OCI Nitrogen, one of Europe's largest fertilizer producers, is investigating the extent to which it is possible to take targeted measures at an early stage and stop the development of major hazard accident processes. An innovative model has been developed and recently explained and elaborated in a number of publications. This current paper contains a validation of the model by looking at the BP Texas City incident in 2005. The bowtie metaphor is used to visually present the BP Texas City refinery incident, showing the barrier system from different perspectives. Not only is the barrier system looked at from its trustworthiness on the day of the incident but also from the perspective of the control room operator, and from a design to current standards of best practice. The risk reductions of these different views are calculated and compared to their original design. In addition, evidence and findings from the investigations have been categorized as flaws and allocated to nine organizational factors. These flaws may affect the barrier system's quality or trustworthiness, or may act as ‘accident pathogens’ (see also Reason, 1990) creating latent, dangerous conditions. This paper sheds new light on the monitoring of accident processes and the barrier management to control them, and demonstrates that the BP Texas City refinery incident could have been foreseen using preventive barrier indicators and monitoring organizational factors.

OCI Nitrogen wants to gain knowledge of (leading) indicators regarding the process safety performance of their ammonia production process. This paper answers the question whether indicators can be derived from the barrier system status to provide information about the development and likelihood of the major accident processes in the ammonia production process. The accident processes are visualized as scenarios in bowties. This research focuses on the status of the preventive barriers on the left-hand side of the bowtie. Both the quality – expressed in reliability/availability and effectiveness – and the activation of the barrier system give an indication of the development of the accident scenarios and the likelihood of the central event. This likelihood is calculated as a loss of risk reduction compared to the original design. The calculation results in an indicator called “preventive barrier indicator”, which should initiate further action. Based on an example, it is demonstrated which actions should be taken and what their urgency is.

OCI Nitrogen seeks to gain knowledge of (leading) indicators regarding the process safety performance of their ammonia production process. The current research determines the most dangerous process equipment by calculating their effects resulting from a loss of containment using DNV GL's Phast™ dispersion model. In this paper, flammable and toxic effects from a release from the main equipment of an ammonia plant have been calculated. Such an encompassing approach, which can be carried out for an entire plant, is innovative and has never been conducted before. By using this model, it has been demonstrated that the effects arising from an event of failure are the largest in process equipment containing pressurized synthesis gas and ‘warm’ liquid ammonia, meaning the ammonia buffer tanks, ammonia product pumps, and the ammonia separator. Most importantly, this document substantiates that it is possible to rank the most hazardous process equipment of the ammonia production process based on an adverse impact on humans using the calculated effect distance as a starting point for a chance of death of at least 95%. The results from the effect calculations can be used for risk mapping of an entire chemical plant or be employed and applied in a layer of protection analysis (LOPA) to establish risk mitigation measures.

Ever since safety started to be investigated in a consistent manner, around 150 years ago, there has been a tremendous improvement, both in our understanding of accident processes, and in reduction of harm and damage caused by these occupational and major accidents. Major improvements in safety theories, models and metaphors were made after World War II, with the late 1970s till the late 1990s as the ‘golden years’. But still these major accidents occur and they will keep prompting future scientific developments in safety, as they have done in the past. Reducing the frequency of major accidents remains challenging. Improving design and automation, as starting point for safety has its limits due to the complexity of processes and the inability to foresee all safety related conflicts. The modern emphasis to assure the capacity to handle unforeseen events, such as resilience promises to deliver, will become even more important in the future. Inherent safe design on the other hand make a sensible approach when designing production processes for emerging and future technologies, like nano- and biotechnology. Also, it will remain difficult for small and medium sized enterprises to adhere to complicated laws and regulations. In addition, an increased participation of stakeholder groups makes future safety decision-making even more challenging than it already is today. Yet we foresee that there may be grounds for change in which safety rules, laws and regulations are set aside, the bureaucratic approach towards safety is stopped and the focus is on dynamic accident processes detection. Today, methods are developed to automatically assess time-dependant advancement of accident scenarios and barrier degradation. This direction will contribute substantially to a future higher level of safety in different industrial sectors and might alleviate the emphasis on bureaucracy. We end with developments in two countries where safety and safety science is emerging.

In The Netherlands, there are six large (petro)chemical clusters. Companies in these clusters are located next or close to each other. The policy of the Dutch government is to invest in these clusters, and to stimulate their growth. However, there is little scientific evidence that a cluster of (petro)chemical companies is safer than stand-alone (petro)chemical companies. This research, with an exploratory design, investigates parameters influencing safety of (petro)chemical clusters and stand-alone (petro)chemical companies. Insight into these parameters can lead to targeted initiatives (e.g. by government and companies) to improve safety in both clusters and stand-alone companies. Stimulating cooperation and sharing of knowledge is an important parameter, both in clusters and between clusters, and with non-clustered companies. Information exchange on accident scenarios between adjacent (petro)chemical companies with and without domino-designation requires extra attention. An overarching cluster body can contribute to a more safe, proactive and strategic cooperation. Furthermore, it is important that cluster policies include more than only spatial planning and external safety. Also after the establishment of clusters, companies should not be treated as individual companies, but as companies being part of a cluster, for instance when inspections are performed. Attention is needed for both domino-A nd escalation-effects, and possible domino-effects with (petro)chemical companies in clusters (just) below the Seveso-threshold. Integrated plants falling under the management of different companies require an adjusted approach to optimise safety.

Research question: What is the influence of general management trends and research into causes of accidents on safety management? Method: The literature study is limited to English and Dutch books, documents and articles in the scientific, professional, and technical literature from the period 1988–2010. Results and conclusions: Quite some developments occurred in the occupational safety domain. During the period concerned three models are developed, the Dutch Tripod Model, the Swedish Occupational Risk Unit Model (QARU), and the Dutch Occupational Risk Model (QRM), a barrier based model founded on the bowtie metaphor. These models address occupational accidents from different perspectives, and surprisingly similar factors. While terminology differs, these factors are called basic risk factors, situational, or management factors. Self-regulation of companies has been a strong stimulus for research on safety management systems and audits. Traditionally research in management related topics has not been part of safety research, and thus it has to be developed. While the quality of this type of research is rather low, a general structure of safety management systems is related to the Rhineland management concept. Such evidence is found in new management models such as the EFQM/INK and, to a lesser extent, Corporate Social Responsibility (CSR). While organisational learning, its quality and effectiveness on occupational safety is not researched in this period, research interests are focussing on other organisational aspects like safety culture and climate, including a renewed interest in human behaviour.

A Safety Research project was carried out in an ammonia plant of OCI Nitrogen, located at the Chemelot site in Geleen, The Netherlands. This research focused on the development of a method to monitor accident processes in the chemical industry mainly caused by mechanical integrity of static equipment like vessels, tanks and heat exchangers. A significant part of the mechanical integrity failure scenarios originates from material degradation and corrosion mechanisms which may develop over a relatively long-time period, possibly taking months, years or even longer. Mechanical failure scenarios from two process units have been worked out and visualized using a bowtie. The research project shows that the monitoring of early warnings can provide information about the current development of mechanical failure scenarios. In addition, early warnings can be used to initiate inspections if there is a likelihood that the mechanical failure scenario has been activated. Considering the shift from breakdown maintenance to preventive and predictive maintenance and risk-based inspection (RBI), inspections based on early warnings could also be a new step in the field of maintenance efficiency.

Objective: What is the influence of general management trends and safety research on managing safety? Method: A literature study which is limited to original English and Dutch books, documents, and articles in relevant scientific journals, for the period 1988–2010. Results and conclusions: Safety science does not yet have a unifying theory, which betrays its young age as a scientific discipline. In the period concerned, well-known theories, models and metaphors are established or re-issued, including the High Reliability Theory, the Man-Made Disasters and the corresponding Disaster Incubation Theory, and the Normal Accident Theory. The Swiss cheese metaphor takes its final form, the bowtie metaphor and the Drift into Danger model are published. All these theories, models and metaphors emphasize organisational aspects of major accidents in high-tech-high-hazard sectors. General management trends highlight the importance of external stakeholders, which are only reflected in the Drift into Danger metaphor. These developments must be considered in the context of a dynamic influence of external factors, like a decrease in government influence coinciding with strong market and technology developments, which can conflict with safety requirements for high-tech-high-hazard companies. Organisational/safety culture and risk/safety management systems take off during this period, both in terms of academic research and consultancy activities for companies. Whether these concepts will have a lasting influence on safety levels in companies is yet to be seen, given the unclear relationship with major accident processes. Research findings show that many companies suffer from sloppy management, having only a limited insight into possible disaster scenarios.