Systems-Theoretic Accident Model Research Articles

Risk assessment methods for process safety, process security and resilience in the chemical process industry: A thorough literature review

This paper presents a systematic literature review of risk assessment methods in the chemical process industry (CPI), focusing on process safety, process security, and resilience. We analyzed peer-reviewed articles from 2000 to 2022 using the PRISMA methodology and identified twelve predominant methods. Our findings reveal a shift towards dynamic, systemic-based assessments like the Functional Resonance Analysis Method (FRAM) and System-Theoretic Accident Model and Processes (STAMP). These methods are particularly effective at capturing the complexities of sociotechnical systems in the CPI. However, a significant observation from our review is the limited emphasis on the resilience paradigm within many existing methods when addressing both process safety and process security risks, which is crucial for preventing and recovering from disruptions. Given the evolving challenges in system safety and security threats, there is an urgent need for holistic methods that integrate process safety, process security, and resilience. Our review highlights the opportunity for further research to better prepare the industry for future challenges, ensuring safer, more secure, reliable, and resilient operations.

Mechanism and early warning of coal mine rockburst accident based on SD-STAMP-DEMATEL

As coal mines shift from shallow to deeper excavation, the number of mines facing the risk of rock burst disasters is gradually increasing. Rockburst, with their characteristics of vibration, suddenness, complexity, and unpredictability, make it increasingly difficult to prevent and control these disasters. Therefore, the challenges of preventing and controlling rock burst disasters are becoming more and more severe. This paper, based on the system-theoretic accident model and processes (STAMP) theory, extracts the causal factors affecting coal mine rock burst accidents. Using the interpretative structural modeling (ISM) and decision-making trial and evaluation laboratory (DEMATEL) method, the accident-causing factors are quantitatively assigned. By constructing model equations and drawing causal loop diagrams and stock-flow diagrams, the event is dynamically simulated and early warnings are issued. The results show that the control defects leading to the accident are analyzed from the perspectives of the government level, management level, grassroots level, physical layer, and the dynamic process of the accident. In the short term, safety investment in grassroots operations is the most effective control. In the long run, the most effective measure is for the management level to strengthen its supervisory work. By changing the input ratios of various variables, it can be seen that different variables in the system dynamics (SD) model have different impacts on coal mine rock burst accidents. It is necessary to continuously strengthen the implementation of the safety responsibility system, improve the work efficiency of the government and management level, and enhance the timeliness of emergency decision-making.

Safety analysis of Civil aviation Flight and UAV Operation based on STAMP/STPA

In order to prevent the occurrence of dangerous approaches or accidents in the low-altitude UAV conflict resolution process, the security problem in the process was transformed into the control problem, and a conflict resolution security analysis method for low altitude UAV based on STAMP/STPA was proposed. Firstly, based on STAMP (System Theoretic Accident Modeling and Processes), the security control structure in the conflict resolution system was constructed. Then STPA (Systems Theoretic Process Analysis) was used to determine system-level accidents and hazards based on the context information of system operation, identify the unsafe control behaviors in the process of conflict resolution, and analyze the key causes of unsafe control behaviors.

A stakeholder analysis of the road transport system in Tanzania using a STAMP control structure

The way the road transport system is developed in a country affects safety. This study aims to identify the roles and relationships of road transport stakeholders and to explore the understanding of control and feedback mechanisms and associated gaps influencing road safety. A System-Theoretic Accident Model and Processes (STAMP) model was applied to document and interview data (n = 30). Participants emphasised the hindrance of overlapping mandates among stakeholders on the road transport system’s operations and underlined the roles of coalitions for road safety as system enablers. Further, the withdrawal of some controls by international agencies can increase system vulnerability. Most importantly, critical control and feedback gaps were shown to increase risks for safety within the road transport system. The findings underscore the complexity of the road transport system and add to the discussion on a system’s approach to road safety. Practitioner summary: Using a STAMP methodology, we extensively studied the road transport system in Tanzania. Road transport stakeholders were identified through the review of documents, interviews were conducted, and the main findings were discussed. Control and feedback mechanisms and associated gaps were critically presented, recommendations were proposed, and policy implications were suggested.

Safety analysis of catapult takeoff of carrier-based aircraft using System-Theoretic Process Analysis method

Catapult takeoff has become the main way for carrier-based aircraft to take off. However, as a complex process of multi-system coupling and multi-control actions link, it is an important task to ensure the safety of catapult takeoff. Therefore, this paper adopts the System-Theoretic Process Analysis (STPA) and establishes a model of catapult takeoff using the Systems Theoretic Accident Model and Process(STAMP) model. To carry out safety analysis, identify unsafe control actions and extract the causes of unsafe behavior, simulation analysis is also carried out for typical unsafe actions. The results show that using STPA to make safety analysis, combined with simulation, can comprehensively analyze and evaluate the safety of catapult takeoff, which helps identify the risk before the flight test and reduce the flight test risk.

A STAMP-Game model for accident analysis in oil and gas industry

Accidents in engineered systems are usually generated by complex socio-technical factors. It is beneficial to investigate the increasing complexity and coupling of these factors from the perspective of system safety. Based on system and control theories, System-Theoretic Accident Model and Processes (STAMP) is a widely recognized approach for accident analysis. In this paper, we propose a STAMP-Game model to analyze accidents in oil and gas storage and transportation systems. Stakeholders in accident analysis by STAMP can be regarded as players of a game. Game theory can, thus, be adopted in accident analysis to depict the competition and cooperation between stakeholders. Subsequently, we established a game model to study the strategies of both supervisory and supervised entities. The obtained results demonstrate that the proposed game model allows for identifying the effectiveness deficiency of the supervisory entity, and the safety and protection altitudes of the supervised entity. The STAMP-Game model can generate quantitative parameters for supporting the behavior and strategy selections of the supervisory and supervised entities. The quantitative data obtained can be used to guide the safety improvement, to reduce the costs of safety regulation violation and accident risk.

Dynamic risk assessment of chemical process systems using the System-Theoretic accident model and process approach (STAMP) in combination with cascading failure propagation model (CFPM)

To maintain continuous production, chemical plant operators may ignore faults or handle faults online rather than shutting down process systems. However, interaction and interdependence links between components in a digitalized process system are substantial. Thus, faults will be propagated to downstream nodes, potentially leading to risk accumulation and major accidents. However, limited attention has been paid to this type of risk. To model the risk accumulation process, a dynamic risk assessment method is proposed by integrating the system-theoretic accident model and process approach (STAMP) and the cascading failure propagation model (CFPM). Firstly, STAMP is used to model and analyze the system safety of a process system. Two CFPMs are then proposed to measure risk accumulation under two different engineering situations. The proposed method is applied to the Chevron Richmond refinery crude unit and its associated upstream process. The results show that the proposed approach can effectively quantify the process of risk accumulation. This method can generate a real-time dynamic risk profile to support auxiliary decision-making.

A hybrid STAMP-fuzzy DEMATEL-ISM approach for analyzing the factors influencing building collapse accidents in China.

To explore the factors influencing recent construction collapse accidents, this study utilizes a sample of 355 reports on building collapse accidents from 2012 to 2022. The investigation employs the systems-theoretic accident modeling and processes (STAMP) model to retrieve 22 key causal factors of accidents from the physical, operational, managerial, and supervisory layers. Subsequently, an improved decision-making trial and evaluation laboratory (DEMATEL)-interpretive structural modeling (ISM) method is used to analyze the relationships and strengths of these influencing factors, providing a comprehensive understanding of the logical connections between the causes of building collapse accidents. The results indicate that the deep-rooted causes of building collapse accidents are primarily lax safety management at the enterprise level and the exchange of interests at the government regulatory level, which in turn affect workers at the operational level and the physical aspects of accidents on-site. Furthermore, integrating the STAMP model and the triangular fuzzy DEMATEL-ISM model overcomes the limitations of the traditional STAMP model, allowing for a more focused identification of key factors.

The hybrid systems method integrating STAMP and HFACS for the causal analysis of the road traffic accident

The role of traditional analysis methods in improving complex socio-technical system safety has reached a ceiling, and thus systems theory has been utilised to support the investigations and countermeasures for road traffic accidents. As two widely applied systems accident analysis models, STAMP (systems theoretic accident model and process) and HFACS (human factors analysis and classification system) have their own advantages in accident analysis and safety improvement. Therefore, this study develops a new hybrid systems method integrating STAMP and HFACS for road traffic accident (SH-RTA), which can adopt HFACS to enhance the identification and analysis ability of STAMP for human factors and employ control concepts and elements of STAMP to cement the characteristic of HFACS. To illustrate the applicability of the hybrid method, a case study of ‘9·22’ major road traffic accident in China is thoroughly analysed. Finally, preventive countermeasures and suggestions are presented. Practitioner Summary: This paper proposes a new hybrid systems method integrating STAMP and HFACS for road traffic accident. The new method reveals dysfunctional interactions within the parallel level and across levels, and identifies additional human and organisational factors. The recommendations for preventing road traffic accident are provided from higher levels of system.

Improving patient safety governance andsystems through learning from successes andfailures: qualitative surveys andinterviews with international experts.

Patient harm is a leading cause of global disease burden with considerable morbidity, mortality, and economic impacts for individuals, families, and wider society. Large bodies of evidence exist for strategies to improve safety and reduce harm. However, it is not clear which patient safety issues are being addressed globally, and which factors are the most (or least) important contributors to patient safety improvements. We aimed to explore the perspectives of international patient safety experts to identify: (1) the nature and range of patient safety issues being addressed, and (2) aspects of patient safety governance and systems that are perceived to provide value (or not) in improving patient outcomes. English-speaking Fellows and Experts of the International Society for Quality in Healthcare participated in a web-based survey and in-depth semistructured interview, discussing their experience in implementing interventions to improve patient safety. Data collection focused on understanding the elements of patient safety governance that influence outcomes. Demographic survey data were analysed descriptively. Qualitative data were coded, analysed thematically (inductive approach), and mapped deductively to the System-Theoretic Accident Model and Processes framework. Findings are presented as themes and a patient safety governance model. The study was approved by the University of South Australia Human Research Ethics Committee. Twenty-seven experts (59% female) participated. Most hailed from Africa (n = 6, 22%), Australasia, and the Middle East (n = 5, 19% each). The majority were employed in hospital settings (n = 23, 85%), and reported blended experience across healthcare improvement (89%), accreditation (76%), organizational operations (64%), and policy (60%). The number and range of patient safety issues within our sample varied widely with 14 topics being addressed. Thematically, 532 textual segments were grouped into 90 codes (n = 44 barriers, n = 46 facilitators) and used to identify and arrange key patient safety governance actors and factors as a 'system' within the System-Theoretic Accident Model and Processes framework. Four themes for improved patient safety governance were identified: (1) 'safety culture' in healthcare organizations, (2) 'policies and procedures' to investigate, implement, and demonstrate impact from patient safety initiatives, (3) 'supporting staff' to upskill and share learnings, and (4) 'patient engagement, experiences, and expectations'. For sustainable patient safety governance, experts highlighted the importance of safety culture in healthcare organizations, national patient safety policies and regulatory standards, continuing education for staff, and meaningful patient engagement approaches. Our proposed 'patient safety governance model' provides policymakers and researchers with a framework to develop data-driven patient safety policy.

A preliminary study on the barriers and facilitators to improving the health, safety, and well-being of aging heavy vehicle drivers

Introduction. Managers from road freight transportation organizations were interviewed on barriers and facilitators to implementation of occupational health, safety, and well-being interventions for aging heavy vehicle drivers. As aging drivers are more likely to be seriously injured or die in a work-related incident than younger drivers, it is important to recognize strengths and weaknesses throughout the system to identify intervention that addresses their specific needs. Method: A Systems Theoretic Accident Model and Processes (STAMP) control structure was constructed to chart the controllers, controls, and feedback channels in the system to identify gaps in health, safety, and well-being intervention in the system. The STAMP control structure also charted the barriers and facilitators within levels across the system. Eleven managers were recruited into the study representing a range of road freight transportation organizations throughout Australia. Results: Interview data revealed that barriers and facilitators existed at most levels of the system. Facilitators included advice from external agencies, support from upper management, modern technology, and regular social communication with drivers. Barriers were a lack of guidance on aging issues, operational conflicts with health and safety objectives, and the drivers’ fear of disclosing health information associated with their driving role. In regards to formalized intervention in place to support aging heavy vehicle drivers, the system is reliant on fitness to drive medical assessments based on age and jurisdiction. Conclusions: As there was generally a lack of senior direction cited from the upper levels of the system on aging issues, there was much variation across the study on how aging risks are managed in the workplace for heavy vehicle drivers. Practical Applications: This study recommends that managers across the road freight transportation industry receive formalized aging-awareness health and safety training in how to manage work-related driving hazards for aging heavy vehicle drivers.

Analysis of Energy Laboratory Safety Management in China Based on the System-Theoretic Accident Model and Processes/System Theoretic Process Analysis STAMP/STPA Model

Laboratory safety in colleges and universities has received wider attention as a critical annual inspection by the Ministry of Education. The laboratory environment is complex and diverse, with many hazard factors. To effectively prevent the occurrence of laboratory emergencies in universities, the STAMP/STPA model is used to analyze the safety of energy laboratory safety management in a resource-based university. Between 2021 and 2022, we carried out laboratory safety inspection and field observation for a mining resource university in China, and identified 16 unsafe control actions in the field of energy laboratory safety management in the university, and identified ten critical causal factors leading to unsafe control actions. Combining the actual situation of the mining resource university, the short-term countermeasures and long-term countermeasures to improve laboratory safety management are proposed to guarantee the university’s laboratory safety management. Moreover, the research results have suggestions for the construction and development of laboratory safety management at similar universities.

A System-Theoretic Fuzzy Analysis (STheFA) for systemic safety assessment

The interactions among distinct systems and components have attracted more attention recently due to safety concerns. Indeed, modern industrial plants could be regarded as complex socio-technical systems influenced by human, social, and organizational aspects. To model this level of complexity, System Theory (ST) and related frameworks, such as System-Theoretic Accident Model and Processes (STAMP) have been introduced. Despite their strengths and abilities, ST techniques are mainly qualitative and provide much information, eventually complicated to analyse and summarize. Fuzzy Set Theory (FST) and expert elicitation could be employed to cope with the former challenges. However, addressing the uncertainty arising from differences in expert opinions is necessary. To this end, this paper aims to develop a framework to conduct system safety assessments based on the integration of STAMP and FST. In this context, an improved version of the Similarity Aggregation Method is adopted to aggregate judgments. To demonstrate the application of the approach, a Natural Gas Regulating and Metering Station (NGRMS) is considered as the case study. The results show that the methodology is able to provide quantitative information by associating a level of criticality with each control action. Accordingly, managers could exploit the framework to identify priorities for directing efforts.

Managing the risks associated with technological disruption in the road transport system: a control structure modelling approach

Road transport is experiencing disruptive change from new first-of-a-kind technologies. While such technologies offer safety and operational benefits, they also pose new risks. It is critical to proactively identify risks during the design, development and testing of new technologies. The Systems Theoretic Accident Model and Processes (STAMP) method analyses the dynamic structure in place to manage safety risks. This study applied STAMP to develop a control structure model for emerging technologies in the Australian road transport system and identified control gaps. The control structure shows the actors responsible for managing risks associated with first-of-a-kind technologies and the existing control and feedback mechanisms. Gaps identified related to controls (e.g. legislation) and feedback mechanisms (e.g. monitoring for behavioural adaptation). The study provides an example of how STAMP can be used to identify control structure gaps requiring attention to support the safe introduction of new technologies.

A system theory (STAMP) based quantitative accident analysis model for complex engineering systems

This paper is aimed to propose a hybrid accident analysis framework for complex engineering systems based on methods of the systems theoretic accident model and process (STAMP), failure modes and effects analysis (FMEA), and analytic hierarchy process (AHP). Within the scope of the proposed model, initially, an accident is qualitatively analyzed by identifying safety constraints, constructing a hierarchical control process, and specifying links between unsafe activities. As a second step, failure modes, their causes, and their consequences are determined. Lastly, the risk scores of each failure mode are calculated by analysis of obtained expert judgments. In this step, as different from the conventional FMEA, results are calculated based on the weight scores that are found according to the AHP approach of each accident factor. For the demonstration stage, a real case study is performed to present the effectiveness of the strategy. It is observed that the proposed approach allows analyzing the accident more specifically by defining each relationship between factors and root causes corresponding to the accident and prioritizing them based on the weights, which are assigned according to the accident's nature. In addition, it may be adapted for different complex engineering systems as well as it is a suitable and useful model for the accident analysis associated with smart ship concepts.

An integrated resilience assessment methodology for emergency response systems based on multi-stage STAMP and dynamic Bayesian networks

The interactions of external disruptions and technical-human-organizational factors in emergency operations are usually observed. Resilience assessment of emergency systems can improve emergency response capability and system functional recovery. The increasing complexity and coupling of factors in emergency response systems need to be investigated from a system resilience perspective. In this paper, we propose to integrate a multi-stage System-Theoretic Accident Model and Processes (STAMP) with a dynamic Bayesian network (DBN) for the resilience assessment of emergency response systems. In the proposed methodology, emergency response systems are viewed as multi-step emergency operations for STAMP to analyze the hierarchical control and feedback structures. The output of multi-stage STAMP in controllers, actuators, sensors, and controlled processes is applied to develop a DBN for resilience assessment. For known external shocks (e.g., natural disasters), the effects of external shocks on the system are decomposed into subsystems or components. System degradation and recovery models are established. Regarding unknown external disruption (e.g., unforeseen failure modes), degeneration and recovery are temporally integrated into the analysis of system functionality. System performance is evaluated through the combination of socio-technical factors and external disasters. Eventually, the resilience of emergency response systems is obtained from the performance curves. The results demonstrate that the proposed model can evaluate system resilience after the system suffers from external disasters.

From Anti-doping-I to Anti-doping-II: Toward a paradigm shift for doping prevention in sport.

Doping remains an intractable issue in sport and occurs in a complex and dynamic environment comprising interactions between individual, situational, and environmental factors. Anti-doping efforts have previously predominantly focused on athlete behaviours and sophisticated detection methods, however, doping issues remain. As such, there is merit in exploring an alternative approach. The aim of this study was to apply a systems thinking approach to model the current anti-doping system for four football codes in Australia, using the Systems Theoretic Accident Model and Processes (STAMP). The STAMP control structure was developed and validated by eighteen subject matter experts across a five-phase validation process. Within the developed model, education was identified as a prominent approach anti-doping authorities use to combat doping. Further, the model suggests that a majority of existing controls are reactive, and hence that there is potential to employ leading indicators to proactively prevent doping and that new incident reporting systems could be developed to capture such information. It is our contention that anti-doping research and practice should consider a shift away from the current reactive and reductionist approach of detection and enforcement to a proactive and systemic approach focused on leading indicators. This will provide anti-doping agencies a new lens to look at doping in sport.

Assessment of the Explosion Accident Risk in Non-Coal Mining by Hasse Diagram Technique

The aim of is paper is to address the problem of identifying critical factors in the analysis of non-coal mine explosion accidents as well as to improve the rationality and accuracy of the risk analysis results. Hence, we developed a risk identification method for non-coal mine explosion accidents, combining the Systems-Theoretic Accident Model and Process (STAMP) and the Rank-order Centroid (ROC) method based on the Poset decision-making theory. The proposed method was applied to identify risk in engineering cases. Findings showed that four main dangerous events (out of twelve identified ones) were the primary culprits of related accidents, which were the events “Blasters without licenses and illegal operation” at the basic level, the event of “the confusion about the safety management system of non-coal mine companies” at the control level, and the event of “the failure about the emergency management departments” and “public security departments” at the supervision level. The approximate values of the average rank of the four events are 11.56, 10.4, 4.33, 4.33. The results of risk identification of non-coal mine explosion accidents based on Poset were consistent with the results obtained by the method used in the case study. This study extends the methods for identifying risks of non-coal mine explosion accidents and facilitates the formulation of effective preventive measures.

A proposed validation framework for the system theoretic process analysis (STPA) technique

Validation is a prominent challenge in the domain of risk management in general, and hazard analysis in particular. Practitioners have highlighted a lack of clear guidance on how to perform validation of hazard analyses, who should be involved, and when to stop the validation process. Aiming to contribute to addressing this issue, this study proposes a validation framework for the System Theoretic Process Analysis (STPA) technique, based on foundational concepts in risk analysis and prior theoretical work on validation in related disciplines. STPA, which is a hazard analysis technique based on System-Theoretic Accident Model and Processes (STAMP) accident causality model, is selected due to its increasing popularity in different industries, and because no validation frameworks have yet been proposed for this technique. The proposed STPA validation framework aims to support a systematic assessment of the analysis's comprehensiveness, accuracy, and credibility. It consists of a set of theory-based concepts that are elaborated as guide questions, each focusing on different aspects of STPA. The framework employs a formative approach, i.e., it aims to help stakeholders systematically reason about the analysis and advise on improvements or further elaboration. To develop this framework, theoretical validation concepts in the pertinent literature in risk science, social science, and operations research, system dynamics, and simulation modeling disciplines have been used. It is recognized that the proposed framework should be further tested to confirm its practical usefulness, and it should be investigated whether it indeed improves the hazard analysis in terms of the envisioned functions.

Insights in the safety analysis of an early microreactor design

A safety analysis of a transportable, plug-and-play, heat-pipe-cooled microreactor – or Nuclear Battery (NB)– designed at MIT is presented. The considered design is a semi-autonomous 5 MW (thermal) high-temperature heat-pipe-cooled, yttrium-hydride moderated NB envisioned to be a transportable, flexible, affordable, and distributed low-carbon energy source.The analysis makes use of a recently proposed methodology that integrates i) System-Theoretic Accident Model and Processes (STAMP) to guide a qualitative exploration of the NB threats and hazards, ii) Modeling and Simulation (M&S) to investigate the NB dynamic behavior during accident scenarios, and iii) Goal-Tree Success-Tree Master Logic Diagram (GTST-MLD) to assess risk quantitatively. The methodology has been shown to provide systematic risk insights without the need to rely on prior operating experience, and enables a dynamic evaluation of the risk profile. Moreover, it identifies unknown threats and hazards relevant to the novel microreactor design and explores the related accident scenarios. The key findings of the safety analysis performed on the nuclear microreactor considered are the identification of vulnerabilities related to the use of yttrium hydride as the moderator, the assessment of threats and accident scenarios associated with the loss of sodium from the heat pipes, and, for such scenarios, the quantification of the grace time, i.e., the period during which human operators can intervene to avoid unacceptable consequences.