By looking at the history of process safety and the improvements that each decade has brought in terms of regulations and techniques, industry can invariably make itself safer. Determining how major incidents such as Bhopal, Flixborough, Chernobyl, Piper Alpha and others have influenced the industry, academia, government and subsequent regulations can offer a firm foundation for future endeavors. There is still research needed in the near future to further cement the foundation, and researchers and process safety experts need to pay attention to what incidents of this millennium are telling us about what is still needed in order to make process safety second nature.
The 19th century is known as the era of industrial revolution. Each technical progression has brought with it a certain amount of threat and hazardous activity. Chemical process safety was not a major public concern prior to almost the end of the 18th century. However, safety concerns were always there from the beginning of industrialization but not necessarily as we know or call it today. The primitive instinct of human beings to stay alive and protect themselves is probably the most visceral driver for the growth of process safety initiatives.1
Process safety: An ongoing phenomenon
The driving force for process safety has been primarily based on catastrophic events. With an increasing number of tragic incidents, the process industry and governments started taking initiatives to minimize loss of life and property, as well as to protect the environment. In the US, safety regulations started back in 1899 when the US government issued the River Harbor Act to avoid excess dumping in waterways. At the beginning of the 19th century, especially in the mines, thousands of innocent lives were lost because of the hostile environment. The year 1910 was reported as the worst, with 1,775 deaths in mines.2 These tragedies forced governments and local establishments to initiate regulatory regimes. In order to understand the growth of process safety, we have divided the significant initiatives and incidents into three broad sections. This categorization is based on the changes that took place between years 19301970, 19702000 and 20002012. This is shown in Fig. 1.
Fig. 1. Broad classification of process safety
development based on time period.
From 19301970. This period was mostly about establishing regulations. The Walsh-Healy Public Contracts Act in 1936 in US restricted working hours and employing child labor.1 This act also was concerned with occupational diseases, a basis of many present safety regulations. The 1947 presidential conference on industrial safety was another noteworthy step forward. Some other regulations were established in the years 19361969 (see Table 1). Individually, these acts did not have major impact in ensuring industrial safety but they played an imperative role for process safety to reach the position that it has achieved.
Congress passed the Occupational Safety and Health Act in 1970, which is a landmark legislation that put into motion programs that continue to evolve. Under this act, the Department of Health established the Occupational Safety and Health Administration (OSHA) with wide-ranging authority to enforce safety and health standards to ensure a safer workplace.1 Also, the US Department of Health and Human Services instituted the National Institute for Occupational Safety and Health (NIOSH) which had the responsibility to conduct research, provide recommendations to OSHA and train professionals for increasing awareness.1 In addition, the US Environmental Protection Agency (EPA) was established in 1970 to address environmental issues.
From 19702000. In the 1970s and 1980s, some of the worlds most shocking and tragic industrial accidents took place. Consequently, industries and government bodies everywhere were forced to rethink about the technology and management systems in industries from the safety point of view. Fig. 2 offers a timeline of the catastrophes during this time period.
Fig. 2. Timeline of major industrial disasters
between 1974 and 1989.
The Flixborough explosion in 1974 was by far the most severe disaster in the UK chemical industries and proved to be a major driver for process safety issues in the UK. As a result of these initiatives, at the end of 1974, the Advisory Committee on Major Hazards (ACMH) was implemented. The impact of Flixborough was reinforced by that of the Seveso tragedy in 1976.3
However, the unforgettable Bhopal gas disaster in India on December 3, 1984, which resulted in varying estimates of 3,000 to upward of 20,000 fatalities and injuries to another 500,000, was a wake-up call for the chemical process industry. Both the industry and the public became aware of the potential hazard of chemical facilities.2 This piloted the intensification of efforts within industry to ensure the safety of major hazard plants. Process safety finally gained absolute recognition as a standard practice. After the Bhopal tragedy, many regulatory initiatives were taken worldwide. In India, the Environment Protection Act (1986), the Air Act (1987), the Hazardous Waste (Management and Handling) Rules (1989), the Public Liability Insurance Act (1991) and the Environmental Protection (Second Amendment) Rules (1992) were promulgated.3
In 1984, the Mexico City disaster represented the largest series of boiling liquid expanding vapor explosions (BLEVEs) in history that killed almost 500 people.3 The nuclear disaster which took place on April 28, 1986, in Chernobyl, Ukraine, killed 56 people and caused the development of cancer and radiation sickness in many.3 The Piper Alpha accident on July 6, 1988, resulted in 167 deaths. The Piper Alpha Inquiry has been of crucial importance in the development of the offshore safety regime in the UK sector of the North Sea. On October 23, 1989, in the Phillips 66 plant in Pasadena, Texas, a massive gas explosion caused the death of 23 people and more than 300 injuries. 3
These incidents made it even more evident that implementation of safety legislation was indispensably necessary. Table 2 and Table 3 show the significant legislative and regulatory steps taken in the US and Europe.
Process safety in the new millennium
Process safety has certainly made remarkable progress. However, it is still impossible to adequately answer a simple question, Are we safe enough? The incidents that occurred in this millennium are a reminder that process safety has a long way to go.
The Columbia disaster on February 1, 2003, caused the death of all seven astronauts onboard and scattered shuttle debris over 2,000 square miles of Texas.11 This tragic incident can be traced back to flaws in decision making at NASA. The Columbia explosion was an important lesson for crisis communication professionals, as well. In fact, the NASA lessons can be mapped to many other catastrophes, such as the Piper Alpha or the Flixborough incidents, that reveal a sense of vulnerability, establish an imperative for safety, and reinforce the need for valid on-time risk assessments.11
The Macondo blowout in the Gulf of Mexico (GoM) on April 20, 2010, killed 11 employees and led to an uncontrolled oil spill lasting 87 days.12 This blowout was the most significant offshore incident in the US, and it had a profound impact on safety regulations in the GoM. The Drilling Safety Rule regarding well-bore reliability and well-control equipment was implemented on October 14, 2010. The Modified Workplace Safety Rule was put into place on October 15, 2010, based on the lessons learned from the Macondo blowout.
Finally, there was the Fukushima Daiichi nuclear plant incident in March 2011 that drew the attention of the global process and power industries, encouraging them to incorporate natural disaster risks in a hazard analysis study.12
Technical achievements pre-1970. Techniques to identify and evaluate hazards, calculate consequences and quantified event probabilities and risk (such as What-If, Checklist, HAZOP, Fault- and Event-Tree analyses) were developed in the middle of the 20th century. These developments occurred in some cases years or even decades before the well-known major incidents in the 1970s and 1980s. However, these catastrophic incidents reflected the need for more understanding and research regarding the underlying issues about process safety incidents. For example, the HAZard and OPerability (HAZOP) study, was developed by ICI in 1963, when a team was looking for ways to design a plant for phenol production with the minimum capital cost, but was considering possible deficiencies in the design.13 The Flixborough and Seveso incidents clearly showed the importance of identified hazards before fatal incidents occur, and HAZOP gained extensive popularity within operating and design companies. In the case of the Flixborough disaster, more than 40 tons of cyclohexane were released due to the rupture of a temporary bypass line. The temporary pipe was designed by a person who did not know how to design large pipes operating at high temperatures. After this incident, companies started to include procedures for management of change (MOC). Fault tree analysis (FTA) was developed in the early 1960s, and its use as a safety system and reliability technique quickly gained widespread interest, especially in nuclear and power installations. Since the development of FTAs, great efforts and advances (analytic methodologies, computer programs, computer codes) have occurred in the quantitative evaluation of fault trees.14
Technical achievements: 1970s and 1980s. In the US and Europe, models for pool formation, releases, evaporation and fire and explosions were refined in the late 1970s and the early 1980s.15 In these two decades, a series of fatal incidents (Fig. 3), reinforced the importance of these models and were one of the principal motivations for further research and improvements.
Fig. 3. Research motivated by major disasters
in the 1980s.
Bhopal increased substantially the interest and activity of the research and academic communities in a wide range of areas related with process safety,2 principally in reactivity hazards (employees did not have knowledge of the reactivity of MIC mixed with water16), inherent safety and chemical releases. The 500 deaths involved in Mexico City clearly demonstrated the importance and hazards involved in BLEVEs.3 Piper Alpha focused attention on jet fires, pool fires, carbon monoxide fires (initial CO poisoning caused most of the deaths) and explosions in modules with turbulence generation.17 This incident, and the sinking of the Alexander L. Kielland in 1980, were the most important events in the history of offshore operations in Europe, and together made a great impact in the use of quantitative risk assessment (QRA) techniques to assess offshore facilities.18
The aftermath of the Chernobyl disaster gave birth to the safety culture concept.19 According to the Phillips report,20 the cause of the incident was a modification in a routine maintenance procedure. This reinforced to the process industry the importance of incorporating management systems, such as MOC procedures. The 1970s and 1980s were decades of major incidents and great losses, but there is no doubt that these two decades made a great impact on what today we call process safety.
Technical achievements: 1990s to present day. During the 1990s, in response to new regulations and regulatory initiatives, collection of incident history data started at a rudimentary level. Advances in technology and the research conducted by different centers, such as the Mary Kay OConnor Process Safety Center (which was established in 1995), allowed for the development and availability of increasingly reliable incident databases.21 In the late 1990s, the Chemical Safety Board (CSB), in its MOC safety bulletin, highlighted the importance of having a systematic method for MOC, and how this is an essential ingredient for safe chemical process operations.
In the 1990s and early 2000s, the development of engineered nano-materials increased considerably. This development introduced a new area of research to process safety, an area where researchers are trying to understand the workplace exposure and environmental aspect of nanotechnologies.
Research needed in the near future
There is no doubt that the field of process safety has made great advances in terms of regulation and techniques in the last 40 years, but industry changes every day, and more sophisticated and complex processes are developed. This, combined with factors such as human errors (which will be always present), and challenges in creating and maintaining organizational memory, among others, is the reason why incidents continue to occur. Fatal incidents in this new millennium highlighted some of the areas of process safety where research is still needed (Table 4).
Dust explosion. Dust explosion research has been conducted on and off for more than 100 years.22 However, events such as the Imperial Sugar Co. incident in Georgia (14 deaths, 14 life-threatening burns, 38 total injures23) demonstrate the need for further research, awareness and management systems. In order to prevent these kinds of incidents, it is imperative to perform experimental and theoretical work to understand the chemistry and physics of dust cloud generation and combustion, flame propagation and potential ignition sources. It is also important to understand and develop models for fire and explosion of nano-materials.
Reactive chemicals. Reactive chemistry incidents continue to occur in the chemical processing industry, and in other industries which handle chemicals in their manufacturing processes. A CSB study, released in 2002, identified 167 reactive incidents that occurred between 1980 and 2001, which caused 108 deaths.24 More experimental and theoretical research is necessary to fully understand the kinetics and thermal behavior of industrial chemical reactions.4
Safety culture. The tragic Columbia shuttle incident showed the possible fatal consequences of bad industrial communication. It is important that research and safety professionals understand and evaluate good safety culture that enables the sharing of information and improvement of safety within the industries, taking into account different specialties and environments.
Nuclear safety. The Fukushima incident definitely changed the risk perception of nuclear power plants. Managers and researchers have a long journey in both risk communication and risk assessment models of nuclear power plants.
Make safety second nature
Although process safety was not recognized as a practice or discipline before the mid-1980s, concern about the health, safety and environment is intrinsic in human beings and as old as civilization. Great advances in safety regulations and techniques have occurred during the last century. But as industry grows and changes every day, processes present new challenges. Managers, operators and researchers must continue working together to improve their overall safety knowledge in order to make safety second nature. HP
1 Mannan, M. S., J. Makris and H. J. Overman, Process Safety and Risk Management Regulations: Impact on Process Industry, Encyclopedia of Chemical Processing and Design, ed. R. G. Anthony, Vol. 69, Supplement 1, Marcel Dekker, Inc., New York, 2002.
2 Mannan, M.S., et al, The legacy of Bhopal: The impact over the last 20 years and future direction, Journal of Loss Prevention in the Process Industries, 2005.
3 Mannan, M.S., editor, Lees Loss Prevention in the Process Industries, Volumes 13 (3rd Edition), Elsevier, 2005.
4 Qi, R., et al., Challenges and needs for process safety in the new millennium, Process Safety and Environmental Protection, 2012.
5 Berger, S., History of AIChEs Center for Chemical Process Safety, Process Safety Progress, 2009.
6 US Environmental Protection Agency, The Emergency Planning and Community Right-to-Know Act (EPCRA) Enforcement,EPA 550-F-00-004, March 2000, available at: www.epa.gov/osweroe1/docs/chem/epcra.pdf, accessed on: March 15, 2012.
7 US Environmental Protection Agency, The Clean Air Act (1990), available online at: www.epa.gov/air/caa/, accessed on: March 15, 2012.
8 US Occupational Safety and Health Administration, ProcessSafety Management (PSM) 2010, available online at: www.osha.gov/Publications/osha3132.pdf, accessed on: March 15, 2012.
9 US Environmental Protection Agency, Risk Management Plan (RMP) Rule (updated 2009), available online at: www.epa.gov/osweroe1/guidance.htm#rmp, accessed on March 16, 2012.
10 Willey, R.J., D.A. Crowl and W. Lepkowski, The Bhopal tragedy: Its influence on the process and community safety as practiced in the United States, Journal of Loss Prevention in the Process Industries, 2005.
11 American Institute of Chemical Engineers (AIChE), Lessons from the Columbia DisasterSafety and Organizational Culture, Center for Chemical Process Safety 2005.
12 McAndrews, K.L., Consequences of Macondo: A Summary of Recently Proposed and Enacted Changes to US Offshore Drilling Safety and Environmental Regulation, Society of Petroleum Engineers, Americas E&P Health, Safety, Security and Environmental Conference, Houston 2011. Available online at: www.jsg.utexas.edu/news/files/mcandrews_spe_143718-pp.pdf, accessed on March 16, 2012.
13 Kletz, T.A., Hazoppast and future. Reliability Engineering; System Safety, 1997.
14 Lee, W.S., et. al., Fault Tree Analysis, Methods, and ApplicationsA Review, IEEE Transactions on Reliability, 1985.
15 Pasman, H. J., et. al., Is risk analysis a useful tool for improving process safety? Journal of Loss Prevention in the Process Industries, 2009.
16 Center for Chemical Process Safety (CCPS), Guidelines for Investigating Chemical Process Incidents (2nd Edition), Center for Chemical Process Safety/AIChE 2003. Available online at www.knovel.com/web/portal/browse/display?_EXT_KNOVEL_DISPLAY_bookid=931&VerticalID=0, accessed on March 16, 2012.
17 Crawley, F.K., The Change in Safety Management for Offshore Oil and Gas Production Systems, Process Safety and Environmental Protection, 1999.
18 Turney, R. and R. Pitblado, Risk assessment in the process industries, Institution of Chemical Engineers.
19 Pidgeon, N.F., Safety Culture and Risk Management in Organizations, Journal of Cross-Cultural Psychology, 1991.
20 Company, P.P., A Report on the Houston Chemical Complex Accident, Bartlesville, Oklahoma, 1990.
21 Mannan, M. S., T. M. OConnor and H. H. West, Accident history database: An opportunity, Environmental Progress, 1999.
22 Eckhoff, R.K., Current status and expected future trends in dust explosion research, Journal of Loss Prevention in the Process Industries, 2005.
23 US Chemical Safety and Hazard Investigation Board (US CSB), Investigation Report on Sugar Dust Explosion and Fire, Report No.2008-050I-GA, 2009. Available online at www.csb.gov/assets/document/Imperial_Sugar_Report_Final_updated.pdf, accessed on March 15, 2012.
24 US Chemical Safety and Hazard Investigation Board (US CSB), Improving Reactive Hazard Management, Report No. 2001-01-H, 2002. Available online at: www.csb.gov/assets/document/ReactiveHazardInvestigationReport.pdf, accessed on March 15, 2012.
||M. Sam Mannan, PhD, PE, CSP, is a chemical engineering professor and director of the Mary Kay OConnor Process Safety Center at Texas A&M University. He is an internationally recognized expert on process safety and risk assessment. His research interests include hazard assessment and risk analysis, flammable and toxic gas cloud dispersion modeling, inherently safer design, reactive chemicals and run-away reactions, aerosols and abnormal situation management.|
||Amira Y. Chowdhury, BS, is a PhD student in materials science and engineering, and a research assistant at the Mary Kay OConnor Process Safety Center at Texas A&M University. She is a chemical engineer from the Bangladesh University of Engineering and Technology. Her research interests include hazard assessment and dust explosions. |
||Olga J. Reyes-Valdes, BS, is a materials science and engineering PhD student at Texas A&M University and research assistant of the Mary Kay OConnor Process Safety Center. She is a chemical engineer from Universidad Industrial de Santander, Colombia. Her research interests include reactive chemicals and run-away reactions, dust explosion, hazard assessment and risk analysis.|
Top 10 worst process safety incidents in history
This article discusses what the Mary Kay OConnor Process Safety Center at Texas A&M University in College Station, Texas, consider the top 10 process safety incidents in history. The incidents were ranked based on the cumulative impact on loss of lives and economic losses, and the resulting impact on the development of what today we know as process safety.
On the early morning of December 3, 1984, at the Union Carbide plant in India, a storage tank containing methyl isocyanate (MIC) was contaminated with water leading to a runaway reaction causing the release of more than 40 tons of toxic MIC gas through a relief valve. The incident killed more than 3,000 people and injured hundreds of thousands more. This was arguably the worst chemical industry incident in terms of people affected, however; it was just after this fatal tragedy that the chemical process industry became really conscientious of the importance of process safety and it gained complete acceptance as a standard practice.1 As a direct response to Bhopal, many regulatory initiatives were implemented worldwide. In India, this event led to the Environment Protection Act (1986), the Air Act (1987), the Hazardous Waste (Management and Handling) Rules (1989), the Public Liability Insurance Act (1991) and the Environmental Protection (Second Amendment) Rules (1992). In the US, the Emergency Planning and Community Right-to-Know Act (EPCRA) was promulgated in 1986,2 and the Clean Air Act Amendments (CAAA) were signed into law in 1990.1
On April 28, 1986, in a power plant in Chernobyl, Ukraine, an experiment performed in order to verify the emergency power supply of a reactor resulted in unfortunate consequences. The core of the reactor was blown out by two violent explosions causing a series of fires and the release of tons of radioactive materials. It is considered to be the worst nuclear disaster in history. The incident directly killed 56 people and influenced the development of cancer and radiation sickness of hundreds in the subsequent years.3 Before the incident, there were no written rules for the test that led to the catastrophic consequences. This fact has made the adherence to safety-related instructions as the most highlighted lesson learned regarding to process safety.4
3. Piper Alpha
Piper Alpha was a North Sea oil production platform. On July 6, 1988, the backup condensate pump pressure safety valve was removed for routine maintenance. However, since the maintenance could not be completed within the shift, it was decided to complete the remaining work the next day. As a temporary measure, the condensate pipe was sealed with a blind flange. Communication gaps between different shifts resulted in a catastrophe when the night shift crew unknowingly started the backup condensate pump after the failure of the primary pump. In just 22 minutes, fire broke out everywhere and the event escalated further because of design and operational flaws resulting in 167 deaths. The Piper Alpha incident was a wakeup call for the offshore industries. Significant changes in safety practice include development and implementation of safety case regulations in UK, adherence to a permit-to-work system and realistic training for emergency response.4
4. The Macondo blowout
The Macondo exploration well located in the Gulf of Mexico (GoM) was drilled by a deep water horizontal semi-submersible rig. On April 20, 2010, a blowout caused a fire and explosion on the rig that killed 11 employees and caused a major oil spill that continued uncontrolled for 87 days. A series of mechanical failures, lack of human judgment, faulty engineering design and improper team interaction came together to result in the largest oil spill known to mankind. The blowout was the biggest offshore incident in the US and it had a profound impact on safety regulations in the GoM. As a direct outcome of the Macondo incident, the Drilling Safety Rule regarding wellbore reliability and well control equipment was implemented on October 14, 2010. The Modified Workplace Safety Rule was also implemented on October 15, 2010, based on the lessons learned from the Macondo blowout.56
5. BP Texas City
On March 23, 2005, during the startup of an isomerization unit, the safety relief valves of a distillation tower opened due to overfilling, allowing hydrocarbon liquids to flow into a disposal blowdown drum with a stack, which were also overfilled, resulting in a liquid release. The evaporation of the hydrocarbons produced a flammable vapor cloud that ignited and led to a series of fires and explosions. Fifteen workers died and about 180 were injured.7 This incident led to major investigations including the milestone Baker panel report headed by former US Secretary of State James Baker III. This incident also resulted in significantly more interest in and attention to issues such as facility siting, atmospheric venting, leading and lagging indicators and safety culture.
6. The Flixborough disaster
On June 1, 1974, in a caprolactam production plant, a temporary bypass line ruptured, resulting in the leak of almost 40 tons of cyclohexane that caused a huge vapor-cloud explosion. The tragic disaster killed 28 people including all the employees working in the control room. There was the alarming possibility of killing more than 500 employees if it were a normal working day instead of weekend. Also, widespread damage to property within a 6-mile radius around the plant was another major consequence. The Flixborough explosion was a critical driver in moving process safety issues forward in the UK. As a result of the Flixborough incident, at the end of 1974, the Advisory Committee on Major Hazards (ACMH) was formed. The lessons learned from this disaster highlight the importance of HAZOP analysis, blast resistant control rooms and thorough studies prior to any modification in process plants.4
7. Mexico City
On November 19, 1984, in an LPG installation in Mexico City, the failure of the safety valve of an LPG storage tank caused an overpressure inside the tank and a pipe rupture, leading to a leakage of LPG followed by an ignition and violent explosions. Approximately 500 people were killed and more than 700 were injured.9 This incident represents the largest series of boiling liquid expanding vapor explosions (BLEVEs) in history.4 Mexico City clearly demonstrated the risk of BLEVEs in process facilities and lessons learned from this event have significantly impacted standards for design and operation.
On October 23, 1989, in the Phillips 66 plant in Pasadena, Texas, the rupture of a seal on a polyethylene reactor caused the release of highly flammable ethylene and isobutene gas, forming a gas cloud and leading to a massive explosion in less than two minutes. Twenty-three people were killed and more than 300 injured. The day before the incident, a maintenance procedure had been performed by contractor personnel. This incident underscored the importance of rigid adherence to operating procedures and the implementation of an appropriate management system for contract workers. In response to this incident and other incidents that occurred before in the 1980s (including Bhopal, Shell Norco, Arco Channelview and Exxon Baton Rouge), the US Department of Labor, Occupational Safety and Health Administration developed the Process Safety Management (PSM) regulation.10
9. Columbia disaster
The physical cause of the Columbia shuttle disaster was separation of insulation foam that then hit the carboncarbon reinforced panel of the left wing, thus damaging the thermal protection system. Aerodynamic pressure caused by superheated air destroyed the wing when the shuttle was reentering earths atmosphere at about 10,000 mph on February 1, 2003. The tragic incident caused the death of all seven astronauts and resulted in shuttle debris being scattered over 2,000 square miles in Texas. However, the underlying causes for the disaster can be traced back to flaws in decision making at NASA. The Columbia incident also provided important lessons for crisis communication professionals, as well. In fact, the lessons learned from the Columbia incident can be mapped to many other catastrophes such as the Piper Alpha or the Flixborough incident, covering issues such as sense of vulnerability, establishing an imperative for safety and valid on-time risk assessment.11
10. Fukushima Daiichi nuclear incident
On March 11, 2011, this incident drew the attention of the process and power industries around the world, encouraging them to incorporate natural disaster risk in any hazard analysis study. When a powerful earthquake hit the plant, the reactors shut down automatically. However, because of the earthquake and the following tsunami, a power blackout ensued, leading to the loss of cooling, which, in turn, led to overheating of the reactors (creating serious radiation hazards). Fortunately, no one was killed because of the radiation, but there may be long-term consequences to the workers and to the neighboring communities who were exposed to radiation.
These tragic events and the consequences of these events have provided us with numerous lessons that help our understanding of the hazards and risks of the modern process industry and, more importantly, how design, technology, equipment, management systems, human factors and safety culture can be used to improve the safety performance of the industry. Understanding the root causes of incidents and learning from mistakes within the company, as well as other organizations, is vital. These lessons need to be implemented both in the engineering and the management sectors.
1 Mannan, M. S., et al., The legacy of Bhopal: The impact over the last 20 years and future direction, Journal of Loss Prevention in the Process Industries, 2005. 18(46): pp. 218224.
2 Mannan, M. S., J. Makris and H. J. Overman, Process Safety and Risk Management Regulations: Impact on Process Industry, Encyclopedia of Chemical Processing and Design, ed. R. G. Anthony, Vol. 69, Supplement 1, pp. 168193, Marcel Dekker, Inc., New York, 2002.
3 Dara, S. I. and J. C. Farmer, Preparedness Lessons from Modern Disasters and Wars, Critical Care Clinics, 2009. 25(1): pp. 4765.
4 Mannan, M. S., Lees Loss Prevention in the Process Industries, 3rd Edition, Elsevier, 2005.
5 McAndrews, K. L., Consequences of Macondo: A Summary of Recently Proposed and Enacted Changes to US Offshore Drilling Safety and Environmental Regulation, Society of Petroleum Engineers Americas E&P Health, Safety, Security and Environmental Conference, Houston 2011. Available online: http://www.jsg.utexas.edu/news/files/mcandrews_spe_143718-pp.pdf, accessed on March 16, 2012.
7 Kaszniak, M. and D. Holmstrom, Trailer siting issues: BP Texas City, Journal of Hazardous Materials, 2008. 159(1): pp. 105-111.
8 Snorre, S., Comparison of some selected methods for incident investigation, Journal of Hazardous Materials, 2004. 111(13): pp. 2937.
9 C.M, P., Analysis of the LPG-disaster in Mexico City, Journal of Hazardous Materials, 1988. 20(0): pp. 85-107.
10 Guidelines for Vapor Cloud Explosion, Pressure Vessel Burst, BLEVE, and Flash Fire Hazards, 2nd Edition, August 2010, Process Safety Progress, 2011. 30(2): p. 187.
11 American Institute of Chemical Engineers (AIChE), Lessons from the Columbia Disaster-Safety and Organizational Culture, Center for Chemical Process Safety, 2005.