# The Impact of Lean on Occupational Safety in Organisations

José Carlos Sá, José Dinis-Carvalho, Helena Fraga, Vanda Lima, Francisco Silva, João Bastos

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José Carlos Sá, José Dinis-Carvalho, Helena Fraga, Vanda Lima, Francisco Silva, et al.. The Impact of Lean on Occupational Safety in Organisations. 8th European Lean Educator Conference (ELEC), Nov 2022, Galway, Ireland. pp.184-192, 10.1007/978-3-031-25741-4_16 . hal-04735668

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# The impact of Lean on occupational safety in organisations

José Carlos Sá<fnref n="1" />,<fnref n="2" />, José Dinis-Carvalho<fnref n="3" />, Helena Fraga<fnref n="1" />, Vanda Lima<fnref n="4" />, Francisco J. G. Silva<fnref n="2" />,<fnref n="5" />, João Bastos<fnref n="1" />

**Abstract** Occupational safety is a major concern these days because it is an important social issue promoting financial implications for organisations, employees, and society. But while occupational safety is an important concern, the top management of organizations usually prioritize waste and cost reduction. Therefore, there is a need for a technique that reduces waste and simultaneously improves occupational safety. Lean has been effective in reducing waste and costs. Some researchers have shown that Lean can also improve occupational safety. The objective of this work was to determine whether, in organizations where Lean tools were implemented, if there was an improvement in occupational safety conditions, namely in the reduction of accident rates, and to verify which Lean tools contributed the most to that improvement. A survey was conducted by sending a questionnaire to Portuguese organizations, from north to south and islands, who had potentially Lean tools implemented. In total, 189 answers have been obtained from organizations, 59 of which had Lean tools implemented, being considered valid answers for the study. Through statistical analysis of the data obtained, it was found that no organizations had worsened their safety indicators, some had maintained the same level and a reasonable number stated that their indicators had improved. Of these, the vast majority said that their accident rates had decreased by 20%, this being the figure that statistically showed the best results in terms of change.

**Keywords:** Safety, Lean Philosophy, Lean Tools, Lean Safety, Occupational safety.

<footnote n="1">¹School of Engineering, ISEP, Polytechnic of Porto, Porto, Portugal
cvs@isep.ipp.pt, 1170056@isep.ipp.pt, fgs@isep.ipp.pt, jab@isep.ipp.pt</footnote>

<footnote n="2">²Institute of Science and Innovation in Mechanical and Industrial Engineering
(INEGI), Porto, Portugal</footnote>

<footnote n="3">³Production and Systems Department - University of Minho, Guimarães, Portugal
dinis@dps.uminho.pt</footnote>

<footnote n="4">⁴CIICESI, ESTG, Polytechnic Institute of Porto, Portugal
vlima@estg.ipp.pt</footnote>

<footnote n="5">⁵Polytechnic of Porto, Porto, Portugal</footnote>
# 1 Introduction

Fatal accidents at work in Portugal, after a decrease for some years, had a substantial increase in 2018. Thus, the area of safety assumes a relevant importance in organizations.

Although safety at work is a major source of concern, top management generally prioritizes reducing waste and cutting costs. Therefore, there is a need to adopt measures that reduce waste and costs while improving safety. The Lean approach has been effective in reducing waste and costs while at the same time it can improve safety at work [1,2]. Accidents at work and occupational diseases most often happen because organisations do not comply with safety standards and do not act preventively [3]. This study aims to see how Lean tools can help organisations to identify potential occupational risk situations, and the impact they have on reducing accidents. Money and time spent on accidents and workers' compensation is classified as a waste, which is something that should be avoided based on the Lean philosophy. Lean aims to reduce the 3M's (Muda, Mura, and Muri), and safety aims to reduce accidents at work and occupational diseases, looking at these two goals they end up intersecting. This is because occupational diseases and accidents generate waste, and Lean tools have an impact on the aspects related to occupational safety.

For several authors, Lean has been frequently associated with safer, high quality, and high-commitment work environments, by sustainable human performance. For example, many Lean operating practices increase the level of workplace "transparency" (clear visibility of hazards, cleaner work environment, etc.) so that workers can identify, evaluate and suggest controls. And this helps reducing health and safety risks in the workplace. In particular, visual boards and other display artefacts are devices that make human/technology interactions easier and more effective. This means that effective and safe standards and procedures can be maintained, and continuous improvement processes can be facilitated. In this way, systems can provide information, signal deviations, control and ensure the correctness of processes, and, in turn, improve safety in the workplace [4]. This work aims to verify wether, in the Portuguese organizations where Lean tools were implemented, if there was a positive impact on the reduction of the accident rates, Incidence Rate (Ii), Frequency Rate (If), and Severity Rate (Ig).

# 2 Literature Review

## 2.1 Lean Approach

Lean designates a concept that is known to increase manufacturing effectiveness [5-6]. Toyota has been successful in Lean deployment, and this has inspired many organisations around the world to start a 'Lean journey'. The Lean concept is now discussed as relevant not only in manufacturing, but also in services and healthcare delivery [7-8]. Lean focuses on reducing the 3M's, maximizing value-adding activities from the customer's perspective. Moreover, from the customer's perspective, value is equivalent to whatever the customer is willing to pay for a provided product or service. Thus, the elimination of waste (Muda) is one of the basic concepts linked to Lean production [9]. An essential aspect of Lean philosophy is continuously striving for perfection in products that can be delivered customer-specific, on-demand, without waste of material, labor hours, and other resources (energy) in a safe working environment (physical, emotional and professional) [10]. The application of Lean principles depends on an organisation's commitment to continuously improving the value delivered to a customer [11].
Womack and Jones [12] proposed a set of principles to achieve a Lean enterprise. Companies should adopt these principles and incorporate them into their operations, sequentially. Thus, the Lean approach can be summarized in six principles: value specification, value chain identification, value stream, pull system, perfection, and respect for people [13].

## 2.2 Occupational Safety

Safety is defined as a state in which hazards and conditions leading to physical, psychological, or material harm are controlled to preserve the health and well-being of individuals and the community [14-15]. This state is not only related to the absence of intentional or unintentional injuries. It should also lead to a perception of being protected from danger [16]. Therefore, it includes two dimensions: one is objective and is assessed by measuring the number of injuries or factual behavioural and environmental parameters (e.g., traffic-related deaths recorded in a community, number of collisions at a dangerous intersection) [17]. The other is subjective and assessed according to the feeling of being out of danger. Both dimensions can sometimes influence each other positively or negatively [18]. Safety results from a complex process in which humans interact with their physical, social, cultural, technological, political, economic, and organisational environments [19]. Safety in companies plays a major role in motivating workers [20]. Any business knows that employee attrition and absenteeism can be major obstacles [16]. When a healthy and safe workplace is created, these problems are reduced in several ways. By budgeting for safety improvements and making safety part of the operating plan, trust is built. Involving employees in safety decisions - through reports, committees, guidelines, and meetings - demonstrates that their opinion matters to the employer. If top management pays attention to employees' opinions and improve their safety, this can tangibly prove that company care about their welfare [21].

## 2.3 Integration of Lean and Safety

Lean can be an opportunity to avoid professional risks as long as it is possible to approach it without changing the steps and without distorting the spirit. Today, the implementation of the Lean model is done with much more care. The implementation of a Lean approach can, and should, be accompanied by reflections in favor of health and safety at work [22-24]. The results will depend on how the Lean tools relate to the policy of prevention of risks at work. They will vary greatly from one company to another [20]. But taking this approach can also be an opportunity for prevention. Some situations allow addressing occupational health and safety issues either as part of standard performance improvement objectives or as a site-specific objective [16]. The two biggest challenges in the construction industry are low productivity and high injury rates, and they can be addressed simultaneously by combining Lean production strategies and traditional safety analysis tools. A study was conducted that integrated safety and a Lean tool, Kaizen, into the construction of modular housing [22]. The research team analysed the current process, determined, and implemented process improvements, and analysed the improved process. The changes made resulted in a 16% increase in the value added to the activities and by making these low-cost changes, safety risks were reduced or eliminated in some situations. These results support the hypothesis that productivity and safety can be improved simultaneously through combined safety and Lean tools [22].

In 2002, the largest Danish construction company conducted an experiment on the impact of implementing Lean tools on profit (level and predictability), safety, customer satisfaction, and administrative costs. This implementation was carried out in about 30 projects that the company had in progress. To confirm the impact of the Lean tools, projects that used Lean tools were compared with projects not using Lean tools.
With only a limited number of projects with Lean tools implemented, they found that customer satisfaction increased by two decimal points on a scale of 1 to 5. It had a positive impact on profit; the average profit of three projects with Lean tools implemented is approximately 25 percent higher than the average profit of projects that did not have Lean tools implemented. It was also proved that the accident rate is lower for projects with Lean implemented [25].

## 3 Methodology

The type of approach was qualitative research of basic nature, involving a bibliographic survey on the topic under study. Subsequently, as a data collection technique, the option fell on the elaboration of a questionnaire, whose questions were carefully thought out to provide an answer to the proposed problem. The questionnaire includes 13 questions with the following content:

<table><caption>**Table 1 - Questionnaire sent to companies**</caption><thead><tr><th>Questions</th></tr></thead><tbody><tr><td>1. Name of the Organization</td></tr><tr><td>2. In which department does the person responsible for completing the questionnaire work</td></tr><tr><td>3. Location of the Organization</td></tr><tr><td>4. Sector of Activity</td></tr><tr><td>5. No. of Workers in the Organization</td></tr><tr><td>6. If the Organization is safety certified</td></tr><tr><td>7. How many years ago the certification occurred (ranges: less than 1 year | between 1 and 3 | between 3 and 5 | between 5 and 10 | more than 10),</td></tr><tr><td>8. If company knows Lean tools,</td></tr><tr><td>9. Identify the Lean tools that company knows,</td></tr><tr><td>10. It the organization have any Lean tools implemented,</td></tr><tr><td>11. Identify the Lean tools implemented in the organization and how many years ago they were implemented (ranges: less than 1 year | between 1 and 3 | between 3 and 5 | between 5 and 10 | more than 10),</td></tr><tr><td>12. After the implementation of Lean tools there was an improvement in the Accident Rates (options: Worsened | No change | -20% | -40% | -60% | -80% | -100%)</td></tr><tr><td>13. Indicate up to 5 tools, which in the company's opinion contributed to the improvement of safety. Number, considering value 5 for the one that had more impact and value 1 for the one that had less impact.</td></tr></tbody></table>

## 4 Development and Results

A set of 1600 Portuguese organisations was selected, from north to south and islands, potentially with Lean tools implemented, to which the questionnaire was sent via email. Only those that had Lean tools implemented were analysed. A total of 189 organisations have responded, 59 of which had Lean tools implemented, which were considered valid responses for the study.
The data collection process took place from 7 August 2019 to 06 October 2019. All responses to the questionnaires were recorded and automatically transferred to an MS Excel® file, functions provided by the Google Forms® platform. This also helped to make the research more reliable as it provided easy traceability of the data obtained. These data were subsequently worked/coded in MS Excel® and then transferred to the SPSS® (Statistical Package for the Social Sciences) application.

The organisations that make up the sample are located essentially in the northern region and with special incidence in the metalworking sector. Concerning their size, the vast majority are medium and large sized. The sample includes 27 organisations with safety certification, 14 of which have been certified for over 10 years.

<table><caption>Table 2 - General table of impact by index</caption><thead><tr><th></th><th>Percentage of answers</th><th>Organisations</th><th>Marginal Percentage</th></tr></thead><tbody><tr><td rowspan="5">Incidence Index</td><td>No changes</td><td>36</td><td>61,00%</td></tr><tr><td>-20%</td><td>16</td><td>27,10%</td></tr><tr><td>-40%</td><td>5</td><td>8,50%</td></tr><tr><td>-60%</td><td>1</td><td>1,70%</td></tr><tr><td>-100%</td><td>1</td><td>1,70%</td></tr><tr><td rowspan="5">Frequency Index</td><td>No changes</td><td>34</td><td>57,60%</td></tr><tr><td>-20%</td><td>15</td><td>25,40%</td></tr><tr><td>-40%</td><td>8</td><td>13,60%</td></tr><tr><td>-60%</td><td>1</td><td>1,70%</td></tr><tr><td>-100%</td><td>1</td><td>1,70%</td></tr><tr><td rowspan="5">Severity Index</td><td>No changes</td><td>37</td><td>62,70%</td></tr><tr><td>-20%</td><td>12</td><td>20,30%</td></tr><tr><td>-40%</td><td>7</td><td>11,90%</td></tr><tr><td>-60%</td><td>2</td><td>3,40%</td></tr><tr><td>-100%</td><td>1</td><td>1,70%</td></tr><tr><td>Total Valid</td><td></td><td>59</td><td>100%</td></tr></tbody></table>

According to the data obtained in table 2, it was observed that there are no organizations that have worsened their rates, some have maintained the rates and a reasonable number attested that the rates suffered improvement alterations, of these, their great majority, said that the accident rates decreased 20%, making this the value that statistically presented the best results in terms of improvement. A correlation test was conducted between the Lean tools implemented and the three accident rates, which confirmed that there are statistically significant correlations between the Lean tools. But they are not correlated with the accident rates. The accident rates have a strong correlation between them, most probably, the higher the accident rate, the higher the probability of having serious accidents. It was found that there is no correlation between accident rates and the variables of activity sector, organisation size, safety certification, and years of certification.

From the descriptive statistical analysis, it was found that the implementation of Lean tools has an impact on accident rates. Most of the companies that managed to improve their accident rates were within the 20% threshold. The thresholds of improvement of accident rates between 20% and 60% has been chosen and analysed for the three rates to ascertain if there was a difference between the groups for four variables: activity sector, number of workers, safety certification, and years of certification.
The test chosen, based on the type of variables available was the Kruskal Wallis (KW). According to Pestana and Gageiro [26], the KW test is an extension of the Wilcoxon-Mann-Whitney test, which is a non-parametric test used to compare three or more populations. It is used to test the null hypothesis that all populations have equal distribution functions against the alternative hypothesis that at least two of the populations have different distribution functions. From the KW test for the incidence index, differences were found between the groups for the variable safety certification, (p = 0.04) and years of certification (p = 0.014). No significant differences were found between the groups for the variable sector of activity (p = 0.7) and the number of workers (p = 0.472). Based on these results, it was tried to confirm which group was causing the difference. Applied the KW test for the Frequency Index, it was found that there are no significant differences between the groups for the variables, activity sector (p = 0.793), the number of workers (p = 0.126), safety certification, (p = 0.551) and years of certification (p = 0.051). The KW test was applied to the Severity index, and it was verified that there is no difference between the groups for the variables: sector of activity (p = 0.947), number of workers (p = 0.223), safety certification (p = 0.153) and years of certification (p = 0.430). With the KW test for the grouping variable Index of Incidence, it was possible to verify that there are differences between groups for the variable's certification and years of certification. However, with this test, it was not possible to affirm if these differences had a certain linear pattern. Thus, it was opted for a comparison of means. For the certification variable, the average of the incidence index was calculated separately for non-certified and certified organisations, and it was found that the average value increased, which leads to the conclusion that in certified companies the impact of the implementation of Lean tools on the incidence index is statistically more significant. Next, it was analysed whether, within the group of organisations certified in safety, the variable years of certification influenced the incidence rate. This analysis was again based on the comparison of averages, in this case, the average *Ii* was calculated for each date interval. For the interval of less than one year of certification, no case was registered. The mean comparison analysis showed that there is an upward trend in *Ii* from the interval 1 to 3 years to the interval 5 to 10 years of certification. In the interval of more than 10 years, the average drops significantly. It cannot be said that the average value of *Ii* increases as the years of safety certification also increase. What can be said is that for the organisations that participated in the study, there was more impact of Lean tools in improving the incidence index in the certified organisations whose certification occurred in the interval between 5 and 10 years. Statistical analysis showed that it was possible to prove that Lean tools have positive impact on safety by reducing accident rates.

**5 Conclusion**

Safety has historically been treated as a separate function or issue which could be improved in isolation away from production. However, safety is an integral part of every production process, not an afterthought or an add-on, because safety depends on all actions, materials and people used. Work processes are inherently safe or hazardous according to the safety risks present at each step required to complete a process. Safety performance depends on the nature of the work and must be maintained and continuously improved as part of these processes [14,16]. Based on the data collected from the organisations that participated in this study and through statistical analysis, some support was obtained for the prediction that the accident rates will be improved with the implementation of Lean tools.
It was found that no organisations had worsened their rates, some had maintained their rates and a reasonable number stated that their rates had improved. Of these, the vast majority said that their accident rates had decreased by 20%, which was the value that statistically presented the best results in terms of change. The KW test was applied to the three accident rates and it was found that there were differences between groups for the variables certification (in safety) and years of certification in relation to the Incidence Index. With this test, it was not possible to affirm if these differences had a certain linear pattern. Thus, it was opted to make a comparison of means. It could not be affirmed that the *Ii* increases as the years of certification in safety also increase. What could be affirmed is that for the organisations that participated in the study, there is more impact of the Lean tools in the improvement of the incidence index in those that are certified and whose certification took place between 5 and 10 years. It was possible to demonstrate that Lean tools have a positive impact on the occupational safety of organisations, through the reduction of accident rates.

The analysis and discussion presented in this paper provide a theoretical and empir
ical rationale for the link between Lean tool implementation and improved occupational
safety outcomes.

Research funding

The work of the author Vanda Lima is supported by national funds, through the FCT— Portuguese Foundation for Science and Technology under the project UIDB/04728/2020.

References

[1] Cordeiro, P., Sá, J. C., Pata, A., Gonçalves, M., Santos, G., & Silva, F. J. G. (2020). The impact of Lean tools on safety—Case study. In Occupational and Environmental Safety and Health II, 277, 151-159.

[2] Sá, J. C., Manuel, V., Silva, F. J. G., Santos, G., Ferreira, L. P., Pereira, T., & Carvalho, M. (2021). Lean Safety-assessment of the impact of 5S and Visual Management on safety. IOP Conference Series: Materials Science and Engineering, 1193(1), 012049.

[3] Bastos, A., Sá, J., Silva, O., & Fernandes, M. C. (2014). A study on the reality of Portuguese companies about work health and safety. Occupational Safety and Hygiene II, 1, 687-691.

[4] Camuffo, A., De Stefano, F., & Paolino, C. (2017). Safety reloaded: Lean operations and high involvement work practices for sustainable workplaces. Journal of Business Ethics, 143(2), 245-259.

[5] Kim, C. S., Spahlinger, D. A., Kin, J. M., Coffey, R. J., & Billi, J. E. (2009) Implementation of Lean thinking: one health system’s journey. Joint Commission Journal on Quality and Patient Safety, 35, 8, 406–413.

[6] Womack, J. P., & Jones, D. T. (1997). Lean thinking—banish waste and create wealth in your corporation. Journal of the Operational Research Society, 48(11), 1148-1148.LNCS.

[7] Pettersen, J. (2009). Defining Lean production: Some conceptual and practical issues. The TQM Journal, 21(2), 127–142.

[8] Antas Aguiar, J., Telhada, J., Sameiro Carvalho, M., & Sá, J. C. (2023). Value Measurement in Health Care Delivery Process for a Paediatric Hospital in Guinea-Bissau. In International Conference Innovation in Engineering, 186-196. Springer, Cham.
[9] Arlbjorn, J., & Freytag, P. (2013). Evidence of Lean: A review of international peer-reviewed journal articles. European Business Review, 25(2), 174-203.

[10] Fullerton, R., & Wempe, W. (2009). Lean manufacturing. International Journal of Operations and Production Management, 29, 214-240.

[11] Bartels, N. (2005). Lean in the most generic sense. Manufacturing Business Technology, 23, 32-36.

[12] Womack, J. 12P., & Jones, D. T. (1996). Lean Thinking, Simon and Schuster. New York.

[13] Shah, R., & Ward, P.T. (2007). Defining and developing measures of Lean production. Journ. Oper. Manag., 25, 785-805.

[14] Koskela, L. (1992). Application of the new production philosophy to construction (Vol. 72). Stanford, CA: Stanford university.

[15] Maurice, P., Lavoie, M., Chapdelaine, A., & Bélanger-Bonneau, H. (1997). Safety and safety promotion: Conceptual and operational aspects. Chronic Dis Canada, 18(4), 179-186.

[16] Morgado, L., Silva, F. J. G., Fonseca, L. M. (2019). Mapping Occupational Health and Safety Management Systems in Portugal: outlook for ISO 45001:2018 adoption. Procedia Manufacturing, 38, 755-764.

[17] Cooper, M. D. (2000). Towards a model of safety culture. Safety Science, 36, 111-136.

[18] Baram, M., & Schoebel, M. (2007). Safety culture and behavioral change at the workplace. Safety Science, 45, 631-636.

[19] Hudson, P. (2007). Implementing a safety culture in a major multi-national. Safety Science, 45, 697-722.

[20] Brito, M. Vale, M., Leão, J., Ferreira, L. P., Silva, F. J. G., Gonçalves, M. A. (2020). Lean and Ergonomics decision support tool assessment in a plastic packaging company. Procedia Manufacturing, 51, 613-619.

[21] Reason, J. (1998). Managing the risks of organizational accidents. Aldershot: Ashgate.

[22] Ikuma, L. H., Nahmens, I., & James, J. (2010). Use of safety and Lean integrated kaizen to improve performance in modular homebuilding. Journal of construction engineering and management, 137(7), 551-560.

[23] Arezes, P. M., Dinis-Carvalho, J., & Alves, A. C. (2015). Workplace ergonomics in Lean production environments: A literature review. Work, 52(1), 57-70.

[24] Carter, B., Danford, A., Howcroft, D., Richardson, H., Smith, A., & Taylor, P. (2013). 'Stressed out of my box': employee experience of Lean working and occupational ill-health in clerical work in the UK public sector. Work, employment and society, 27(5), 747-767.

[25] Thomassen, M. A., Sander, D., Barnes, K. A., & Nielsen, A. (2003, July). Experience and results from implementing Lean construction in a large Danish contracting firm. In Proceedings of 11th Annual Conference on Lean Construction (pp. 644-655).

[26] Pestana, M. H., & Gageiro, J. N. (2008). Análise de dados para ciências sociais: a complementaridade do SPSS.