The Buncefield Incident and Its Effects on Surrounding Developments and the Environment - Case Study Example

CONSTRUCTION TECHNOLOGY The Buncefield Incident and Its Effects on Surrounding Developments and the Environment 1. Summary of the Buncefield Incident Several explosions occurred at the Buncefield Oil Depot on December 11, 2005. The explosions were followed by a fire that engulfed a wide area of the site including 20 large fuel storage tanks. The fire continues for several days resulting to damage of almost the entire site and large clouds of smoke into the atmosphere. Although there were fatalities, forty three people were severely injured and affected commercial and residential properties around the area. Twenty commercial units were destroyed, houses and other buildings in the neighbourhood were severely damaged, fuel supply for the Heathrow airport was interrupted due to the fire, and around 2000 people were evacuated (Apostol 2008, p.92). According to the report of the Buncefield Major Incident Investigation Board, the explosion and subsequent started when a safety system being employed to prevent overfilling the large fuel tanks failed to operate. Consequently, almost ten percent of the estimated 300 tons of petrol flowed out down to the side of the tank creating a vapour cloud with a mixture of air and petrol. The gas was cloud ignited by the emergency pump which incidentally was located within a fuel-rich part of the vapour cloud. The first explosion at around six in the morning was massive and created a huge fire (BMIIB 2008a, p.7). Although there were no reported severe health effects and deterioration of air quality caused the plume of smoke, escaped fuel, fire fighting foam, and water were believed to have polluted the area’s soil and groundwater. 2. The Incident’s Effects on the surrounding area 2.1 Effects During the Event The explosion and subsequent fire destroyed some 5% of the United Kingdom’s petrol stock and during the incident, the M1 North-South motorway was closed to traffic (Hiles 2007, p.501). Twenty large fuel storage tanks worth millions of pounds were lost and as the fire burned for several days, most part of the plant was destroyed. The black clouds of smoke covered the whole of southern England and beyond and evacuation of people from the surrounding area was implemented which include about 2,000 people. Since the fuel depot was in a large industrial estate, the incident destroyed commercial units of about 20 companies and another 60 buildings were damaged by the blast. In addition, the huge explosion also damaged some 300 houses in the surrounding residential area (Apostol 2008, p.92). 2.2 Effects After the Event After the Buncefield incident, many businesses were directly or indirectly affected through the disruption of the supplies. Around 16 companies had to relocate which cause job moves for 1,422 people. The incident created 79 redundancies where 21 of those found new jobs later. Moreover, the claims for damages of those that were affected went to hundred of million pounds (Hiles 2007, p.505). The explosion and subsequent fire at Buncefield Oil Depot was reported to have affected the quality of soil and water around the area. The pollution may come from the escaping fuel and fire fighting foam and water. However in the initial report of the Buncefield Major Incident Investigation Board, indicate that there was contamination of the surface layers of lands in the neighbouring area around the site. PFOS or Perfluorooctane Sulphonate, an additive for fighting foams were detected in the Ver and Coine river but there was no mention of the impact of these hazardous chemicals to the fish and aquatic species in the report although PFOS has been classified as ecotoxic, persistent, and bioaccumulative (Vince 2008, p.30). Although the air quality around the site was not severely affected, the immediate concern after the incident was the risk to health and safety of the people thus caution was still recommended by the concern authorities (Orme et al. 2007, p.245). Two years after the incident, the Environment Agency monitoring the extent of contamination that might caused by the incident to the surrounding area reported in February 2007, that the underground water up to two kilometres around the site has been contaminated by hydrocarbons and fire fighting foam. Consequently, major treatment was carried out and up to 5 million litres of effluent at sewage treatments plant in the site was uplifted and disposed (Institution of Chemical Engineers 2008, p.49). 2.3 Incident’s Contamination of Land and its Effects on the Environment The issue about the Buncefield incident’s possible contamination of land and its negative effect on the environment had been emphasized the Buncefield Major Incident Investigation Board. This is because there is a strong possibility that contaminated firewater can cause off-site environmental damage. For instance, although they are clean and with relatively low toxicity level, halogenated hydrocarbons or halons can cause damage to the environment since they have been found to contribute to the destruction of Earth’s ozone layer. Similarly, PFOS, a component of fire fighting foams, which since year 2000 are being phased out, are ecotoxic and harmful to the environment (Vince 2008, p.30). For above reason, the former Buncefield Oil Depot site is no longer a safe place and can be considered a contaminated land and subject to regulations applied for redevelopment. Moreover, value of contaminated lands devaluate significantly along with strict regulation and liability for treatment. The risks associated with contaminated land such as Buncefield are assessed in terms of pathways or the route in which a hazard can go and affect the target (Harris et al. p.4). For instance, the presence of contaminants in the soil and water may affect the residents of the future residential units that will be built on top of the previous incident site. Redevelopment of contaminated land therefore entails more responsibility than ordinary land development. 3. Steps a Developer should take to redevelop the depot and build residential and commercial property In principle, contaminated land is not fit for human activity since it is potentially risky as far as human and environmental health is concern due to its hazardous properties. One of the risk involve is the possibility of pollutant migration through groundwater, soil, and the air as with former Buncefield Oil Depot site. For this reason, a contaminated land is not suitable for redevelopment and may require substantial clean-up before any construction can proceed. However, the cost of the clean-up may discourage a developer particularly if the level of contamination is wide and deep. A developer who wants to push through the project may need to undertake some essential process such as study and investigation of the site to determine the extent of contamination and subsequently come up with remedial actions (Best & Valence 2002, p.200). Redevelopment of contaminated land involves removing contaminants from polluted sites such as former Buncefield oil depot. Many construction companies are obligated to implement Part IIA of the Environmental Protection Act 1990 while building in a contaminated land and consequently research had been carried out of the construction industry and most of them are now well experienced in dealing with redevelopment. More importantly, consultants, contractors, and other construction professionals are undergoing training in areas such as development of objectives for risk assessment, site investigation and estimation of risks at site, constraints and site-specific legislative requirements, and remedial strategies including monitoring and aftercare operations (Yong & Thomas 2003, p.72). As part of the regulatory requirements, the first step or in Phase 1, a construction company must take involve itself in hazard identification and assessment. In this stage, the company should gather and review data that include desk studies of site history and contamination that were identified. Desk studies include research on historical background of the site such as previous industrial uses. The company may include information sources such Ordinance Survey Maps, geological and hydrological records, previous site owners, the Environmental Agency, landfill planners, and other environmental health authorities. In Phase II, the company must perform risk estimation by making a detailed study of the ground to confirm the presence of contamination and identify potential risks. This may include site investigation and making preliminary inspection to recognize, identify, and interpret significant signs on site. The company may also obtain samples of vegetation, water, waste soil, and make detailed examination using trial pits or boreholes (Best & Valence 2002, p.200). Evaluating the risks at site include review of information to identify and determine if the earlier estimated risks are either tolerable or unacceptable. However, not all risk assessment would necessarily go through this stage since completion of a hazard assessment is acceptable. This is because a completed risk assessment may already determine if the risks are unacceptable and requires remedial action to reduce the risks to an acceptable level. Site investigation normally requires physical sampling on site that may include techniques such as site walkover, surface gas emission testing, geophysical testing, false colour infrared photography, thermography, tracer gas testing, boreholes, trial pits and trenchers, probing techniques, static cone penetrometer, window sampling, gas and water monitoring wells. The process of investigation on a contaminated land generally depends on the developer or the construction company’s requirements. In Buncefield for instance, the desk study may reveal information such as contamination by fire fighting foam and water thus the site investigation may focus on this issue and decide to collect data by installing a monitoring wells. In other words, the extent of the investigation of the former Buncefield Oil Depot depends on professional judgements that are based on the understanding of the site usage, history, intended use, and other details gathered from the desk study. The credibility of the results of investigation is however, depends on different factors such as the quantity of soil and water taken and tested. It may also include how exploratory holes are laid-out and maintained, and the constancy of subsequent monitoring (Hester & Harrison 1997, p.18). Since the need for remedial action is already known, the remedial strategy should be developed. The remedial action that a company should take can be contamination-related which would give more focus on determining the type of remedial action to take. In may also be an engineering-related action such as improving the stability or load bearing capacity of the ground or management-related such as cost of improving the site and time constraints and management (Yong & Thomas 2003, p.75). Once risk assessment establishes that there is indeed an unacceptable risk at site, remedial measures should consider carrying out additional work during the redevelopment to reduce or completely eliminate the hazard. Reducing a hazard may be done by encapsulation or separation or by using barriers to contain contaminant movements. If redevelopment is intended for commercial or residential property then this work may be more complicated since it includes considerations on future liability. For this reason, a company’s remedial work should give more focus not only on engineering feasibility and economics but on health and safety and environmental impact (Hester & Harrison 1997, p.20). Risk avoidance techniques may be adopted by the company for dealing with contaminated land such as the former Buncefield site. These include changing land use, site layout and location of services and other infrastructure. However, these may not be feasible if the site is intended for housing since change use is nearly impossible. The best solution that may be employed by the company is to use engineering or process-based methods to remove or isolate the sources of contamination or modification of the pathway. Removal or isolation of contaminants through engineering can be done by excavation and off-site disposal, in-ground barriers such as cut off trenches and slurry walls, and more importantly, control of contaminated ground water. Through process-based method – biological, chemical, physical, solidification, alteration of the state of contaminates may be possible by stabilizing or destroying contaminants once and for all. However, this method depends on the capability of the developer that would probably choose a lighter method due to economic constraints. According to Hester & Harrison (1997, p.21), economic considerations is the common deciding factor and an option that entails more expenditure is unlikely to be considered unless the benefit is far greater than the cost. However, whatever solution is taken, the efficiency of the company’s remedial action can be measured by systematic sampling and testing programme. For instance, the company can carry out post-treatment validation exercise to find out if the proposed remedial will going to be effective or not. However, not until contaminations in Buncefield are dealt effectively, a developer should not proceed with the redevelopment. 4. Summary of Key Findings The explosion and subsequent fire at the Buncefield Oil Depot in 2005 was the result of a failed safety system. The incident not only damaged the entire site but properties around the area. Although there were no deaths reported, 43 people were injured and 2000 other evacuated. Moreover, the blast destroyed a number of buildings and severely damaged commercial and residential units around the site. The initial investigations conducted after the incident did not mention any significant air pollution from the black thick smoke around the area but suggested that there was contamination of the surface layers of lands. Moreover, traces of toxic PFOS were found in the rivers around the site. The Environment Agency years later also confirmed that the underground waters around the site are contaminated with hydrocarbons and fire fighting foams. For this reason, content of sewage treatments plant at the site were uplifted and disposed to avoid further contamination. Contaminated lands such as those in previous Buncefield Depot is human and environmental health risk and are not directly suitable for redevelopment particularly for commercial and residential units. Redevelopment is only possible through mitigation of risks such as cleaning and reducing the level of contamination. A developer must undertake a step by step process that include hazard identification and assessment which include a desk study, site investigation, evaluation of the hazards identified, and remedial actions that should be taken to improve the site. These processes may vary depending on the developer’s capacity and the extent of the contamination. However, whatever decision or action a developer might do, their remedial action should ensure that contaminations are reduced to a level where it cannot affect the health and safety of the people that would occupy the commercial and residential units they are going to build at the former Buncefield Oil Depot. 5. Reference List Apostol I. 2008. Risk Assessment as a Basis for the Forecast and Prevention of Catastrophies. IOS Press, Netherlands Best R. & Valence G. 2002. Design and Construction: Building in Value. Butterworth-Heinemann, UK Harris M. & Herbert S. 1994. Contaminated Land: Investigation, Assessment and Remediation. Thomas Telford, UK Hester R. & Harrison R. 1997. Contaminated Land and its Reclamation, Royal Society of Chemistry, UK Hiles A. 2007. The Definitive Handbook of Business Continuity Management, John Wiley and Sons, UK Institution of Chemical Engineers. 2008. Hazards XX: Process Safety and Environmental Protection, Harnessing Knowledge-Challenging Complacency. IChemE, UK MIIB-08a. 2008. The Buncefield Incident: 11 December 2005, The Final Report of the Major Incident Investigation Board Volume 1. The Office of the Public Sector Information, UK Orme J. et al. 2007. Public Health for the 21st Century. McGraw-Hill International, Poland Vince I. 2008. Major Accidents to the Environment: A Practical Guide to the Seveso II directive and COMAH regulations. Butterworth-Heinemann, UK Yong R. & Thomas H. 2001. Geoenvironmental engineering: Geoenvironmental impact management. Thomas Telford, UK Read More