Dilution with air to minimise consequences of toxic/flammable gas releases

Dilution has long been considered a solution to many problems of toxic/flammable material releases. It implies diluting to a concentration that is below physiologically dangerous levels for a toxic substance (generally below TLV), or to a level below LFL for a flammable material release, ensuring that the process adopted for dilution does not itself enhance the risks.

In this paper, we discuss the dilution of a gaseous release by deliberate and cautious mixing with air to reduce its concentration to a harmless level. The idea bears its origin to the Bhopal Gas Tragedy where some families saved themselves by turning the ceiling fans on when MIC reached their bedrooms at the dead of very cold night on December 2–3, 1984. The air pushed in by the fans diluted the MIC to below the harm level.

Some of the advantages of using air dilution are: no cost of air, no air storage needed, no need to treat the air after use as in case of water curtains; required equipment, its maintenance and staff training in its use are very likely to cost less than in other ways of handling a release.

Air dilution may not be feasible in all cases, such as gaseous release within a congested equipment layout, release that forms a liquid pool, etc. The method needs to be evaluated for each case.     

The role of local communities in chemical accident prevention and preparedness

Since the adoption of community right-to-know programs in the US there has been an increase in the number of groups known as local emergency planning committees. These committees have matured in focus over the intervening years since the Bhopal incident and even more so since the events of September 11, 2001. There is a strong recognition that local communities working very closely with chemical handling facilities in their areas can directly and meaningfully reduce the threat of a chemical release incident, regardless of cause. Likewise, through similar means they can better prepare themselves to respond should an incident occur. Especially as regards modern concepts of process chemical safety and facility security, local communities can be of great assistance to smaller facilities that do not otherwise necessarily have the resources to accomplish these tasks. As the vulnerabilities of a facility to accident or intentional act, the impacts of these events and the ability of communities to react are all a function of local conditions, it is clear that these local efforts can be more meaningful than large-scale national efforts. While national legislation is certainly helpful to the process of bringing people together, it is the local relationships that produce results.     

The unfolding of Bhopal disaster

As an employee of Union Carbide India at the Bhopal plant, I know how the disaster happened. The merciless cost-cutting severely affecting materials of construction, maintenance, training, manpower and morale resulted in the disaster that was waiting to happen. Significant differences between the West Virginia, USA plant and the Bhopal, India plant show the callous disregard of the corporation for the people of the developing countries. The narrative below, if given a proper thought by the management and governments, should help in significantly reducing industrial accidents.     

Bhopal gas tragedy: scientific challenges and lessons for future

Some of the challenges of BGT were answered by two multi-disciplinary projects of the ICMR on Pathology and Toxicology and Pathophysiology. Unlike other chemical disasters, the aerosol inhaled by the Bhopal victims contained a mixture of MIC and its trimers and dimers, as well as aqueous and thermal decomposition products, including HCN. A coordinated GC–MS study of the blood and autopsy tissues and chemicals in the Tank residue confirmed their role.

Autopsy studies revealed the pathological changes in the acute, sub-acute and chronic phases progressive changes of pulmonary edema and bronchiolitis, followed by chronic pulmonary fibrosis. Cerebral edema resulted in ‘acute histotoxic anoxia’. Intensive experimental studies with the help of newer tools of molecular biology might throw more light on the underlying mechanisms and newer therapeutic approaches.

The initial finding of cherry-red discoloration of lungs led to a suspicion of cyanide toxicity. Eventually, elevated blood and tissue cyanide levels confirmed the prompt therapeutic response to NaTS and accompanying increase of urinary NaSCN excretion. However, periodic clinical recurrences and relapses pointing towards ‘chronic cyanide toxicity’ remained enigmatic.

Specific changes the 2–3 DPG levels and Blood Gases were explained on the basis of N-carbamoylation of end-terminal valine residues of Hb. Soon, several other end-terminal -amino groups of tissue proteins were also found to be N-carbamoylated. Had the attempts at demonstrate S-carbamoylation of glutathione and other SH radicals of tissue enzymes like rhodanese succeeded, perhaps the underlying mechanism of chronic cyanide toxicity due to MIC might have been resolved.

Based on the practical lessons learnt in Bhopal, an attempt will be made to present the salient pathological and toxicological findings, followed by a brief outline of the principles of planned laboratory management for alleviation of human suffering from future chemical disasters.     

Lessons after Bhopal: CSB a catalyst for change

The Bhopal tragedy was a defining moment in the history of the chemical industry. On December 3, 1984, a runaway reaction within a methyl isocyanate storage tank at the Union Carbide India Limited pesticide plant released a toxic gas cloud that killed thousands and injured hundreds of thousands. After Bhopal, industrial chemical plants became a major public concern. Both the public and the chemical industry realized the necessity of improving chemical process safety.

Bhopal served as a wake-up call. To prevent the same event from occurring in the United States, many legislative and industrial changes were invoked—one of which was formation of the U.S. Chemical Safety and Hazard Investigation Board (CSB). The ultimate goal of CSB is to use the lessons learned and recommendations from its investigations to achieve positive change within the chemical industry—preventing incidents and saving lives.

Although it seems clear that the lessons learned at Bhopal have improved chemical plant safety, CSB investigations indicate that the systemic problems identified at Bhopal remain the underlying causes of many incidents. These include:

• Lack of awareness of reactive hazards.

• Lack of management of change.

• Inadequate plant design and maintenance.

• Ineffective employee training.

• Ineffective emergency preparedness and community notification.

• Lack of root cause incident investigations and communication of lessons learned.

The aim of this paper is to present common themes from recent cases investigated by CSB and to discuss how these issues might be best addressed in the future.

This paper has not been independently approved by the Board and is published for general informational purposes only. Any material in the paper that did not originate in a Board-approved report is solely the responsibility of the authors and does not represent an official finding, conclusion, or position of the Board.     

Literary and economic impact of the Bhopal gas tragedy

The 1984 Bhopal disaster is widely regarded as a watershed event in the field of process-safety and has been largely responsible for a paradigm shift in the outlook of both industry and the public towards risk management within the processing industries. The Bhopal disaster has led to increased regulations and awareness for process-safety related activities across the globe. This paper reports the effect of the infamous Bhopal incident on the research community and examines the performance of manufacturing industries following the disaster.

For this paper, databases of scientific publications were used to investigate research trends in the safety area following the 1984 Bhopal disaster. Our analysis focuses on prominent safety-related research fields that have emerged following the gas tragedy as well as economic indicators of the processing industries. The study reveals that the process industry has consistently progressed over the years, in spite of added regulations and a worsened public image following the Bhopal disaster, and promises to be a stable economy in the future.     

An evaluation of risk assessment framework for industrial accidents in India

Due to rapid industrialization, with high population density and constraints of land, it is expected that level of risks arising from the hazardous industries will increase in India in the coming decades. However, 30 years after the Bhopal accident (1984), except a few discrete regulations, there is as yet no integrated system for assessing and managing risks arising out of these hazardous industries in India. The gravity of aspects related to the management of industrial risk still remains crucially important. In particular, there is no standard guideline on risk analysis methodology, acceptability or tolerability criteria, nor is there an accident database or a risk reduction strategy for the areas where risk levels are already high. On top of this, there are technical and legislative gaps in the institutional framework to implement any of the above mentioned issues. With the backdrop of the Bhopal gas tragedy, the objective of this paper is therefore to evaluate the effectiveness of a comprehensive risk assessment framework for the emerging economy of India, in order to control and/or to reduce the risk level that exists. In this context, regulations and policies pertaining to industrial risk assessment were reviewed.     

Export inherent safety NOT risk

The author presents a personal view that production of bulk chemicals and the attendant risks are being transferred from developed to developing nations. Some evidence is presented on the transfer of production. The transferred risk is increased because of the larger scale plants that are now built in locales that are less able to cope with the increased hazards. Bhopal was an example of an inherently unsafe plant, with major hazards that could have been avoided or drastically reduced by design. It behoves the industry to adopt the inherently safer philosophy and practice in the new plants that it builds, in order to minimise the opportunity for another accident like Bhopal and the threat to our industry that such an accident would pose.     

An evaluation of Manutention training in preventing back strain and resultant injuries in nurses

As the number of manual handling injuries in carers and nurses continues to be very high, the problem of how to prevent injury has not been solved. Despite the obvious need for optimum working environments, the literature does not really support that an ergonomics or systems approach solves the injury problem. Similarly, the evidence for training as a preventive strategy is equivocal, although clearly people handling requires trained handlers for both their own and the patient's safety. This research aimed to evaluate the outcomes of training in a method of manual handling of people, Dotte's Manutention method, which claims to decrease back strain and effort in carers. The study evaluated handling techniques and injury outcomes of a group of nurses in a nursing home trained in this method, using two other homes as comparisons. The study hypothesized that training in the Manutention method would decrease back strain and resultant back injuries in nurses working in geriatric care. The results showed a clear pattern of declining incidence of nurses' back pain for the nurses trained in Manutention and increasing incidence in the other two homes. These findings approached significance with a probability of < 0.1. Of those respondents who indicated a decrease in pain during the twelve month research period, all attributed it to their training. Ninety four percent of respondents who received training agreed it made their manual handling job easier. The observation method used was not sensitive enough to evaluate the multiple movements involved in a patient transfer. A supplementary controlled study was performed using videotaping and the Ovako Working Assessment System (OWAS). Manutention lifts were rated significantly better than non-Manutention on the critical variable of working posture (p < 0.01) and observed effort (p < 0.05). Accident statistics on patient handling did not show decreased injury rates at twelve months. The difficulties of controlling variables in the workplace and of the measurement of complex handling tasks were limitations of this study.     

Toward an integrative approach of the industrial risk management process in France

Management in the field of environmental protection and risk prevention has evolved to the increasing participation of all stakeholders in the decision-making process. It certainly results from the development of the Information society and the global increase of knowledge of the population, combined with the concerns of the populations related to a sustainable development of our civilisation. Our ‘risk society’, following the big industrial disasters (Flixborough,Tchernobyl, Bhopal, Challenger, and more recently Toulouse), has also developed a cautious attitude towards the role of the expertise when it comes to assessing risks, along with a question of the ability of science to give definite answers.

This has lead in particular to the adoption of the Aarhus convention in 1998 and the evolution of several regulations in the developed countries. For example, in France the new law no. 2003–699 of 30 July 2003 about the ‘prevention of the technological and natural risks and to the compensation for the damages’ has introduced an important innovation into the process of technological risks prevention.

This law has enabled the involvement of the stakeholders in the decision-making process related to risk prevention and has urged the development of specific tools to deal with the complexity of risk management issues, in particular for those related to land-use planning.

As technical support to decision-makers in risk management from both public and private sectors, INERIS has played an important role for the evolution of the French risk management system.

This paper describes an analysis on the difficulty to control major accident hazards in an evolving context where the industrial systems becomes more and more complex and where the expectations of the civil society has increased. Then, the authors describe how an integrated vision for industrial risk management has emerged in France and is being implemented in a new law adopted after the Toulouse disaster.     

Operational risk assessment: A case of the Bhopal disaster

Accidental releases of hazardous chemicals from process facilities can cause catastrophic consequences. The Bhopal disaster resulting from a combination of inherently unsafe designs and poorly managed operations is a well-known case. Effective risk modeling approaches that provide early warnings are helpful to prevent and control such rare but catastrophic events. Probability estimation of these events is a constant challenge due to the scarcity of directly relevant data. Therefore, precursor-based methods that adopt the Bayesian theorem to update prior judgments on event probabilities using empirical data have been proposed. The updated probabilities are then integrated with consequences of varying severity to produce the risk profile.This paper proposes an operational risk assessment framework, in which a precursor-based Bayesian network approach is used for probability estimation, and loss functions are applied for consequence assessment. The estimated risk profile can be updated continuously given real-time operational data. As process facilities operate, this method integrates a failure-updating mechanism with potential consequences to generate a real-time operational risk profile. The real time risk profile is valuable in activating accident prevention and control strategies. The approach is applied to the Bhopal accident to demonstrate its applicability and effectiveness.     

For whom does safety pay? The case of major accidents

Government agencies regularly use the argument that ‘safety pays’ as a way of motivating employers to attend to occupational health and safety. This paper looks at the effectiveness of this argument in the case of catastrophic hazards. It suggests that, while it may be true that safety pays in an abstract sense, this is irrelevant unless it can be shown that safety pays for relevant decision makers. All too often it does not. The article illustrates its claims by drawing on the literature on the Zeebrugge, Bhopal and Piper Alpha disasters, as well as on a study of a mine disaster in Australia.     

Bhopal disaster—a personal experience

Bhopal Gas Tragedy was the worst industrial accident in the world where several thousand persons lost their lives. It occurred at the Union Carbide plant located inside the city of Bhopal and close to the railway station, at midnight of December 2-3, 1984 due to the leakage of MIC gas which took the local sleeping and floating population unawares.

This paper describes the experience of a transit passenger who reached the Bhopal Railway Station by train at about the same time when the deadly gas leakage occurred.     

Learning from the Bhopal disaster to improve process safety management in Singapore

The Singapore process industry is mainly made up of chemical and energy companies such as Mitsui Chemicals, Clariant, Exxon Mobil, Shell, Sumitomo, Petrochemical Corporation of Singapore and Infineum. Majority of these companies are located on Jurong Island, southwest of Singapore. Jurong Island houses nearly 100 leading petroleum, petrochemicals and specialty chemicals companies and the total investment is about S$42 billion in total. With a land surface area of only 716 km² and a high concentration of process plants, the Singapore government places strong emphasis on safety and risk management. In this paper, four process industry veterans from the government, academic and private sectors were interviewed. Through the interviews, the authors sought to understand the veterans’ perspectives on lessons that the Singapore process industry should learn from the Bhopal disaster. The veterans expanded their thoughts beyond the Bhopal disaster and provided many insights and suggestions critical to process safety management in Singapore and other countries. A systemic model of process safety management was derived from the interviews and key elements of operational process safety management were identified. In addition, a research agenda was identified based on the inputs from the veterans.     

The Bhopal gas leak: Analyses of causes and consequences by three different models

The Bhopal Gas Leak, India 1984 is the largest chemical industrial accident ever. Haddon's and Berger's models for injury analysis have been tested, together with the project planning tool Logical Framework Approach (LFA).

The three models provide the same main message: That irrespectively of the direct cause to the leakage, it is only two parties that are responsible for the magnitude of the disaster: Union Carbide Corporation and the Governments of India and Madhya Pradesh. The models give somewhat different images of the process of the accident.

Models developed for analysis of injuries can be used for analysing a complicated mega accident like the Bhopal gas leak, although different models might stress different aspects.     

Justice for Bhopal! And No More Bhopals! Three decades of national and international campaigning

Dissatisfaction with the responses of the responsible corporation, Union Carbide, and the Indian government to Bhopal resulted in a campaign by national and international NGOs (non-governmental organisations) over the past three decades. While initially the Indian and international campaigns were separate, over time greater international cooperation took place. In the immediate aftermath of the disaster local NGOs prioritised health, justice and rehabilitation issues, while international NGOs used Bhopal to question chemical industry process and environmental safety in their own countries, as well as internationally. Indian NGOs called on international NGO resources to gain legitimacy for their campaign, to use NGOs as proxies and to extend the geographical scope of the campaign, while international NGOs used Bhopal as an example to advance NGOs analyses and policies. Over the period of the campaign, Indian NGOs became more sophisticated in their campaigning. The international campaign has increasingly become an online campaign, involved in an image or reputational war with Dow Chemical, which took over Union Carbide, while the original campaign issues of justice and reparations over the process safety disaster were joined by similar issues related to environmental safety of abandoned toxic waste.     

The Bhopal gas tragedy: could it have happened in a developed country?

The Bhopal gas tragedy occurred in December 1984 wherein approximately 41 tonnes of deadly MIC was released in the dead of night. It caused the death of over 3000 people and continued life-long misery for over 300,000 with certain genetic defects passed on to the next generation. It happened in a plant operated by a multinational, Union Carbide Corporation, in a developing country, India. The tragedy has changed the chemical process industry (CPI) forever. The results have been new legislation with better enforcement, enhancement in process safety, development of inherently safer plants, harsher court judgements, pro-active media and NGOs, rights-conscious public, and a CPI management willing to invest in safety related equipment and training. These have already resulted in savings of several hundred lives and over a billion dollars in accident damages [Kletz, T. (1998a). Process plants: a handbook of inherently safer designs. London: Taylor & Francis. Sutton, I. Chemical Engineering, 106(5), (1999). 114]. However, thousands did not have to die for the world to realise the disaster potential of CPI. The question that still remains is whether such an accident could have happened in a developed country. The answer is ‘yes’, as a number of major accidents in the developed countries since 1984, such as the Piper Alpha oil platform fire (1988, 167 killed), the Zeebrugge ferry disaster (1987, 167 killed), Phillips petroleum fire and explosion (1989, 23 killed), the Challenger disaster (1986, 7 killed), Esso Australia Longford explosion (1998, 2 killed) have demonstrated. One or more of the following are the primary reasons for such disasters: The indifferent attitude of the management towards safety, the lax enforcement of the existing regulations by the regulatory bodies as well as unusual delays in the judicial systems. Such conditions can happen regardless of the level of development in a country. Hence, the Bhopal gas tragedy could have happened in a developed country too, albeit with a lower probability. This paper is concerned with the possibility and not with the probability value. It also points out that further significant advances in process safety will occur with fundamental research into the causes of accidents and with a move towards inherently safer design.     

The legacy of Bhopal: The impact over the last 20 years and future direction

Chemical process safety was not a major public concern prior to 1984. As far as chemical hazards were concerned, public fears focused on disease (cancer) and environmental degradation. Even a series of major process incident tragedies did not translate into widespread public concerns about major incidents in chemical plants that might disastrously affect the public. This situation changed completely after the December 1984 disaster at the Union Carbide plant in Bhopal. Not only was the public's confidence in the chemical industry shaken, the chemical industry itself questioned whether its provisions for protection against major incidents were adequate.

The recognition of the need for technical advances and implementation of management systems led to a number of initiatives by various stakeholders throughout the world. Governments and local authorities throughout the world initiated regulatory regimes. Has all that has resulted from the legacy of Bhopal reduced the frequency and severity of incidents? How can we answer this question? As we move into more and more globalization and other complexities what are the challenges we must address? According to the authors, some of these challenges are widespread dissemination and sharing of lessons learned, risk migration because of globalization, changing workforce, and breakthroughs in emerging areas in process safety.     

Fault propagation behavior study and root cause reasoning with dynamic Bayesian network based framework

The Bhopal disaster was a gas leak incident in India, considered the world's worst industrial disaster happened around process facilities. Nowadays the process facilities in petrochemical industries have becoming increasingly large and automatic. There are many risk factors with complex relationships among them. Unfortunately, some operators have poor access to abnormal situation management experience due to the lack of knowledge. However these interdependencies are seldom accounted for in current risk and safety analyses, which also belonged to the main factor causing Bhopal tragedy. Fault propagation behavior of process system is studied in this paper, and a dynamic Bayesian network based framework for root cause reasoning is proposed to deal with abnormal situation. It will help operators to fully understand the relationships among all the risk factors, identify the causes that lead to the abnormal situations, and consider all available safety measures to cope with the situation. Examples from a case study for process facilities are included to illustrate the effectiveness of the proposed approach. It also provides a method to help us do things better in the future and to make sure that another such terrible accident never happens again.     

浅析事故经济损失

近来,我国各类事故频繁发生,事故造成人员的伤亡或设备、装置、建筑物的破坏,给国家、企业和个人造成了很大的经济损失,也给社会造成了不安定因素.笔者认为事故发生后不仅要查清人员的伤亡情况、事故经过、原因分析、责任人处理、人员教育、措施制定,而且还要弄清事故经济损失的划分,进而对事故经济损失进行分析和统计,从而追究经济损失的承担者.本文介绍了国内外事故经济损失的划分、对比以及计算方法.参照国外的经验,根据我国的实际情况,对于直接损失和间接损失给出了详细的划分和计算的方法.