bhopal 20 yrs later

8/3/2019 Bhopal 20 Yrs Later

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The Accident in Bhopal:

Observations 20 Years Later

Ronald J. Willey, Northeastern University, Boston, MA,[email protected]

Dennis C. Hendershot, Chilworth Technology Inc., Plainsboro,

NJ, [email protected] Berger, CCPS Director, AIChE, New York, NY,

[email protected]



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 SafetyCommittee must keep the memory of

this accident alive



A chemical plant in

Bhopal, India

producing a

pesticidetradename Sevin

So ± What Happened?

Bhopal

from C&E News, 1985



Map of Bhopal

Map reprinted from C & E News Vol 63 (7), p 17, 1985



Bhopal Railroad Station

4 December 2004



Upper Lake Adjacent to the City



Plant Entrance Early 1985

Wil Lepkowski photographer, from C&E News, 1985



1-NAPHTHYL-N-METHYLCARBAMATE

(CARBARYL OR TRADE NAME SEVIN

®

)

METHYLISOCYANATE

AND

ENAPHTHOL

TO

O

O-CNHCH3



AN INTERMEDIATE IN THE

PROCESS

METHYL ISOCYANATE,

MICCH3-N=C=O



Relevant Properties

PROPERTIES of MIC BOILING POINT 39.1°C

VAPOR PRESS AT 20°C 348 mm HG

MOLECULAR WEIGHT 57 VAPOR DENSITY (Rel to Air) 2



METHYL ISOCYANATE

MIC

IS AN EXTREME TOXINHAS A TLV-TWA OF 0.02

PPM

(ONE OF THE LOWEST!)

LC50 of 5 PPM FOR RATS



Storage of MIC

Stored three-41 ton storage

tanks.

One of these tanks became

contaminated with water

resulting in overheating A runaway reaction



Over view Visual of the Storage

Tanks

Adapted from Chemical Week/November 26, 1986 p 8.

Original Source: Union Carbide



Tank 610 Over Pressurized

Adapted from Chemical Week/November 26, 1986 p 8.

Original Source: Union Carbide



Piping at the Top of a Storage

Tank

Relief Valve

Adapted from A. S. Kalelkar in I. Chem.E. Symposium Series No. 110The Institution of Chemical Engineers 1988, p 575, Figure 7

Top of Tank



Relief Valve Opened as Designed

Relief Valve

Adapted from Ibid



Downstream Relief System

CAUSTIC

RVVH

PVH

KNOCK

OUT DRUM

VENT GAS SCRUBBER SYSTEM

ROUTE OF GAS

TOATMOSPHERE

FLARE TOWER

VENT GAS SCRUBBER



The release passed across a

scrubber as designed

The release passed through a flaretower as designed



Unfortunately, neither of these

mitigating units were operating at

the time of the release

One of the largest man-madereleases of a toxin followed



Escaping

Gas

BlanketedMuch of

Bhopal

Map reprinted from C & E News Vol 63 (7), p 17, 1985



As a result«

Gaseous methyl isocyanate entered theenvironment which had very stableatmospheric conditions

The plume formed was heavier than air and dispersed little as it flowed towardspopulation centers

Over 200,000 humans were exposed tomethyl isocyanate.

Over 10,000 deaths occurred



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



TWO MAJOR EXPLANATIONS

1. WATER ACCIDENTLY ENTERED

TANK THROUGH A WATER

FLUSHING OPERATION

2. SABOTAGE



The Water Washing Theory

Original Diagram is from ASK Fig 4



Overview of the Entire the

Process Vent and Relief Vent Lines

Adapted from ASK figure 3



Sabotage Theory

WATER INTRODUCED

TESTIMONY

INDICATED THAT THE

PRESSURE GAUGE

(PRESSUREINDICATOR) WAS

MISSING ON T-610

Adapted from ASK.



Pipe Run 20 years ago



Pipe Run 4 Dec 2004



International Conference on

the 20th Anniversary of theBhopal 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



Presentation by Chief of Police

Swaraj Puri

Described how he was exposed to MIC

vapors

Risked his life seeking answers in thedark night to manage the chaos of

evacuation.

Obtained medical help for the victims,and eventually oversaw the removal

and disposal of bodies.



Poor communications

Less than 10,000 telephones for

900,000 residents at the time.

Hampered the discovery of what wasaffecting the multitudes



Presentation from a Plant

Operator Workers prided themselves working atthe plant.

However, change was underway, drivenby UC India decision to close itsBhopal operations.

Pressure to eliminate costs resulted in

personnel layoffs, and decisionsmentioned above compromised whatcould have been a safely run plant.



Additionally,

Other speakers discussed the long-

term health effects, and epidemiologystudies and monitoring of the long term

health impacts of the disaster haveunexpectedly ceased.

Finally, many papers related to process

safety and how this accident influencedprocess safety practice across theworld were presented.



Conditions we found at the plant

site



The plant operator



Tank 610



Top of Tank 611Relief Valve for

Tank



Filter Area up Close

Filter area

valve to process vent header



Valve Connecting to Vent Header

Stem is inClosed Position



End of pipe rack where jumper

pipe was located



The Scrubber



The Flare Tower



The Control Room



Sign

Inside

the

Control

Room



Close up of the sign details



Other environmental concerns

presence of mercury droplets

Mercury Droplet~1 INCH



A corroded tank whose contents

are unknown



Observations

The Bhopal disaster began long

before the actual event, and its

effects continue today, twenty-oneyears later.

It is clear today that the initiating

event is basically irrelevant.



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 beensaved.



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.



The Root Cause Extends

Beyond Local ManagementDecisions

Optimistic market-size

expectations led to an oversizedplant by a factor of three

Failure of state and local

government to control growth near the plant



Consequences extend well

beyond December 3, 1984

Thousands of people injured that day

continue to suffer

And, because Union Carbide wasbanished so abruptly from the site, the

chemicals remaining on site were never

properly removed

This has lead to additional significantenvironmental and health impacts



Serious accidents are not

common It is easy to fall into the mindset that

they cannot happen.

This is a common human failing, and itexplains many risky behaviors from

driving too fast on the highway to

failure to maintain critical safetysystems in a chemical plant.



Bhopal clearly disproves this

In no circumstances does ³unlikely´

mean ³impossible,´

Some possible consequences areclearly so significant that ³unlikely´

still leaves one with unacceptable risk

that must be addressed more

aggressively.



A Silver Lining

Bhopal has lead to improved process safetypractices

AIChE¶s Safety and Health Division and

Center for Chemical Process Safety, andthroughout many other organizations aroundthe world.

Fundamental principles such as Managementof Change, Mechanical Integrity, HazardAnalysis, and Layers of Protection are now inthe toolbox of most practicing chemicalengineers around the world.



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 preventfuture Bhopals.



Conclusions

Every business decision has

safety consequences.

A negative safety outcome is anegative business outcome.

In order to do the right thing,

politics and the local communitymust be assessed, understood,

and protected.



Questions???

bhopal 20 yrs later

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