Bhopal Gas Tragedy- The Night of Death


Published on

Published in: Health & Medicine, Business

Bhopal Gas Tragedy- The Night of Death

  1. 1. Bharti Singhla 2011CH10151 Archana Kumari 2009CH70125 Criti Mahajan 2009CH70134 Paridhi Khandelwal 2009CH70150 Sweekriti Dhanpuri 2010CH10
  2. 2. • Background 1. Background of Union Carbide 2. Chemical reaction in the plant 3. Bhopal Plant Layout 4. Methyl isocyanate: physical and chemical properties 5. Safety systems installed in case of MIC leak 6. Events prior to the tragedy 7. Chronology of events on 2nd Dec, 1984 8. Theories for the cause of event 9. After effects of the disaster 10.Treating the waste 11.Changes in the policies introduced 12.Fate of the company 13.Lessons from Bhopal gas tragedy 14.Suggested checklists to monitor small and large chemical disasters
  3. 3. • Union Carbide India Ltd. (UCIL) – Indian subsidiary of Union Carbide Corporation (UCC), American firm • 1969 – UCIL plant in Bhopal begins operating , formulation of carbamate pesticides from chemicals imported from US • 1975 – License issued to manufacture carbaryl pesticide (Sevin) • 1979 – Production started, capacity of the plant – 5250 tons/year • Demand decreasing every year and so the production also decreasing 1981 – 2704 tons/year, 1983 - 1657 tons/year
  4. 4. • Manufactured by the reaction of monomethlyamine and phosgene. 1. Monomethyl amine 2. Phosgene 3. Methyl Isocyanate (MIC) 4. Alpha – Naphthol 5. Sevin
  5. 5. Phosgene Stripper Tail Gas Pyrolysis COCl2 MMA Reactor Chilling Unit HCl MIC MIC storage
  6. 6. • • • • • • • • • Volatile, liquid, colourless gas with strong and sharp odour Flash Point – -18oC Molecular weight: 57.051 g/mol Low solubility in water Flammability: Highly flammable Flammable Range: 5.3% to 26% (concentration in air) Highly volatile Reacts readily with many substances that contain N-H or O-H groups. With water, it forms 1,3-dimethylurea and CO2 with the evolution of heat (325 calories per gram of MIC) • If the heat is not efficiently removed from the mixture, the rate of the reaction will increase and rapidly cause the MIC to boil • Easily polymerizes (exothermic process)
  7. 7. Hazard Rating Flammability Reactivity • • • • • NFPA 3 2 Flammable and Reactive Poison Inhalation Hazard Poisonous Gases are produced in fire In UC, it was called Liquid Dynamite Exposure symptoms includes coughing, chest pain, dyspnea, asthma, irritation of the eyes, nose and throat, as well as skin damage. Higher levels of exposure, over 21 ppm, can result in pulmonary or lung edema, emphysema and hemorrhages, bronchial pneumonia and death. Hazard Rating Key: 0-minimal, 1-slight, 2-moderate, 3-serious, 4-severe
  8. 8. 1. Vent Gas Scrubber - used caustic soda to neutralize toxic gas exhaust from MIC plant and storage tanks before release through vent stack or flare 2. Flare - burnt toxic gasses to neutralize them 3. Refrigeration System – Refrigeration unit with capacity of 30 ton was installed to keep MIC at temperatures of 0-5 degrees C 4. Firewater Spray Pipes - to control escaping gases and cool over-heated equipments 5. Safety valve - this valve was placed between MIC storage tanks and MIC holding tank in SEVIN production area 6. Extra tank – Tank E610 and E611 were for normal use , and E619 for emergency
  9. 9. Dec 1981 Plant operator killed by Phosgene Gas Leak • Medical Officer brought into notice the hazard posed by the factory •Jan 1982- 24 persons affected by phosgene •Feb 1982 – 18 persons affected by MIC leak May 1982 Report by Americans on UCC plant 1983 onwards All energy concentrat ed on cost cutting • 200 skilled workers asked to • Reported leaks of phosgene, resign MIC and chloroform • Only 1 person in control • Ruptures in pipework and room sealed joints • June 1984 - 30 ton •Poor adjustment of certain refrigeration unit cooling the devices where excessive MIC system was shutdown pressure could lead to water • Oct 1984 - Vent Gas entering the circuits Scrubber was turned off, Flare was extinguished
  10. 10. 8-9pm Around 9:30 pm By 10:30pm • MIC unit workers to flush several pipes running from the phosgene system to the scrubber via the MIC storage tanks • Maintenance Dept not asked to install the slip bind • Temp. of MIC tank between 15 & 20 deg C. • One Bleeder valve blocked, water accumulated in the pipes • Plant supervisor still ordered to continue washing • Water entered the relief valve pipe • Water flows from the relief valve pipe into the process pipe and then flows into the tank E610 • Change of Shift, Water Washing still continues
  11. 11. 11 pm to 12 am 12:30 am • Pressure rise in tank E610 from 2psi to 10 psi • MIC leak near the scrubber • Set-up water spray to neutralize leaking MIC • Pressure indicator of Tank E610 pointing to the maximum reading of 55psi • Hears safety valve pop, rumbling sound from the tank , and heat from the tank • Tries to engage gas vent scrubber but caustic soda doesn’t flow • Cloud of gas escapes from the scrubber stack • Operators turn on the fire water sprayers but water cannot reach the gas cloud From 12 :40 • Try to cool Tank E610 with the refrigeration system but the Freon onwards had been drained. Gas escapes for about 2 hours.
  12. 12. The disaster happened as a result of exothermic reaction between water and MIC which led to the rupture of safety valve of the MIC storage tank. There are two theories explaining how water entered the tank: 1. Water Washing Theory (theory taken by Indian government) 2. Sabotage Theory (theory taken by Union Carbide Corporation)
  13. 13. Water Flushing Theory: • The media played a significant role in establishing the WATER WASHING THEORY as a plausible explanation. • At the time, workers were cleaning out a clogged pipe as a part of routine maintenance. • They did not go through the plant standard operating procedures and hence they failed to insert the slip-blind plate used to prevent water from going inside the tank. • The water was supposed to be drained through drainage nozzles. Due to the existence of large quantities of rust in the pipe, these nozzles were plugged with dirt. • Water supposedly backed up into the pipelines and eventually found its way into the tank because the slip blind plate wasn’t in its place.
  14. 14. Sabotage Theory: • The investigation was done by the engineering consulting firm “Arthur D. Little”. • It was concluded that an angry employee secretly introduced a large amount of water into the MIC tank by removing a mete and connecting a water hose directly to the tank through the metering port. • Carbide claimed that such a large quanitity of water could not enter the tank by accident, available safety systems couldn’t deal with intentional sabotage. • UCC found three main weak points in the water flushing theory. Water head was not enough to push such a large quantity (2000 lbs) of water to the MIC tank An intermediate valve found closed after the accident. The intermediate line found dry.
  15. 15. Weather Conditions: • The high moisture content in the discharge when evaporating, gave rise to a heavy gas which rapidly sank to the ground. • A weak wind which frequently changed direction, which in turn helped the gas to cover more area in a shorter period of time (about one hour). • The weak wind and the weak vertical turbulence caused a slow dilution of gas and thus allowed the poisonous gas to spread over considerable distances.
  16. 16. Supporting events: • Not following safety regulations as that followed by UCC plants in USA. For eg. to reduce energy costs, the refrigeration system was idle. The MIC was kept at 20 degrees Celsius, not the 4.5 degrees advised by the manual. • The flare tower and the vent gas scrubber had been out of service for five months before the disaster. • The MIC tank alarms had not worked for four years. • The steam boiler, intended to clean the pipes, was out of action for unknown reasons.
  17. 17. Contd… • Use of a more dangerous pesticide manufacturing method for decreasing generation cost. • The gas leaked from a 30 m high chimney and this height was not enough to reduce the effects of the discharge. • Insufficient maintenance and inadequate emergency action plans. • Lack of awareness of the potential impact of MIC on the community by the people operating the plant. • Lack of skilled operators. • Inadequate community planning, allowing a large population to live near a hazardous manufacturing plant.
  18. 18. •A house to house symptom survey conducted in 1993: Respiratory diseases 65.7% Neurological 68.4% Ophthalmic 49% Reproductive 43.2% (of people in reproductive age) • 1990 : Bhopal Group for Information and Action (BGIA) ― Testing by Citizens Environmental Laboratory, Boston ― Presence of at least seven toxic chemicals • Lead and mercury found in breast milk samples: Greenpeace
  19. 19. •Poorly understood, 120000 chronic survivors •Respiratory: Persistent fibrosis, Chronic Bronchitis, TB •Ocular: Chronic conjunctivitis, Corneal opacity •Reproductive: Pregnancy loss, Higher infant mortality •Gastro-intestinal: Hyperacidity, Chronic gastritis •Neurological: Impaired memory and motor skills •Genetic damage to plants •Rivers and lakes polluted by chemicals: destroying aquatic and animals thriving on the sources Children born with genetic defects Polluted water sources Raina V. , Survivors of the Bhopal Gas Disaster, Twenty five years after
  20. 20. •350 metric tonnes of toxic waste •Global toxic hot-spot : Greenpeace •Groundwater and soil contaminated with heavy metals and carcinogenic chemicals •Dicholorbenzene, Hexachlorobutadiene, Tricholoroethane •Mercury, lead, cadmium •Poisoning drinking water sources in 16 communities: effecting 25,000 people •Hexachlorobutadiene : potent kidney toxin , a possible human carcinogen. •Trichloroethene: impairs foetal development The solar evaporation pond Factory’s chemical waste Broughton E. , The Bhopal disaster and its aftermath: a review, Environmental Health: A Global Access Science Source 2005, 4:6
  21. 21. •Pyrolisis by plasma torches: Dissociate the organic molecules •Stoichiometric amount of oxygen: Reforms the dissociated elements of the waste into Syngas •Syngas can then be used as a fuel •Metals can be recovered by HCl or Na2S
  22. 22. •Environment Protection Act (1986): •Stronger inspections standards and control over hazardous substances •Personal responsibility from corporations • Ministry of Environment and Forests (MoEF) •Factories (Amendment) Act (1987): •Safeguards in use and storage of hazardous substances •Mandatory worker safety training •Air (Amendment) Act (1987): •Governmental consent to release pollutants •Hazardous Waste Rules (1989): •Government “authorize” companies as to what they can pollute with •Public Liability Insurance Act (1991): •Insurance to cover death, injury, or damage resulting from a disaster
  23. 23. •Emergency Planning and Community Right to Know Act-1986, U.S. •An annual report on all toxic, hazardous chemicals released •List of chemicals to fire department, emergency responders and local government •Emergency response plans to handle accidental emission: local agencies •Accident to be reported immediately •Responsible Care Program-1985, Canada •Performance measurement and reporting •Implementation of a security code •Management system to achieve and verify results •Independent certification of standards Sheehan H. E.(2011), The Bhopal gas disaster: focus on community health and environmental Effects, Indian Journal of Medical Ethics, VIII- 2
  24. 24. •1989: All settled for a mere 450 million USD •Amounted to Rs. 10,000 per victim •Charges against Warren Anderson •1999: Dow chemicals purchased UCIL for 3.9 billion USD •Dow chemicals refuses to take responsibility for the toxic waste •Nature of the chemical industry •Re-think the necessity to produce potentially harmful products in the first place •Despite greater government commitment to protect public health, forests, and wildlife, policies geared to developing the country's economy have taken precedence
  25. 25. 1. Management of major hazard installations: competent management, should be familiar with exigencies of major hazard operation 2. Hazard from highly toxic substances has been insufficiently appreciated. 3. Runaway reaction in storage. 4. Hazard of an exothermic reaction between a frozen fluid and water (corrosion, blockage or freezing) 5. Relative hazard of materials in process and in storage 6. Relative priority of safety and production 7. Limitations of inventory in the plant 8. Set pressure of relief devices. 9. Disabling of protective systems 10. Maintenance of plant equipment and instrumentation 11. Isolation procedures for maintenance 12. Control of plant and process modification 13. Information for authorities and public 14. Planning for emergencies The lessons of Bhopal [toxic] MIC gas disaster; Scope for expanding global biomonitoring and environmental specimen banking Elsevier, Amsterdam (1997) (pp. 2237–2250) (Sriramachari, 1997)
  26. 26. • Recommendations for prevention: – 1st layer: Immediate technical recommendations – 2nd layer: Recommendations to avoid the hazards – 3rd layer: Recommendations to improve management systems. Event Recommendations for prevention Public concern compelled other companies to improve standards Provide information sheet will help public keep risks in perspective Emergency not handled well Provide and practice emergency plans About 2000 people killed Control building factories near major hazards The lessons of Bhopal [toxic] MIC gas disaster; Scope for expanding global biomonitoring and environmental specimen banking
  27. 27. • • • • • • • • • • • Multiple aims of patient care, detoxification and medico-legal issues The importance of clinical pathology and toxicology The need for cumulative study and analyses of each and all ‘on-site accidents’ Studies and collection of data and samples from sporadic severely and moderately ill patients and controls Detailed information of associated chemicals, record of chemical-induced deaths and sickness on site Clinical toxicology of patients exposed to chemicals Clinicopathological guidelines Clinical illustrations and x-rays Continuing studies of individuals at risk Long-term follow-up studies Clinical biochemistry Post-mortem or autopsy studies Background paper on Pathology—Collection, Processing and Storage of Pathological Material for Immediate Analysis and Later Study of Toxicological Effects and their long-term Implication (Sriramachari, 1989)
  28. 28. • • • • • • • • • • • • • • Photographs for identification of victims Forensic examination of the body X-ray records Detailed autopsies of victims Late autopsies amongst exposees Histopathology Light and electron microscopy Routine and special staining procedures Immuno-histochemistry and immunological studies Biochemical analysis of biological fluids and tissue samples Teratogenic and mutagenic studies Experimental studies and animal tissues Detoxification measures Establishing the ‘biochemical lesion’ Background paper on Pathology—Collection, Processing and Storage of Pathological Material for Immediate Analysis and Later Study of Toxicological Effects and their long-term Implication (Sriramachari, 1989)