Health and Safety Assignment A

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brief essay on H&S of 4 specified chemical disasters
  Health and safety assignment A Four other major accidents Introduction to professional studiesDaniel Iles   ContentsChapter 1 ± Introduction 1.1 Introduction Chapter 2 ± H & S of accidents 2.1 The explosion at Shell¶s Pernis refinery in 19682.2 The µDioxin¶ release at Seveso in 19762.3 The Bhopal disaster in 19842.4 The Piper Alpha disaster in 1988 Chapter 3 ± could a similar accident happen today? 3.1 Could a similar accident occur in the current H&S climate? Chapter 4 ± Conclusion 4.1 Conclusion    1.1 IntroductionThis assignment will utilise the knowledge I have gained from studying healthand safety during the ³introduction to professional studies´ module. Four major industrial accidents will be studied and the health and safety measures in placeprior to these accidents will be critically analysed in a case by case fashion for each accident.I will then put forward an argument stating whether a similar accident couldhappen in today¶s industry and then make a conclusion.2.1 The explosion at Shell¶s Pernis refinery in 1968This accident was a vapour cloud explosion caused by trying to break anemulsion through excessive heating.One of the ironic things noticeable is that the main reason for this accident wasthe result of an H&S procedure at the Pernis site.That procedure was the decision to treat the untreated crude oil with water todissolve salts and therefore prevent the risk of severe corrosion and other hazards that could have led to an accident in its own right. Unfortunately bytreating the oil with water a stable emulsion was formed which they decided toheat to try and break the emulsion. (Ministry of Social Affairs and Public Health,Report concerning an inquiry into the causes of the explosion on 20th January,1968 at the premises of Shell Nederland Raffinaderij in Pernis. State PublishingHouse, The Hague, Holland (1968))Heating oil has long been recognized as hazardous by oil companies (AMOCO,Booklet No.1, Hazard of Water, 5th edn , AMOCO, Chicago (1964))Perhaps with the heating of the oil it would¶ve been safer to stir the tank then let itsettle to stop things like this accident occurring. At the very least someoneshould¶ve been observing the temperature of the contents and checking for fumes above the tank. If a HAZOP or risk assessment or H&S tool of similar kindhad been conducted on this procedure things may have turned out differently.We have to bear in mind that this accident occurred in 1968 and was before theany H&S culture, so to speak, and therefore technology and safety precautionswe take for granted nowadays weren¶t in place at that time.When a chemical plant is designed and built health and safety should be a major concern but in the case of Pernis some mistakes were made. One commontheme in major chemical plant disasters is that the plant is located too near tohuman habitation. This is also the case in the Pernis incident as many nearbybuildings in Rotterdam were damaged by the explosion (Ministry of Social Affairs  and Public Health, Report concerning an inquiry into the causes of the explosionon 20th January, 1968 at the premises of Shell Nederland Raffinaderij in Pernis.State Publishing House, The Hague, Holland (1968))Similarly the site management buildings and offices should be as remote aspossible, within reason, from the sources of explosion and fire. In the case of Pernis major damage was inflicted on the main office buildings. (Health & SafetyCommission Advisory Committee on Major Hazards - SECOND REPORT,HMSO)2.2 The µDioxin¶ release at Seveso in 1976In the Seveso incident a toxin known as dioxin poisoned a densely populatedarea after being released from a TCP chemical works in an explosion caused bya runaway reaction.Some safety measures and associated problems: y The main H&S tool of interest in this incident is a pressure release device(bursting disc) that discharged directly to the atmosphere. This was theweak link in the chain that led up to the disaster but there a lot of other things to consider.For one ± why was this device used in the first place. If management hadconducted a simple ³what if´ analysis for a worst case scenario for theTCP plant they would surely have considered a runaway reaction. In factthe bursting disc, a supposed safety device, increased the temperatureand pressure during the runaway reaction, which in turn increased thelevel of dioxin formation.If they had they may have came up with the simple solution of a vent valvethat transferred to a dump tank/condenser combo.The problem of the bursting disc had been there since the plant wasmodified a year earlier. (Safety in the process industries, Butterworth-Hienmann 1990, Ralph King, pg 91-93)Such containment vessels such as a ³dump tank´ or ³blow-down´ vesselhave been widely used in nuclear power plants for water cooled reactorsrather than venting straight to the atmosphere. There probably wouldn¶thave been a Seveso disaster if the Icmesa plant had used a vessel suchas this. (Seveso: A paradoxical classic disaster, B. De Marchi, S.Funtowicz, and J. Ravetz, pg 3)The Icmesa plant probably couldn¶t have chosen a worse safety devicethan the pressure release valve, and this shows that they clearly hadn¶tconsidered what would happen if a runaway reaction had occurred.
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