The Accident in Bhopal: Observations 20 Years Later

1
The Accident in Bhopal Observations 20 Years
Later

• Ronald J. Willey, Northeastern University,
  Boston, MA, r.willey_at_neu.edu Dennis C.
  Hendershot, Chilworth Technology Inc.,
  Plainsboro, NJ, dhendershot_at_chilworth.com Scott
  Berger, CCPS Director, AIChE, New York, NY,
  scotb_at_aiche.org

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Introduction

• The most influential process safety accident in
  our history passed its 20th anniversary on Dec 3,
  2004
• This accident occurred before most current
  college students were born
• Educators and the Process Safety Committee must
  keep the memory of this accident alive

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So What Happened?

• A chemical plant in Bhopal, India producing a
  pesticide tradename Sevin

Bhopal
from CE News, 1985
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Map of Bhopal
Map reprinted from C E News Vol 63 (7), p 17,
1985
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Bhopal Railroad Station 4 December 2004
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Upper Lake Adjacent to the City
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Plant Entrance Early 1985
Wil Lepkowski photographer, from CE News, 1985
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(No Transcript)
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AN INTERMEDIATE IN THE PROCESS

• METHYL ISOCYANATE, MIC
• CH3-NCO

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Relevant Properties PROPERTIES of MIC

• BOILING POINT 39.1C
• VAPOR PRESS AT 20C 348 mm HG
• MOLECULAR WEIGHT 57
• VAPOR DENSITY (Rel to Air) 2

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METHYL ISOCYANATEMIC

• IS AN EXTREME TOXIN
• HAS A TLV-TWA OF 0.02 PPM
• (ONE OF THE LOWEST!)
• LC50 of 5 PPM FOR RATS

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Storage of MIC

• Stored three-41 ton storage tanks.
• One of these tanks became contaminated with water
  resulting in overheating
• A runaway reaction

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Overview Visual of the Storage Tanks
Adapted from Chemical Week/November 26, 1986 p 8.
Original Source Union Carbide
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Tank 610 Over Pressurized
Adapted from Chemical Week/November 26, 1986 p 8.
Original Source Union Carbide
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Piping at the Top of a Storage Tank
Relief Valve
Top of Tank
Adapted from A. S. Kalelkar in I. Chem.E.
Symposium Series No. 110 The Institution of
Chemical Engineers 1988, p 575, Figure 7
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Relief Valve Opened as Designed
Relief Valve
Adapted from Ibid
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Downstream Relief System
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• The release passed across a scrubber as designed
• The release passed through a flare tower as
  designed

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• Unfortunately, neither of these mitigating units
  were operating at the time of the release
• One of the largest man-made releases of a toxin
  followed

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Escaping Gas Blanketed Much of Bhopal
Map reprinted from C E News Vol 63 (7), p 17,
1985
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As a result

• Gaseous methyl isocyanate entered the environment
  which had very stable atmospheric conditions
• The plume formed was heavier than air and
  dispersed little as it flowed towards population
  centers
• Over 200,000 humans were exposed to methyl
  isocyanate.
• Over 10,000 deaths occurred

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Time 17 Dec 1984 (photo side credits
Tucci/Liaison)
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TWO MAJOR EXPLANATIONS

• WATER ACCIDENTLY ENTERED TANK THROUGH A WATER
  FLUSHING OPERATION
• SABOTAGE

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The Water Washing Theory
Original Diagram is from ASK Fig 4
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Overview of the Entire theProcess Vent and
Relief Vent Lines
Adapted from ASK figure 3
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Sabotage Theory
WATER INTRODUCED TESTIMONY INDICATED THAT THE
PRESSURE GAUGE (PRESSURE INDICATOR) WAS MISSING
ON T-610
Adapted from ASK.
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Pipe Run 20 years ago
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Pipe Run 4 Dec 2004
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International Conference on the 20th Anniversary
of the Bhopal Gas Tragedy

• On December 1 to 3, 2004, Prof. J. Gupta of the
  Indian Institute of Technology Kanpur organized
  this conference in Kanpur, India
• Afterwards, we made an overnight trip by rail to
  the Bhopal site

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Presentation by Chief of Police Swaraj Puri

• Described how he was exposed to MIC vapors
• Risked his life seeking answers in the dark night
  to manage the chaos of evacuation.
• Obtained medical help for the victims, and
  eventually oversaw the removal and disposal of
  bodies.

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Poor communications

• Less than 10,000 telephones for 900,000 residents
  at the time.
• Hampered the discovery of what was affecting the
  multitudes

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Presentation from a Plant Operator

• Workers prided themselves working at the plant.
• However, change was underway, driven by UC India
  decision to close its Bhopal operations.
• Pressure to eliminate costs resulted in personnel
  layoffs, and decisions mentioned above
  compromised what could have been a safely run
  plant.

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Additionally,

• Other speakers discussed the long-term health
  effects, and epidemiology studies and monitoring
  of the long term health impacts of the disaster
  have unexpectedly ceased.
• Finally, many papers related to process safety
  and how this accident influenced process safety
  practice across the world were presented.

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Conditions we found at the plant site
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The plant operator
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Tank 610
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Top of Tank 611
Relief Valve for Tank
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Filter Area up Close
valve to process vent header
Filter area
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Valve Connecting to Vent Header
Stem is in Closed Position
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End of pipe rack where jumper pipe was located
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The Scrubber
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The Flare Tower
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The Control Room
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Sign Insidethe Control Room
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Close up of the sign details
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Other environmental concernspresence of mercury
droplets
Mercury Droplet
1 INCH
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A corroded tank whose contents are unknown
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Observations

• The Bhopal disaster began long before the actual
  event, and its effects continue today, twenty-one
  years later.
• It is clear today that the initiating event is
  basically irrelevant.

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3 Strikes and you are

• If even one of the basic protections functioned
  e.g.
• The refrigeration system
• Or the scrubber,
• Or the flare,
• Many, many lives could have been saved.

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Importance of Communications

• If communications between the plant and corporate
  management had been stronger, and if local
  management had better information and supported
• There may not have been flawed decisions about
  fundamental safety principles.

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The Root Cause Extends Beyond Local Management
Decisions

• Optimistic market-size expectations led to an
  oversized plant by a factor of three
• Failure of state and local government to control
  growth near the plant

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Consequences extend well beyond December 3, 1984

• Thousands of people injured that day continue to
  suffer
• And, because Union Carbide was banished so
  abruptly from the site, the chemicals remaining
  on site were never properly removed
• This has lead to additional significant
  environmental and health impacts

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Serious accidents are not common

• It is easy to fall into the mindset that they
  cannot happen.
• This is a common human failing, and it explains
  many risky behaviors from driving too fast on the
  highway to failure to maintain critical safety
  systems in a chemical plant.

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Bhopal clearly disproves this

• In no circumstances does unlikely mean
  impossible,
• Some possible consequences are clearly so
  significant that unlikely still leaves one with
  unacceptable risk that must be addressed more
  aggressively.

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A Silver Lining

• Bhopal has lead to improved process safety
  practices
• AIChEs Safety and Health Division and Center for
  Chemical Process Safety, and throughout many
  other organizations around the world.
• Fundamental principles such as Management of
  Change, Mechanical Integrity, Hazard Analysis,
  and Layers of Protection are now in the toolbox
  of most practicing chemical engineers around the
  world.

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So

• It would be a stretch to say that an accident
  like Bhopal could never happen today, but as we
  work together to build a global culture of
  process safety, the use of the process safety
  tools and the strength of process safety
  practices will help prevent future Bhopals.

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Conclusions

• Every business decision has safety consequences.
• A negative safety outcome is a negative business
  outcome.
• In order to do the right thing, politics and the
  local community must be assessed, understood, and
  protected.

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Questions???