors andpolitical and economic influences. Hale proposes that health and safetypreservation is a basic goal of ‘normal’ staff, but interestingly, some do notappear to perceive the risk to their safety. If the risk to safety is small andthe gains are great, then workers may trade off a slight increase in risk totheir safety against a larger short-term goal. Perhaps such people areinherently risk-takers, with obvious implications for health and safety in theworkplace. The influence of the organisation in both the causation and the preventionof accidents is of paramount importance, but often disregarded. The finger ofblame is frequently pointed at the individual who is considered to be the‘miscreant’. This approach is misguided; if the cause of the accident is notconsidered in the light of the complexity of all the possible influences, therewill always be a shortfall in safety management and accidents will be arecurring feature within the organisation. Safety management systems The Cullen report makes interesting, if harrowing, reading. Reference ismade to the “short-sightedness” in blaming workers directly involvedin operational or maintenance work, while ignoring the fundamental failureswithin an organisation’s management and decision-making functions. A safety management system must acknowledge the part played by humanbehaviour in risk management. Safety objectives must be set and there must beeffective communication at both individual and organisational levels. Totalcommitment from management at all levels is essential, and‘safety-consciousness’ must become enmeshed within the culture of theorganisation. Safety management systems must incorporate evidence-basedpractice, and this includes an appreciation of human behaviour. The behaviour model of Hale and Hale, developed in 1987 and cited by Boyle,proposes that people function within a ‘systems’ model.4 Hale and Hale proposed that accidents happen when people fail to dealappropriately with a situation presented to them. This incorporates theindividual working within the working environment and includes the concept ofinformation input and processing, ending with an output. Information isconstantly presented to the person who then acts on it. The elements of thesystem include the method by which information is presented, and how it isinformation is then perceived and processed by the worker before they takeaction. The throughput can be affected by a number of factors, includingattributes of the individual, the climate of the organisation and workingconditions. The failure may be the fault of the person, the situation (whichcould include a faulty plant) or both. Unfortunately, safe working practices depend heavily on worker behaviour,which, by its very nature, is inconsistent. Behaviour is influenced by a number of physical and psychological factorsincluding the worker’s personality, knowledge and previous experience. Performance can be adversely affected by stress, illness, medication andfatigue, not to mention the general working environment. Poor performance maybe exacerbated by poorly designed equipment, and safety can be furthercompromised by poor standards of hazard control. It is not difficult to see howa noisy, poorly-lit working environment may contribute to the making ofmistakes. Domino theories of accident causation There are a number of domino theories, but their premise is that errorsoccur within the context of the organisation.4 Heinrich suggests there is a sequence of events leading up to an accident.5He proposes this sequence is set up rather like a line of upstanding dominoes,so that as each one falls it triggers a chain reaction as follows: i) The ancestry and social environment (character traits and attitudes),leads to ii) the fault of a person constituting the proximate reason for iii) the unsafe act or hazard which results in iv) the accident, which leads to v) the injury. Heinrich suggests that accident prevention should aim to eliminate theunsafe act/hazard represented by the middle (third) domino so that the chaincan be broken. This theory can be criticised as it assumes an accident results in injuryand it does not allow for the influence of management in accident prevention.Bird and Loftus propose a more superior model as they note the importantinfluence of management: i) Lack of control by management permits ii) basic causes (personal and job factors) which lead to iii) immediate causes (including substandard practices/conditions/errors)which are the proximate causes of iv) the accident, which result in v) the loss (minor, serious or catastrophic).5 Accidents and human error The part management plays in accident prevention is paramount, because notonly does it set the budget, specify and maintain plant and devise safe systemsof work, but it is also responsible for the recruitment, training andsupervision of human resources. And an important element of successful healthand safety management includes addressing the human factors – because accidentsoften result from uncorrected errors. For example, in the case of railway accidents, signalling errors are themost frequent cause of train accidents. Signal-related mistakes includefailures to confirm or detect a signal, and errors in perceiving orinterpreting the signal correctly. Since the Ladbroke Grove accident, the HSE has produced monthlypublicly-available reports on the incidence of SPADS, displayed on its website.The total number of serious SPADs in 2002/03 was 144, a 15 per cent improvementon the previous year and a 26 per cent improvement on the six-year average.6Although this is a heartening improvement, it is still 144 incidents too many. The Ladbroke Grove accident was a serious incident resulting in loss of lifeand serious injuries, but a multitude of less dramatic accidents occur on adaily basis. To attempt to reduce the incidence of errors in the workplace, itis important to appreciate what underpins them. Stranks refers to the threebasic categories of errors: Skill-based errors: these occur while carrying out fairly routine tasks andresult in slips, lapses and periods of inattention. They occur among highly-skilledpeople and often seem to be a case of familiarity breeding contempt. Rule-based errors: these occur when there is a set procedure, which shouldbe followed with a set of rules used. A rule-based error either occurs when aninappropriate rule is made, or the worker applies the rule incorrectly. Knowledge-based errors: these occur when a new problem has to be solved bygoing back to first principles. Mistakes occur as part of an ineffectiveproblem-solving process.7 The consideration of the capabilities of workers and their potential forerror are important factors when selecting people to undertake tasks. However,this is only one side of the coin. Accidents may also occur as a result of one or more of the followingelements: – Poor job design, leading to an unsafe system of work – Poorly-designed equipment – Equipment that malfunctions following inadequate maintenance – Inconsistencies in human behaviour. Reason notes that errors may not be immediately obvious and may lie dormantfor a period of time – only becoming apparent when they combine with otherfactors to cause a system failure.8 He equates these to ‘pathogens’, which arerather like micro-organisms in the human body, which only take over to cause adisease process when other conditions permit them do so. Organisational safety culture An otherwise safe system of work may become unsafe for reasons other thanerror. For example, a worker may deliberately take short cuts and not followthe safe systems of work put in place. Some may tend to take the path of leastresistance – particularly if violations go unpunished. If a safety procedureappears trivial and is rarely sanctioned, workers may be tempted not to followsafety guidelines. The 1986 Chernobyl nuclear disaster is one example, as theoperating circumstances resulted in deviations from what was until then aprescribed safe system of work. Several human factors played their part in the disaster some 20 years ago,which had far-reaching effects across Europe. The Chernobyl reactor wasuranium-fuelled and water-cooled. The explosion occurred when an experiment wasundertaken that required the deliberate removal of layers of protection thatwere designed into the system. Ironically, the experiment’s purpose was to improve levels of safety byensuring a constant supply of water to cool the reactor’s uranium fuel rods.The experiment, which was designed to avoid overheating, actually causedoverheating to occur.9 Operating the reactor under unsafe conditions led to serious instabilitieswithin the system. There were intrinsic fundamental design flaws, managerialfailures and transgressions of operational rules intended to prevent this typeof overheating from happening. Glendon and McKenna note that the Chernobyl operators were highly-regardedtechnicians, and the scientists were electrical engineers.10 Those running the experiment wished to solve a technical problem, with theoperators’ aim being to complete the test as quickly as possible. Theyapproached the experiment with the attitude that the test would bestraightforward and they would be able to run it with a ‘process feel’, ratherthan following the theoretical principles of nuclear physics. It is surprisingthat the report of the disaster produced by the Russian authorities identifiedthat the engineer in charge knew very little about nuclear reactors. It appears that the reactor operators and engineers assumed that the othergroup knew best, but neither demonstrated an appreciation of the possibledangers. Adverse outcomes did not appear to be considered – operator actionssuggest that they believed their tests were being conducted in a safe manner.It is likely that anyone with doubts failed to voice them, and instead wereprepared to ‘go with the flow’. This accident clearly demonstrates a combination of latent errors within thesystem, exacerbated by rule-based errors as outlined above. The organisationalculture did not appear to discourage risk-taking where there were other morepressing priorities. On this occasion, safety did not have a high enough priority. The HSEidentifies that the operators failed to distinguish between small and largerisks, with devastating consequences for human life and the environment.2 This clearly identifies the implications of an ineffective organisationalsafety culture with scant regard for the importance of human factors. Inaddition, there were flaws in the plant design and poor systems of work. To reduce the likelihood of a disaster like Chernobyl, it is important thatsources of foreseeable error are designed out of the equipment andwork-processes. Plant and systems of work should be ‘fail-safe’ – for example,become inoperable if operated under unsafe conditions. In the case ofChernobyl, when the system failed it caused danger rather than failsafe deviceskicking in, with fatal consequences. If accidents are to be prevented, a commitment to health and safety must beembedded within the organisational culture. This can only occur if a positiveattitude to health and safety permeates down through each management layer fromthe very top of the management structure. Management’s insistence on safetymust be continuously visible. Safety will deteriorate if procedures and safesystems of work are lax, and workers are discouraged from working to safetystandards by production targets. If management takes no action to enforcesafety, workers will fail to change their behaviour because unsafe practicesappear to be acceptable to the organisation. Conclusion This article demonstrates that accident causation is inextricably linked tohuman factors and human error, operating in the context of the organisation. To fulfil its responsibility to ensure a safe working environment,management must make safety a high priority. A safety management system is themeans by which the organisation controls risk through the management process.It would be na‹ve to suggest that all accidents could be prevented. Managersshould instead reflect on how errors could be reduced. They must be able toapply an understanding of human factors, be prepared to select appropriatestaff, safe equipment, and devise safe systems of work. They may also of courseseek assistance from OH practitioners in order to do this effectively. Anne Harriss is the OH course director at London South Bank University References1. HSE (2003) c03038.htm 2. HSE (1989) Human Factors In Industrial Safety London: HMSO 3. Health and Safety Commission ( 2001) The Ladbroke Grove Rail Inquiry –Part 1 Report, Suffolk: HSE Books 4. Boyle, T (2000) Health and Safety Risk Management, Leicestershire: IOSH 5. Stranks, J (1994) Human Factors and Safety, London: Pitman Publishing 6. HSE (2003) 7. Stranks, J (1994) Human Factors and Safety, London: Pitman Publishing 8. Reason, J (1990) Human Error, Cambridge University Press 9. Haynes, . Bojcun, M (1988) The Chernobyl Disaster, London: Hogarth Press 10. Glendon, I, McKenna, E (1995) Human Safety and Risk Management, London:Chapman and Hall Comments are closed. Previous Article Next Article Related posts:No related photos.last_img