Analysis of the Buncefield Incident - Case Study Example

Name : xxxxxxxxxxx Institution : xxxxxxxxxxx Course : xxxxxxxxxxx Title : Buncefield incident Tutor : xxxxxxxxxxx @ 2009 Buncefield incident Introduction The Buncefield incident involved an explosion and fires at the Buncefield oil storage and transfer depot which occurred at Hemel Hempstead, Hertfordshire on 11 December 2005. The Buncelfield oil storage and transfer depot is a big tank farm owned by three firms. The firms are Hertfordshire Oil Storage Limited, United Kingdom Oil Pipelines Limited and West London Pipeline and storage Limited. Each of the above sites is categorized as a -tier site by the Control of Major Accident Hazard Regulations 1999. Fuel products to the site were supplied by three pipeline system all of which transported them in discrete batches separated by a boundary or buffer of mixed products. The buffer of mixed fuel was diverted to specific small tanks to be conveyed into the major large storage tanks in case the specifications permitted or transported back to the refinery as swills for re-refining. Explosions The explosions occurred at around 6.00 am on December 11 2005. The explosions occurred as a result of an overflow in the Tank 912 which occurred at around 5.20 am on the material day. Appropriate evidence showed that the protection systems which controlled overflows by closing down the supply inlets failed to operate. The overflow caused fuel to spill down the outer surface of the tank and through the air resulting to speedy formation of a rich formation of a strong mixture of fuel and air that collected in Bund A. at around 5.40, vapor from the mixture was seen at the western edge of Bund A, escaping out of the north-west corner of Bund A towards the west. The intensity of the vapor cloud increased to a depth of more than two meters and was escaping in all directions from Bund A. By 05.50, the vapor cloud was escaping off site close to the junction of Cherry Tree Lane and Buncefield Lane as a result of ground topography. The vapor extended to Northgate House and Fuji car parks and towards Catherine House (Contaminated land, 2009). The pumping pace down the T/K pipeline to Hertfordshire Oil Storage Limited West and towards Tank 912 steadily increased to about 890cubic meters per hour. By 06.01, the vapor cloud spread to the west close to the Boundary Way in the spaces between the 3-Com, Northgate and Fuji buildings. In the North-western side it extended to the nearest edge of Catherine House. It is estimated that it also extended to the north of the Hertfordshire Oil Storage Limited site but fortunately, it did not reach the tanker filling gantry. On the eastern side it got into the British Pipeline Agency Limited site. A widespread plume of smoke emanating from the burning fuel spread over to England and beyond. The plume was visible by people several kilometers away and it clearly be distinguished by satellite images (Buncefield Major Incident Investigation, 2009). The fire reached its peak at noon the following day. 25 Hertfordshire pumps, 20 support vehicles as well as 180 fire-fighters were brought to the site in an effort to control the fire. Secondary containment was lost because the bunds failed to entirely contain the escaped fuel and water used in fire-fighting. The bunds were destroyed by the strong heat of the fire resulting to a considerable loss of secondary restraint on the Hertfordshire Oil Storage Limited West and British Pipeline Agency Limited site limits and huge amounts of polluted liquids escaped of site. The fire service regained as much of the polluted run off as probable, but was not able to avert pollution of ground water and service water. Over 786, 000 liters of foam mixture and about 68 million liters of water were used to control the incident in the entire fire-fighting operations. The on-site investigations began on December 10 2005 although initial planning and information collection had started earlier. HSE who were in charge of the investigation secured the site to prevent distortion of evidence as well ensure safe clean up operations. The most affected sections of the site were too dangerous to access for periods extending to weeks or months after the incident (Buncefield Major Incident Investigation, 2009). Environmental impact Though the Department for Environment, food and Rural Affairs published a report showing that there were no significant impacts on the air quality from the Buncefield incident, the plume resulting from the fire had detrimental effects on human health and vegetation. Although the effects on the air quality were not widespread at ground level, the impact was a substantial pollution to the air. It did not affect the soil and grasses at ground level. The effects were however not severe as a result of the prevailing meteorological conditions and the high buoyancy of the plume which led to almost all the plume material moving to high altitude in the atmosphere. It then spread to a wide are with negligible amounts being left in the ground level (Buncefield Major Incident Investigation, 2009). The surface layer on the land was polluted by fuel and fire-fighting products. This was revealed after pits were excavated on the site as well as the surrounding area to evaluate the effect of the incident on land. Subsequent investigation revealed that the land was adversely affected by the incident. Close monitoring of the groundwater by the Environmental Agency revealed that major pollution occurred to the groundwater. The pollution mainly resulted from fire-fighting products, fuels and fuel related materials. The monitoring was conducted by the Environmental agency. The extent of the contamination was worrying and called foe the drilling of monitoring boreholes at specific places to conduct more assessments. The additional boreholes were aimed at enhancing groundwater monitoring network as well as increasing an understanding of flow and contaminant transport and the degree of pollution (Contaminated land, 2009). Perfluorooctane sulphonates (PFOS) a collection of chemicals were present in the foam that was used to control the Buncefield fire. These chemicals are hazardous in that they are persistent, bioaccumulative and toxic.. PFOS chemicals are used as additives in foams used in the control of fires because they assist in enhancing the spreading properties of the fire-fighting foam. PFOS seems not to degrade the natural environment and is thus widespread in both humans and the environment. The PFOS in the fire-fighting foam were found to be potential pollutants of land, surface water and groundwater. Investigations by Environment Agency and other parties that sampled the surface water as well as groundwater revealed that PFOS and other pollutants adversely affected the water on and off the explosion site. PFOS was detected in the Rivers Ver and Colne a few days after the explosion. The amounts however reduced to negligible quantities that were undetectable by the Environment Agency after a short duration (Contaminated land, 2009). Subsequent testing revealed trace amounts of PFOS in the rivers. No direct effects were detected at the time of the explosion or in the subsequent months on fish or other aquatic animals in these waters. Long term assessments will determine the environmental effects of the presence of PFOS and its related fluorinated compounds. Long term assessment of the groundwater have shown trace amounts of fuels, fuel-related products and remains from the fire-fighting foams in groundwater in various locations, but they are most widespread under and near the site. PFOS have also been detected in drinking water. PFOS have been analyzed to the levels of three micrograms per liter. Subsequent assessments revealed smaller amounts of the PFOS in drinking water. Further monitoring by the Environment Agency revealed that the groundwater underneath and in the locality of the Buncefield site has been polluted with fuels and fire-fighting foam by-products. This are of pollution is estimated to extend over one hectare threshold outlined in the Regulations (Buncefield Major Incident Investigation, 2009). Redeveloping the depot site The first step in redeveloping the closed deport site would be to ensure that it meets the PHS Regulations. PHS Regulations stipulate that the presence of hazardous chemicals above certain limits in a piece of land should first be approved by the local hazardous substance authority. The local hazardous substance authority is normally the local planning authority. HSE is a statutory consultant on all hazardous chemicals consent applications. Its responsibility is to evaluate the hazards and risks which would result from hazardous substances to individuals in the vicinity. It is on this basis that the HSE gives advice to the hazardous substances authority on whether or not approval should be made. In advising on approval, HSE may outline the conditions that should be enforced by the hazardous substance authority. The conditions should also be in line with limit risks to the public. In redeveloping the closed site, the people undertaking the exercise should ensure that the land meets the stipulated conditions in terms of pollution. If the site does not meet the stipulated limits, it will therefore be necessary to remove all the polluted firewater from the site as the first major step towards the redevelopment (Rainer, 2001). The groundwater and the surface water should also be assessed for pollution. This is aimed at checking whether the contamination level exceeds the stipulated amounts by the regulatory bodies. Any other polluted water like that resulting from rainfall or cleaning procedures should be removed from the site and stored in other locations within the nations together with the contaminated fire-water. The firewater is kept in the temporary storage until it is decontaminated and is ready for return to the natural environment. The firewater requires a number of refinement procedures to prepare it for return to the natural environment. The cleaning procedures involved should have minimal environmental effects. Once the firewater is ready for return to the environment, the Environment Agency should be informed in order to approve the return. Where necessary, the Environmental Agency may be forced to carry out certain tests to ensure that the water is ready for return to the environment. Re-development procedures are thus aimed at ensuring that the land is suitable for sustaining any other economic activity or for habitations. This can only be done after ascertaining that the site is free of any contamination that can affect human life. The pollution can also be reduced to insignificant levels that can not affect human life (Rainer, 2001). Summary of key findings Though investigations about the Buncefield incident are still in progress, there is enough information concerning major issues and key findings arising from the incident. Some of the key findings from the investigations into the accident include: Design and operation of storage sites The Buncefield incident concerned failures of primary, secondary and tertiary means of controlling fuel and associated fire-waters. Primary means include the tanks, pipes and vessels that contain liquids and the devices fitted to them to permit them to be safely operated. Secondary means are enclosed sections around storage vessels normally referred to as bunds constructed by concrete or earth walls. Their function is to contain any escaping fluids and any water or chemicals used in controlling fire accidents. Tertiary means are features such as drains designed to control the passage of chemicals off site, raised kerbs to stop liquids that have breached the bunds from spreading into the broad area around the site (Buncefield Major Incident Investigation, 2009). The occurrence of a enormous fuel vapor explosion validates the need to ascertain the reliability of the primary means of containment in order to ascertain that liquid does not escape from the containers in which it is usually meant to be confined. Safety and planning suppositions at fuel depots such as Buncefield have been founded upon fires of escaping fluids controlled by bunds whike the emergency services create the control. The formation of a large vapor cloud from tank storage was not taken into consideration which is a reasonable plausible scenario for land use planning reasons. One specific lesson from the Buncefield incident is thus that such a cloud can appear while a extremely flammable fluid like unleaded petrol is escaping from primary containment in a storage tank and where the route of escape entails cascading, fragmenting and dispersing the fluid from summit, that is, from the vents found at the top of the tank overfilled with the liquid (Buncefield Major Incident Investigation, 2009). The investigation also established that overtopping a tank with extremely flammable fuel has higher chances of resulting into an explosion or explosive mixture than collection from a lower level escape like that resulting from the failure of a tank. According to the investigation, the poor design of the tank could have played a role in the vapor formation at Buncefield. This implies that design and assembly of tanks and pipe work encouraged the creation of flammable vapors around the site. Secondary and tertiary ways of containment are important for environmental protection. The secondary containment offered by bunds around tanks is not of significant value where there is fast formation of vapor that will rapidly overflow the bund wall. Emergency response to incidents Enhancing the arrangements to avert fires and explosions should not be a justification to have poor emergency arrangements in the event of an accident. Proper emergency arrangements entail planning for both emergencies as well as efficiency of response mechanism. Firms in top tier COMAH sites are compelled by the law to have in place emergency plans to handle the on-site consequences of probable incidents and they must also offer local authorities the information necessary for the formulation of emergency to handle the off-site consequences. The public health implication of prospective vapor cloud explosions must be taken into account in both on-site and off-site emergency strategies. Despite that the public health effects of Buncefield seem to be insignificant, the case could have been different under different conditions (Buncefield Major Incident Investigation, 2009). Advice to planning authorities One of the most significant issues raise by the fire incident is the places where sites such as Buncefield should be located. The locations should be considered because they are a potential hazard to neighboring commercial and residential areas. Decisions about rebuilding activities near the Buncefield depot are vital to the livelihood of the people who work in such places and to the local economy (Rainer, 2001). Conclusion The investigation of the Buncefield incident revealed several issues that should be considered when designing the operations of such a site. It also revealed the possible developments that can be done on sites such as Buncefiled to avert such an accident in the future. Some of the matters of concern should be on the development and maintenance of appropriate primary containment. Primary containment is therefore vital in the designing of depot sites. The sites should be fitted with electronic monitoring devices that should raise alarm in case of abnormalities in the tanks and pipe work. The devices should be able to detect flammable vapors in the direct neighborhood of tanks and pipe work. The components should have appropriate response measures to abnormalities like automatic closure of inlets and incoming pipeline valves. These will certainly assist in the prevention of fire incidents as overflows or leaks will be avoided. Another factor to consider in the construction work is the extent in which the exterior of the tanks prevents or contributes to formation of flammable vapor. The recording of assessment, protection through detection by alarm systems and their availability for periodic analysis should be ascertained by the responsible authorities (Rainer, 2001). Bibliography Buncefield Major Incident Investigation. Retrieved on January 19, 2010 from Rainer Stegmann, Treatment of Contaminated Soil: Fundamentals, Analysis, Applications, Springer Verlag, Berlin 2001. Contaminated land. Retrieved on January 19, 2010 from Eidelson, M., 2001, Walks in Port Phillip: A Guide to the Cultural Landscapes of a City, Melbourne: City of Port Phillip. Rainer S., 2001, Treatment of Contaminated Soil: Fundamentals, Analysis, Applications, Springer Verlag, Berlin. Risk Assessment Guidance for Superfund, Human Health Evaluation Manual, Office of Emergency and Remedial Response, U.S. Environmental Protection Agency, Washington D.C. 20450. Read More