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In company practice and in legislation, it is increasingly acknowledged that occupational safety and health (OSH) management should be performed systematically and continually. Implementing an OSH Management System (OSH MS) is the major strategy to achieve this.

What are occupational safety and health management systems?

Occupational safety and health (OSH) problems were initially perceived as mainly technical problems that required technical solutions. Later, organisational issues were recognised as being important, and more recently, human factors, behavioural and organisational culture issues have been identified as being important[1].

The increasing awareness of problems and solutions has been mirrored by the development of management practices. Initially, management of OSH focused on technical inspections, with the later inclusion of organisational, human factors and behavioural issues. Today, it is broadly acknowledged that all these factors are important and the management of OSH requires an integrated approach.

ISO Standard 45001 Occupational health and safety management systems — Requirements with guidance for use defines a management system as a set of interrelated or interacting elements of an organisation to establish policies and processes to achieve those objectives. An OSH management system is a management system or part of a management system used to achieve the OSH policy to prevent work-related injury and ill-health to worker(s) and to provide a safe and healthy workplace[2].

OSH MS combine occupational safety and health with management and ‘system thinking’. In ‘system thinking’, entities such as organisations or departments are considered as ‘systems’ which comprise a range of ‘elements’ (e.g. risk assessment and OSH competence). The ‘whole (the system) is more than the sum of its parts (the elements)’ and the interactions between the elements are just as important as the elements per sé.

The five basic characteristics of any OSH MS are:[3][4]

  1. It includes all components of OSH that are relevant to the members of the organisation and the business process.
  2. In principle, its functions are: (1) to increase the effectiveness of OSH management; (2) to guarantee compliance with existing legislation; and (3) to improve OSH performance. The OSH MS objectives are to be defined by the organisation and may include ethical, economic, legal and organisational goals. Not all OSH MS have similar objectives.
  3. It is a holistic approach, specifying and requiring implementation of a series of elements and (positive) interactions between them.
  4. It has provisions for system maintenance and continuity. The functioning of an OHS MS is evaluated on a regular basis (through OSH audits). A periodic review of its objectives and effectiveness is necessary to ensure continuous improvement.
  5. Its outputs (OSH performance) are important to the evaluation of the management system.

OSH MS help deal with complex issues, such as the ‘changing world of work’[5], the dynamics within organisations, and the interactions between management and employees. They lead to a better understanding of processes, problems and possible solutions, and enable the implementation of measures to reduce hazards and control risks[6].

The relationship between occupational safety and health management systems and legislation and governmental policies

Regulatory requirements now include a systematic management approach to control occupational hazards. The most prominent example is the EU framework directive from 1989[7]. Although it does not require companies to have an OSH management system, it does require them to have a range of elements of the system (i.e. management and workers involvement, a risk assessment and control process, and OSH competence). Within the EU, having a specific (process) safety management system in place is a legal requirement for the chemical process industries that deal with major hazards (the post-Seveso Directive).

Throughout various countries, government policies have supported the implementation of OSH management system. These include the exemption from regular screening inspections in Denmark[8] and the promotion of voluntary management systems in the UK[9]. Similar developments have taken place outside the EU. For example, OSH MS are embedded in the USA’s OSHA’s Voluntary Protection Programme[10].

The importance of standardisation

In the 1990’s standardised approaches for OSH MS were developed that made use of the experiences with Total Quality Management, specifically those with Quality Management Systems according to the ISO 9000 standard.

Following these developments, and after fierce debates[11], OSH management system standards were developed. OHSAS 18001 (first version 1999, updated in 2007) has long been the main standard, but it was replaced in 2018 by ISO Standard 45001 Occupational health and safety management systems — Requirements with guidance for use[2]. OHSAS 18001 was officially withdrawn in 2021 as companies certified under OHSAS 18001 had three years to make the migration to ISO 45001. In 2001, the International Labour Organisation (ILO) also published OSH MS Guidelines[12].

Traditionally OSH management systems, although explicitly addressing both occupational health and safety, tended to focus more on safety than on health [6][13][14]. However, over the last decades, there is a move for OSH MS to address occupational health issues using comprehensive and systematic approaches. The World Health Organisation (WHO) published in 2010 a model for “healthy workplaces" with many of the characteristics of an OSH MS[15]. More recently, ISO has developed a standard for the management of psychosocial risks (ISO 45003:2021[16]), which can be considered a supplement to the ISO 45001 standard.

The ISO 45001 standard is based on the harmonised structure that is used for all ISO management system standards. These standards specify steps that organisations can implement to improve their performance based on a continuous cycle of self-evaluation, correction and improvement and on employee commitment and management leadership [17]. All management system standards have a common, harmonised structure, making it easier for organisations to develop an integrated management system. The structure is based on the ‘Deming cycle’, which consists of an iterative process of four steps, known as ‘Plan, Do, Check and Act (PDCA)’. Leadership commitment is essential in all steps of the process. Risk assessment is the most important in the ‘Plan’ stage. The awareness and participation of employees with relevant skills and competences, and available resources is critical for 'Do'. Performance measures and corrective and preventive action are the essence of 'Check', while ‘Act’ centres around the management review, taking into account OSH performance measures. An overview of the key elements of ISO 45001 is shown in table 1.

Table 1 - Key elements of ISO 45001

Plan Determine OSH objectives, processes and resources required to achieve results based on an understanding of the organisation's context including OSH risk and opportunities: - context, needs and expectations of stakeholders; - scope, OSH policy, leadership commitment, roles and responsibilities; - risk assessment; - objectives and planning; - support and resources.
Do Implement and control the processes: - implementing and monitoring prevention measures in accordance with the hierarchy of controls; - keeping documented information; - controlling processes such as change and outsourcing; - emergency preparedness.
Check Monitor, measure and evaluate OSH activities and processes: - criteria and monitoring processes; - internal audit; - management review.
Act Take actions to continually improve:   - managing incidents and non-conformities (reporting, investigating and taking action); - addressing audit findings; - continual improvement process.

Source: ISO 45001[2]

Processes of continuous improvement

An important feature of OSH MS is the process of continuous (or continual) improvement.
Figure 1: OHS management as an iterative process for continual improvement
Figure 1: OHS management as an iterative process for continual improvement

Any OSH MS implies an iterative process, with each cycle in the process aiming to contribute to OSH improvement. This is illustrated in Figure 1 based on the OHSAS 18001 model [18]. and also the core principle of the ISO 45001 standard as well as all other Management systems standards.

The idea of continuous improvement (stemming from the ‘PDCA’ cycle) is challenging and promising. However, in practice it is often not easy to achieve continuous improvement in OSH performance.

One reason is that it presupposes a stable or constant work environment. If no new risks are introduced and the existing risk control measures are always functioning well, further improvement will contribute to an overall improvement in OSH. However, in everyday practice, organisations are dynamic and evolving. Reorganisation within the company and the introduction of new technologies and ways of working may imply drastic changes. People may leave the organisation and may not be replaced – perhaps with them relevant OSH knowledge disappears. Such developments may alter the process of continuous improvement to a process of ‘trying to keep up with changes’.

The second reason is that the process of continuous improvement presupposes a process of organisational leaning (with respect to OSH management). Such organisational learning processes are possible, but are not an automatic result of implementing an OSH MS. For an interesting analysis of the process of continuous improvement and learning, see[19].

Reasons for implementing an occupational safety and health management system

There are several reasons why organisations might want to implement an OSH MS. The main reasons are:

  • to systemise OSH Management;
  • to optimise prevention;
  • to improve OSH performance;
  • to reduce possible future liabilities;
  • to assure compliance with legislative requirements;
  • to create organisational benefits, whether economic or other;
  • to show that the organisation cares for its employees and is a good employer;
  • to benefit from regular external feedback from third party auditors;
  • to reduce the likelihood of inspection by the labour inspectorate;
  • to demonstrate to customers and external stakeholders that an OSH MS is in place;
  • to be transparent about the company’s corporate social responsibilities.

The option of certification

The ISO management standards imply the option of third party certification. Third party certification means that an independent and competent agency (e.g. DNV, Lloyds, BVQI, etc.) confirms after a dedicated audit that there can be ‘justified confidence’ that the management system is functioning well, and that the organisation complies with all relevant requirements. Such agencies evaluate the ‘system of plans and words’ (in the OSH Management Handbook), as well as the ‘system of associated practices’ in the organisation. Where these two ‘systems’ do not correspond, the practices should be considered more important than the paper work, as these determine the occupational safety and health performance. The certification bodies have to meet the requirements of ISO/IEC TS 17021 Conformity assessment - Requirements for bodies providing audit and certification of management systems, part 1 Requirements and part 10 Competence requirements for auditing and certification of occupational health and safety. They carry out the audit and evaluation according to the guidelines of the International Accreditation Forum (IAF)[20].

Having a certified occupational safety and health management system in place is increasingly becoming a business-to-business requirement. Since the early 1990’s, this development has also raised the issue of integrated Management systems, wherein OSH MS are integrated with quality and/or environmental management systems, and business processes[21][5][22]. According to the ISO survey 2020 worldwide around 190,000 businesses have obtained an ISO 45001 certificate. This makes the standard the third most implemented and certified standard behind standard 14001 Environment (348,473 businesses) and standard 9001 Quality (916,842 businesses)[23].  

The certification regimes associated with OSH MS have been criticised, e.g. for increasing the cost to businesses and for becoming an ‘aim in themselves’[11], for failures in the broader certification regime[24]and in the associated market mechanisms[25], and for problems with the quality of the essential auditing process[26][13].

Certification can be attractive for companies, especially as it demonstrates to customers and the labour inspectorate that they are addressing occupational safety and health issues continuously and systematically. However, the certification process can become an ‘aim in itself’, when 'having the certificate' becomes more important than the improvements in OSH performance. Therefore, several companies choose to implement a ‘certifiable management system’, but refrain from certification. They then enjoy the benefits of a good and auditable OSH management system, while avoiding the danger of the certification process becoming a ’means to an end’.

The impact of occupational safety and health management on OSH performance

An occupational safety and health management system influences the occupational safety and health performance of the organisation. A management system only functions adequately when there is a continuous and systemic control of all activities and influences relevant to OSH.

Beneficial effects on health and safety performance can be expected in the short-term from improvements during the implementation process (when the management system is put in place), and in the long-term from the potential of the continuous improvement process over time[19].

Nevertheless, there are debates as to whether OHS MS have a positive effect on health and safety or not. On the one hand, proponents almost take it for granted that an occupational safety and health management system will automatically lead to better health and safety performance, as is suggested in the ISO 45001 standard. On the other hand, critics have used words, such as “scam", “fraud", “bureaucracy" and “paper tigers", to describe management systems and pointed out that workers lose influence[27]. In reality, the impact of OSH MS is depending on several contextual factors[28] and therefore ambiguous.

It is well established that occupational safety and health management system can be a valuable method for the improvement of health and safety[4]. Whilst OSH MS can be used as a tool for management, how that tool is used depends primarily on the management’s ambitions (the OSH objectives). These ambitions can range from ‘having the certificate’ to becoming ‘world class in health and safety’. OSH MS can also be regarded as an enabling methodology which can be used to serve different purposes, and can be associated with different contents, depending on the company and its ambitions, culture and history[6].

OSH MS imply an on-going ‘PDCA’ process, but planning and the associated paper work is often easier to accomplish compared to the rest of the cycle. Especially after reorganisations the paper work remains intact, but practices and responsibilities may have changed, leading to the danger that occupational safety and health management system become just a paper exercise. The changes to the way a business operates, societal developments, shifting priorities and risk perceptions of internal and external stakeholders, influences the functioning of OSH MS over time. Occupational safety and health management system also require continuous interpretation, adaptation, anticipation and monitoring, e.g. with regard to newly emerging risks, such as psychosocial risks or those stemming from nanotechnology. Therefore, the functioning of OSH MS is always dynamic and complex, and sometimes implies uncertainties, and ambiguities.

Despite the concept of ‘management system’ suggesting that it is an issue for management only, worker participation in OHS MS is regarded as essential[29][14].

In summary, the ambition to improve OSH substantially, the commitment of management, the participation of workers and the continual adaptation to changing circumstances are essential for effective OSH MSs. This has implications for the scientific evaluation of the effectiveness of occupational health and safety management system. It is not useful to prove once and for all that OHS MS are beneficial for managing health and safety, when such contextual factors are not taken into account. An OHS MS cannot be evaluated as a simple mono-causal intervention, or as if it was independent of its dynamic internal and external environment. Therefore, it is hardly surprising that the positive effects of an OSH MS on health and safety performance have been difficult to demonstrate in systematic reviews that do not take account of such factors[30].

The main factors for success or failure of OSH management systems

Occupational health and safety management system are a valuable approach, but their effectiveness is influenced by a range of internal and external factors. Several of these factors have already been mentioned above.

Table 2 summaries the factors critical to the functioning and usefulness of OSH management system[4][3][31].

Table 2: Factors contributing and hindering the effectiveness of OSH MS

Contributing to effective OSH MS Barriers to effective OSH MS
Managing system implemented with the intend of improving OSH Managing system introduced and supported by reasons other than OSH
Managing system customised to organisational needs Blue-print for a system imposed without modification
Investing in OSH is seen as an investment in the future of the company Investments is OSH are mainly regarded as a cost
OSH objectives are contributing to the strategic development of the organisation OSH is focussed on the control of operational problems
Strong senior management commitment OSH responsibilities delegated to lower management, or OSH staff
Developed with the support and involvement of all internal and external stakeholders of the organisation Imposed by senior management without consultation
Focus on working environment, work organisation and social innovation Focusses on control of worker behaviour
OSH is integral to management performance appraisals Limited mechanisms of accountability
Management living up to its 'messages' Management words unsupported by actions
OSH is incorporated in all jobs, tasks and processes OSH MS activities remain separated from business processes
All workers encouraged, trained and involved in OSH. Use of tacit knowledge of the workers. OSH restricted to 'technical' experts. Inadequate training and consultation of workers on OSH
A stable organisation with stable workforce Numerous reorganisations, high labour turnover, high percentage of externally contracted workers
Larger organisation, familiar with management systems and with adequate resources Small business with limited resources and unfamiliar with management system concepts[32][33]
Audits appropriately used to verify and validate OSH MS and facilitate continual improvement Inappropriately used audits that encourage 'paper based systems' and an instrumental approach to OSH MS.
Provision of adequate resources Inadequate resources

Challenges for the future development of OSH management systems

As we have described, OSH management system do not function as independent systems, but are impacted on by a range of internal and external factors. The compatibility with a changing external environment and the development of an internal context that is supportive to OSH suggests that the main challenges for the future development of occupational health and safety management system are:

  • to make OSH MS better suited to the ‘changing world of work’, where production is increasingly outsourced and risks can be easily shifted to partners in the supply chain[34], or to contingency workers[35].
  • to develop OSH MS that contribute explicitly to organisational strategy and business goals, as well as deliver OSH benefits[36]. In this respect, the growing attention to corporate social responsibility forms an opportunity to develop innovative OSH MS and OSH strategies[37].
  • to factor business ethics and organisational learning processes into the design and functioning of OSH MS. This implies additional dimensions, such as business ethics and value management[38].
  • to develop useful and practical sets of performance indicators in order to monitor and steer the development of OSH MS and OSH performance[39].


[1] Hale A.R. & Hovden J., Management and culture: the third age of safety. In A.M. Feyer & A. Williamson (eds.) Occupational Injury: risk, prevention and intervention, Taylor & Francis, London, 1998, pp. 129-66.

[2] ISO 45001:2018 Occupational health and safety management systems — Requirements with guidance for use

[3] Visser R. & Zwetsloot G.I.J.M. (ed), Arbomanagement in bedrijven (OSH Management in companies), 233 pp. Serie organisatiekwaliteit, Kluwer, Deventer, 2004.

[4] Gallagher, C., Underhill, E., & Rimmer, M., Occupational Health and Safety Management Systems: A Review of their Effectiveness in Securing Healthy and Safe Workplaces. National Occupational Health and Safety Commission, Sydney, 2001.

[5] EU OSHA – European Agency for Safety and Health at Work, The use of occupational safety and health management systems in the member states of the European Union – experiences at company level, 2002. Available at:

[6] Hasle P. & Zwetsloot, G.I.J.M., ‘Occupational Health and Safety Management Systems: issues and challenges’, editorial for the special issue on Occupational Health and Safety Management Systems, Safety Science, 49, 7, 2011, pp. 961-63,.

[7] Walters, D., (ed.), Regulating Health and Safety Management in the European Union. P.IE.-Peter Lang, Brussels, 2002.

[8] Jensen, P.L. & Jensen, J., Carrots and sticks inspection strategies in Denmark (Rep. No. Working paper 12). National Research Centre for OHS Regulation, Canberra, 2003.

[9] Health and Safety Executive (HSE), A Guide to Measuring Health and Safety Performance, HSG 65, Health and Safety Executive, UK, 2001.

[10] OHSA – Occupational Health and Safety Organisation, United States (2011). Voluntary Protection Program. Retrieved on d14 June 2011, from

[11] Zwetsloot G.I.J.M., Developments and debates on OHSM system standardisation and certification, In: K. Frick, M.Quinlan, P. Langaa Jensen & T. Wilthagen (eds.), Systematic Occupational Safety & Health Management: Perspectives on an International Development, Pergamon-Elsevier Science, Oxford, 2000, pp. 391-412.

[12] ILO - International Labour Organisation. ILO-OSH-2001 Guidance on occupational safety and health management systems, ILO, 2001. Available at:

[13] Hohnen P. & Hasle, P. ‘Making work environment auditable, a critical case study of certified occupational health and safety management systems in Denmark’, Safety Science, special issue on Occupational Health and Safety Management Systems, 49, 7, 2011, pp. 1022-29,.

[14] Frick K., Worker influence on voluntary OHS management systems – A review of its ends and means’’, Safety Science, special issue on OSH Management systems, 49, 7, 2011, pp. 974-87.

[15] WHO – World Health Organisation, Healthy Workplaces: a model for action for employers, workers, policy makers and practitioners, Geneva 2010.

[16] ISO 45003, Occupational health and safety management – Psychological health and safety at work – Guidelines for managing psychosocial risks. Available at:

[17] ISO, Management system standards. Retrieved 28 March 2022 from

[18] BSI – British Standardisation Institute. Occupational health and safety management systems - requirements, OHSAS 18001, London, 2007.

[19] Granerud L. & Rocha, R., ‘Organizational Learning and Continuous Improvement of OHS conditions in Danish certified OHSMS manufacturers’, Safety Science, special issue on Occupational Health and Safety Management Systems, 49, 7, 2011, pp. 1030–039,.

[20] IAF MD22:2019 Application of ISO/IEC 17021-1 for the Certification of Occupational Health and Safety Management Systems (OH&SMS). Available at:

[21] Zwetsloot G.I.J.M., Joint Management of Working Conditions, Environment and Quality; in Search of Synergy and Organisational Learning, doctoral thesis, NIA, Amsterdam, 1994.

[22] EU OSHA – European Agency for Safety and Health at Work, Mainstreaming OSH into business management, Bilbao, 2010. Available at:

[23] ISO, ISO survey 2020. Available at:

[24] Zwetsloot G.I.J.M., A. Hale & S. Zwanikken, ‘Regulatory risk control through mandatory occupational safety and health (OSH) certification and testing regimes (CTRs)’, Safety Science, special issue on OSH Management Systems, 49, 7, 2011, pp. 995–1006,.

[25] Zwetsloot G.I.J.M., S. Zwanikken & A. Hale. ‘Policy expectations and the use of market mechanisms for regulatory OSH certification and testing regimes’, Safety Science, special issue on OSH Management systems, 49, 7, 2011, pp. 1007–13.

[26] Blewett V. & O’Keeffe, V., ‘Weighing the pig never made it heavier: Auditing OHS, Social Auditing as Verification of Process in Australia’, Safety Science, special issue on Occupational Health and Safety Management Systems, 49, 7, 2011, pp. 1014-21.

[27] Frick, K., Jensen, P.L., Quinlan, M. & Wilthagen, T. (eds.), Systematic Occupational Health and Safety Management ‒ Perspectives on an International Development. Pergamon-Elsevier Science, Oxford, 2000

[28] Madsen, C., Kirkegaard, M., Dyreborg, J., Hasle, P., Making occupational health and safety management systems ‘work’: A realist review of the OHSAS 18001 standard, Safety Science, volume 129, 2020. Available at:

[29] Walters, D. & Frick, K., Worker Participation and the Management of Occupational Health and Safety: Reinforcing or Conflicting Strategies. In K.Frick, P. L. Jensen, M. Quinlan, & T. Wilthagen (eds.), Systematic Occupational Health and Safety Management Pergamon-Elsevier Science, Oxford, 2000, pp. 43-65.

[30] Robson, L.S., Clarke, J.A., Cullen, K., Bielecky, A., Severin, C., Bigelow, P., Irvin, E. & Culyer, A.J., ‘The effectiveness of occupational health and safety management system interventions: a systematic review’. Safety Science, 45, 3, 2007, pp. 329-53,

[31] Zwetsloot G.I.J.M. & A. van Scheppingen, Van Gezond Werk wordt iedereen beter (Healthy Work is Better for Everybody), Den Haag, 2005.

[32] Arocena, P. & Nunez, I., ’An empirical analysis of the effectiveness of occupational health and safety management systems in SMEs’, International Small Business Journal, 28, 2010, pp. 98-419.

[33] Makin, A.M. & Winder, C., ‘A new conceptual framework to improve the application of occupational health and safety management systems’. Safety Science, 46, 2008, pp. 935-48.

[34] Walters & James, ‘What motivates employers to establish preventive management arrangements within supply chains?’, Safety Science, special issue on OSH Management systems, 49, 7, 2011, pp. 988- 94.

[35] Quinlan, M., Mayhew, C. & Bohle, P., ‘The global expansion of precarious employment, work disorganization, and consequences for occupational health: Placing the debate in a comparative historical context’. International Journal of Health Services, 31, 2001, pp. 507-36.

[36] Zwetsloot, G.I.J.M., van Scheppingen, A.R., Dijkman, A., Heinrich, J. & den Besten H., ‘The organizational benefits of investing in workplace health’, International Journal of Workplace Health Management, Vol 3, 2010, pp. 143-59.

[37] EU OSHA – European Agency for Safety and Health at Work, Corporate Social Responsibility and Safety and Health at Work, Bilbao, 2004. Available at:

[38] Zwetsloot G.I.J.M.,’ From Management Systems to Corporate Social Responsibility’, Journal of Business Ethics, special issue on Corporate Social Responsibility, 44, 2003, pp. 201-7.

[39] Körper, B., Möller, K. & Zwetsloot, G.I.J.M.,’ The Occupational Safety & Health Scorecard’, Scandinavian Journal of Work, Environment and Health, 35, 6, 2009, pp. 413-20.

Further reading

EU OSHA – European Agency for Safety and Health at Work, The use of occupational safety and health management systems in the member states of the European Union – experiences at company level, 2002. Available at:

EU-OSHA – European Agency for Safety and Health at Work, Improving compliance with occupational safety and health regulations: an overarching review, 2021. Available at:

EU-OSHA – European Agency for Safety and Health at Work, EU-OSHA review of successful Occupational Safety and Health benchmarking initiatives, 2015. Available at:

EU OSHA – European Agency for Safety and Health at Work, Mainstreaming OSH into business management, Bilbao, 2010. Available at:

ILO – International Labour Organisation, OSH Management System: A tool for continual improvement, ILO, Geneva, 2011. Available from:

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Klaus Kuhl

Gerard Zwetsloot

Karla Van den Broek

Prevent, Belgium