Prevention and control strategies
Helen Chambers, Health & Safety Laboratory, UK
- 1 Introduction
- 2 Role and necessity of prevention and control strategies
- 3 Principles of prevention and control
- 4 Assessment of effectiveness of prevention and control strategies
- 5 Conclusions
- 6 References
- 7 Links for further reading
Every year millions of people in the European Union (EU) are injured at work or have their health seriously harmed in the workplace. Occupational accidents and diseases cause great human suffering and loss and the economic cost is also high. Prevention is the guiding principle for occupational safety and health (OSH) legislation in the EU. In order to avoid accidents from happening and occupational diseases from occurring, EU wide minimum requirements for safety and health protection at the workplace have been adopted across the Member States. This article provides an overview of prevention and control strategies.
Role and necessity of prevention and control strategies
The concepts of risk assessment and risk management are fundamental to prevention and control of risks to safety and health in the workplace. The key aspects of risk assessment include making sure all relevant risks are taken into account, checking the efficiency of the safety measures adopted, documenting the outcomes of the assessment and reviewing the assessment regularly to keep it updated. Workers have a right to reduction in ill health and accidents given that these things can be prevented or reduced if risk assessment and risk management are done.
In 2003, the International Labour Organization (ILO) published a global strategy on OSH. The strategy states that one of the fundamental pillars of a global OSH strategy includes the building and maintenance of a national preventative safety and health culture and the introduction of a systems approach to OSH management.
The ILO strategy includes the background for the need for a preventative culture including that the magnitude of the global impact of occupational accidents and diseases, as well as major industrial disasters, in terms of human suffering and related economic costs, have been a long standing source of concern at workplace, national and international levels. Significant efforts have been made at all levels to come to terms with this problem, but nevertheless the ILO estimated in 2003 that over 2 million workers die each year from work related accidents and diseases and that globally, this figure is on the increase.
It is difficult to get a more current overall statistical picture of ill health, injury and death caused by work as statistics are collected by individual countries or groups of countries and in different ways. In 2011, the reported number of fatalities due to work place accidents in the EU-27 was about 3,700 and some 2.7 Million workers suffered injuries which caused three or more absence days.
Principles of prevention and control
Principles deriving from the legislative Framework
Prevention means the act or practice of stopping something bad from happening. In the sense of OSH it means the avoidance of the risk or hazard at work. In contrast to prevention, control is the term to describe mitigation activities where the risk cannot be prevented. The principles of prevention and control strategies are enshrined in several pieces of EU Health and Safety (H&S) legislation. The OSH Framework Directive (89/391/EEC)  is of fundamental importance; it is basic H&S law which lays down general principles concerning prevention and protection of workers against occupational accidents and disease and establishes the framework for safety and health management at the workplace.
The Framework Directive contains general principles concerning:
- prevention of risks,
- protection of safety and health, assessments of risks,
- elimination of risks and accidents,
- the informing, consultation, balanced participation in accordance with national laws and / or practices
- and training of workers and their representatives,
- general guidelines for the implementation of the said principles.
- obligations of employers, employees and other groups.
Article 6 of Directive 89/391 sets down the following general principles of prevention:
(a) avoiding risks;
(b) evaluating the risks which cannot be avoided;
(c) combating the risks at source;
(d) adapting the work to the individual, especially as regards the design of work places, the choice of work equipment and the choice of working and production methods, with a view, in particular, to alleviating monotonous work and work at a predetermined work rate and to reducing their effect on health;
(e) adapting to technical progress;
(f) replacing the dangerous by the non-dangerous or the less dangerous;
(g) developing a coherent overall prevention policy which covers technology, organization of work, working conditions, social relationships and the influence of factors related to the working environment;
(h) giving collective protective measures priority over individual protective measures;
(i) giving appropriate instructions to the workers.
Under article 16 of the Framework Directive other, more specific, directives are created. All the single Directives have in common that they share the principles and approaches of OSH risk management which are set out in the Framework Directive. Still they establish more detailed risk management measures with regard to certain hazards or risks at the workplace, e.g. the Chemical Agents Directive, the Directives on Physical Agents such as noise or vibration   and the Biological Agents Directive  or with relation to specific workplaces or typical tasks, such as display screen equipment and manual handling.
A complete list of the current European legislation on OSH and on OSH related fields including short descriptions can be retrieved from the legislation web portal of EU-OSHA. 
The Framework Directive 89/391 and the single Directives have been transposed into national legislation and provide a framework for dealing with all kinds of risks. Even outside specific regulation, the principles of the Framework Directive are still applicable. One example is an increasing number of workers exposed to psychosocial risks at work and affected by work-related stress. Also broader health issues are to be considered. The European Agency for Safety and Health at Work (EU-OSHA) have recognised that the prevention of psychosocial hazards is thus one of the key challenges for OSH specialists and policymakers in Europe.
Directive 89/391 is the most important EU legislation relevant to risk assessment. Risk assessment is the cornerstone of the European approach to prevent occupational accidents and ill health. It is the start of the health and safety management approach. If it is not done well or not at all the appropriate preventative measures are unlikely to be identified or put in place.
Risk assessment can be defined as "the process of evaluating the risk to health and safety of workers while at work arising from the circumstances of the occurrence of a hazard at the workplace".
The process can be described as a continuous improvement cycle which can be implemented in the management processes in the company. The fundamental steps in risk assessment are:
- Step 1: identifying hazards and those at risk
- Step 2: evaluating and prioritising risks
- Step 3: Deciding on preventive action
- Step 4: Taking action
- Step 5: Monitoring and reviewing
The employer must be in possession of an assessment of the risk in accordance with Article 9 of Directive 89/391/EEC. This applies to all kind of risks and may be concretised by the individual Directives. The assessment shall be kept up-to-date, particularly if there have been significant changes or if the results of health surveillance show it to be necessary.
The employer must take the necessary preventive measures set out in Article 6 of Directive 89/391/EEC and the risks must be eliminated or reduced to a minimum following the hierarchy of prevention measures. The specific protection, prevention and monitoring measures listed below must be applied if the assessment carried out by the employer reveals a risk to the safety and health of workers. The employer must ensure that the risk:
- is eliminated, or if not applicable,
- reduced to a minimum, preferably by substitution (e.g. replacing a hazardous task or chemical agent with a task or chemical agent which is not or at least less hazardous.
The employer must regularly control the efficiency of measures and the presence of hazards which may present a risk to workers’ health, e.g. in relation to the occupational exposure limit values and must immediately take steps to remedy the situation if exceeded.
Risk assessment requires a fundamental understanding of the terms hazard and risk. It also requires the person undertaking the risk assessment to be competent. Competence is particularly derived from appropriate training and experience.
A hazard is something (e.g. an object, a property of a substance, a phenomenon or an activity) that can cause adverse effects. For example:
- Water on a staircase is a hazard, because you could slip on it, fall and hurt yourself.
- Loud noise is a hazard because it can cause hearing loss.
A risk is the likelihood that a hazard will actually cause its adverse effects, together with a measure of the effect. It is a two-part concept and you have to have both parts to make sense of it. Likelihoods can be expressed as probabilities (e.g. 'one in a thousand'), frequencies (e.g. '1000 cases per year') or in a qualitative way (e.g. 'negligible', 'significant', etc.). The effect can be described in many different ways. For example:
- The annual risk of a worker in Great Britain experiencing a fatal accident (effect) at work (hazard) is less than one in 100,000 (likelihood);
- About 1500 workers each year (likelihood) in Great Britain suffer a non-fatal major injury (effect) from contact with moving machinery (hazard); or
- The lifetime risk of an employee developing asthma (effect) from exposure to substance X (hazard) is significant (likelihood).
Once the risk has been assessed a decision needs to be made on what new measures (if any ) need to be introduced in order to reduce the residual risk, taking into account what is regarded as good practice as a guideline. The key point is that wherever preventative measures are to be taken they should improve the level of protection afforded to workers with regard to safety and health. Where possible it is particularly important that decisions of this type should be made at the design or purchasing stages of new processes, plants, products and procedures.
Safety and health management systems
Commonly, risk assessment and all kind of prevention and control measures are embedded in the management process landscape or in management systems. OSH management systems derive from the Total Quality Management approach, specifically those with Quality Management Systems according to the ISO 9000 standard.
The method is based on the 'Deming cycle', which consists of an iterative process of four steps, known as 'Plan, Do, Check and Act (PDCA)'. The involvement of top management in all steps of the process is essential for an effective management system. Risk assessment is the most important in the 'Plan' stage. The preventive and corrective measures should be carried out under participation of employees ('Do'). Performance measures and corrective and preventive action are the essence of 'Check'. 'Act' centres around the management review, taking into account OSH performance measures.
The most common standard for safety and health management systems is OHSAS 18001. In 2001, the International Labour Organisation (ILO) also published OSH MS Guidelines. Recently, the approaches were broadened by including health aspects. For example the World Health Organisation (WHO) published a model for 'healthy workplaces' with has many of the characteristics of an OSH MS.
Hierarchy of prevention and control measures
Main article: Hierarchy of prevention and control measures
Risks should be avoided/eliminated and (if not possible) reduced by taking preventative measures, in order of priority. The order of priority is also known as the hierarchy of control. There different hierarchies of prevention and control measures which have been developed by different institutions. Common are five steps in the hierarchy of control in accordance to the BS OHSAS 18001 management system.
The five steps are:
Step 1 Elimination: Elimination of hazards refers to the total removal of the hazards and hence effectively making all the identified possible accidents and ill health impossible. The term 'elimination' means that a risk is reduced to zero without a shifting it elsewhere. Elimination is the ideal objective of any risk management. This is a permanent solution and should be attempted in the first instance. If the hazard is removed, all the other management controls, such as workplace monitoring and surveillance, training, safety auditing, and record keeping will no longer be required.
Step 3 Engineering Controls: Engineering controls are physical means that limit the hazard. These include structural changes to the work environment or work processes, erecting a barrier to interrupt the transmission path between the worker and the hazard. Local exhaust ventilation (LEV) to control risks from dust or fume is a common example as is separation of the hazard from operators by methods such as enclosing or guarding dangerous items of machinery/equipment. Priority should be given to measures which protect collectively over individual measures.
Step 4 Administrative Controls: Also known as organisational measures administrative controls reduce or eliminate exposure to a hazard by adherence to procedures or instructions. Documentation should emphasise all the steps to be taken and the controls to be used in carrying out the activity safely.
Step 5 Personal Protective Equipment (PPE): PPE should be used only as a last resort, after all other control measures have been considered, or as a short term contingency during emergency / maintenance / repair or as an additional protective measure. The success of this control is dependent on the protective equipment being chosen correctly, as well as fitted correctly, worn at all times and maintained properly.
The reason that the use of PPE is at the bottom of the hierarchy of controls and is effectively a last resort is because of the higher likelihood (compared to controls higher up the hierarchy) of failing to danger because they place so much reliance for their success on the individual - be that in terms of them actually using the PPE or how well they use it or it actually fits them.
Figure 1: Hierarrchy of Controls
Source: machinery safety
When applying the hierarchy of prevention and control measures one should have in mind the legal requirements. In the context of prevention and control measures, the legal framework prioritises avoidance and elimination of the risks at source clearly over reduction.
Following the EU legislation, "reduce the hazards and the risk" also has a double implication, which is unfortunately not really apparent at first glance in the above mentioned OHSAS 18001 hierarchical system: If it is not possible to avoid the risks or eliminate the hazards, then the next step has to be to reduce/minimise the hazards AND to separate the remaining hazards from the workers.
Equally important, risk must not be transferred to another area; for example by providing exhaust ventilation of toxic substances in such a way that the discharge poses a risk to another workroom or to the public off-site.
Also note that as you go down the list of options, the controls become less reliable, more costly and require more work to ensure they are maintained. In most situations, the actual method for controlling the risk is a combination of options in the hierarchy. Training of workers should be associated with all steps and is fundamental to prevention and control.
Assessment of effectiveness of prevention and control strategies
European directives or national legislation establish that the employers have a duty to ensure the safety and health of workers in every aspect related to the work. The employers have responsibilities not only to take the necessary measures, but also to assure an improvement in the level of protection afforded to workers. Guidelines issued by national OSH authorities in OSH at workplace describe the elements of an OSH management system model, subjected to periodic audits that could conduct to success in implementation of legislation. An audit is defined as a systematic, independent and documented process for obtaining evidence and evaluating it objectively against standards to determine to what extend the defined audit criteria are fulfilled.
Systematic OSH management and periodic audit help to fulfil OSH legislation and to improve OSH performance in the company. It is essential that inspection or audit or other management systems are properly applied and maintained in order that risks are managed effectively. An example of a management systems approach is EU; BS18001. This will include audit, training, communication, and having a risk register as well as an accident or even a near miss log.
Practical examples of assessment of effectiveness of prevention and control strategies
Examples of assessment of effectiveness of control measures include the measurement of worker exposure to hazardous substances followed by appropriate comparison with relevant exposure standards. Where engineering controls such as local exhaust ventilation (LEV) are being used to manage the risk of worker exposure to hazardous substances the performance of the LEV can be assessed by quantitative measures such as measurement of velocity of airflow at the face of booths and in pipework and also use of qualitative measures e.g. the use of smoke or other ‘tell tales’ to demonstrate whether contaminants are being captured effectively. When controlling the effectiveness, one should also check that risks are not only shifted from one work station, area or activity to another or replaced by another risk.
The degree of risk reduction is not always quantifiable. However, when measuring OSH performance in an organisation, both leading and lagging indicators can be used. For example, a quantitative calculation of the impact of the risk reduction measure could be feasible in cases that apply to a large number of workplaces and where there is an easily quantifiable risk such as the number of accidents. Other examples for lagging indicators are production days lost through sickness absence, number incidents or near misses in a certain time span, or complaints of workers about work that is carried out in unsafe or unhealthy conditions. Leading indicators can be percentage of OSH projects and activities that are finalised on time, percentage of management meetings wherein OSH is addressed, or percentage of managers and workers that received OSH training.
Principles of prevention and control underpin management of risks to health and safety at the workplace. These are well established principles and widely applicable. The focus of action and consideration should be given to prevention of risk in the first place, particularly in terms of elimination at the source or substitution e.g. of a less hazardous substance, rather than immediately considering risk management/control measures. Psychosocial issues and general health issues should also be considered along with the safety risks and risks to health caused by physical, chemical, and biological agents.
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Links for further reading
EU-OSHA – European Agency for Safety and Health at Work, Healthy Workplaces Good Practice Awards 2014–2015: Managing stress and psychosocial risks at work. Luxemburg, Bilbao 2015. Available at 
HSE - Health and Safety Executive, Successful Health & Safety Management, HSG 65. Liverpool 1997. Available at: 
HSE - Health and Safety Executive , Five Steps to risk assessment. INDG 163 (rev 3) 06/11. Liverpool 2011. Available at: 
HSE – Health and Safety Executive, 'Application of QRA in operational safety issues'. Research report 25, Liverpool 2002. Available at: 
Gallagher, C., Underhill, E., and Rimmer, M., 'Occupational safety and health management systems in Australia: barriers to success', In: Policy and Practice in Health and Safety 10/2003, pp.67-81. Available at: 
Gardiner, G., & Harrington, J.M., Occupational Hygiene, 3rd Edition, Blackwell Publishing, 2005.
Masi, D and Cagno, E., 'Barriers to OHS interventions in Small and Medium-sized Enterprises'. In: Safety Science 07/2014, pp. 71-87. Available at: