The case study presented on the one day symposium on
"PREVENTION OF INDUSTRIAL / CHEMICAL DISASTERS
PRESENT DAY CHALLENGES,EMERGING TRENDS AND STRATEGIES”
Date
Place
: 4th December, 2009
: Bangaluru,
Organized by : Department of Factories and Boilers,
Govt. of Karnataka.
CASE STUDIES OF MAJOR CHEMICAL
DISASTERS –SCENARIO
by
Dr. S.MARUTHAPPA, Ph D, FIFireE (UK),
VICE PRESIDENT Safety Engineers Association of (India)
PRESIDENT; Institution of Fire Engineers (UK) Southern , India Chennai
Branch
The various accidents due to these consequences are well
known and gives prominent caution to prepare, practice and
amend the fire/Toxic Disaster Management plans for each
and every hazardous process
As per amended factory Act each chemical industry has to
prepare Disaster Management On site and Off site and
submit plans to chief Inspector of Factories & Boilers for
their approval.
Organizations world wide have learnt the importance
of applying principles of prevention and protection in
chemical industries in hard way.
Each chemical industry aims to achieve totally zero
accident potential.
Therefore prevention, protection and suppression
techniques have been applied to reduce the probability
of disaster.
Some of the worst disaster of toxic gas releases
have occurred in chemical Industries like MIC,
Ammonia, and Chlorine etc.
Some data’s on past planning in detail which
explains the various stages of Disaster Management
plan.
Bhopal,, 1984
Union Carbide had a plant in Bhopal, India, for the
production of insecticide Carbaryl. Methyl iso cyanate was
an intermediate used in the process
On the night of Dec. 2nd and 3rd, 1984, a Union Carbide plant in
Bhopal, India, began leaking.
 Due to run-away reactions, temperature and pressure rose
and the safety valve lifted to the atmosphere.
 25-27 tons of the deadly gas methyl IsoCyanide spread
throughout the city of Bhopal.
 Half a million people were exposed to the gas
 protective systems that should have prevented or minimized
discharge were out of service.
 Refrigeration system to cool the reactor was down.
 Scrubbing system to absorb the released vapor was not
immediately available.
 Flare system to burn vapors getting past the scrubber was out
of service.
Most killed or injured lived in Shanty town that grew up
too close to the plant.
Lessons learned
 Reduce inventory of hazardous material (MIC)
 Keep all the safety related equipment in order
 Keep residential areas away from the plant
 Proper Management
MIC STORAGE SYSTEM
EVACUATION SYSTEM
FLARE SYSTEM WAS
DECOMMISSED DUE TO
CORRODE PIPE
Flixborough, UK, 1974
 Company’s name: NYPRO Ltd.
–
–
–
–
–
–
–
Sudden release of 30 – 50 tonnes of cyclohaxane
Massive explosion
Complete plant destruction
Casualties 28
Injured 36
1821 houses damaged
167 shops and factories damaged half mile away
Flixborough, the process
 6 reactors in parallel used for cyclohexane
oxidation
 The reaction was slow and the conversion was
kept low to prevent formation of byproducts
 Each reactor has a working volume of 20 tonnes
of cyclohexane
Flixborough, the process
 One of the reactors had minor crack which was
detected on time and removed for repair.
 In order to keep the operation going, a pipe was
installed temporarily in the free space of the
removed reactor.
 No engineer involved as the site engineer had left
NYPRO.
Flixborough, UK, 1974
Cracked
reactor
Flixborough, UK, 1974
Flixborough, UK, 1974
 Dogleg pipe
with bellows on
both ends.
 No bellows
calculation.
 No bending
moment
calculation
 Poor scaffold
support
Flixborough, UK, 1974
Plant operated for about two months
The dogleg pipe exposed to continuous stress and
tensions and started to weaken gradually.
Eventually a slight increase in pressure twisted the
pipe and broke it at both ends.
 Huge volume of reactants and products released
and caused a massive explosion
Flixborough, UK, 1974
Flixborough, UK, 1974
 The control room collapsed completely.
 18 people died in the control room.
 Explosion shattered the windows and caused the
roof to collapse
 Some died from flying broken window glasses
and debris
 Some died from roof collapse
Flixborough, UK, 1974
Flixborough, UK, 1974
Flixborough, UK, 1974
CHLORINE PRODUCTION UNITS & CONSUMPTION
CENTRES IN INDIA
Production Units
(Major Merchant)
Consumption Sites
(Excl: Captive
Consumption)
Chlorine Transportation
necessary to cater to widely
spread Cl2 Consumers
D
1
30
INDIAN CHLORINE INDUSTRY

34 CHLOR-ALKALI UNITS SPREAD ACROSS INDIA

WIDE CAPACITY RANGE : VERY SMALL PLANTS OF 30 TPD TO WORLD
SCALE PLANTS OF 750 TPD: -
REGION
TOTAL
CAPACITY
CAPACITY DISTRIBUTION
TPD *
%
EAST :
1021
13.0
WEST :
3698
47.2
NORTH : 1171
15.0
SOUTH :
1943
24.8
•Assuming

8
13
4
9
CAPACITY
RANGE
TPD *
30-365
40-750
235-335
110-375
Plant Operational Period of 350 days per year.
INDIAN CHLORINE » CAPACITY
(2007-08)
NO. OF
PLANTS
: 2.50 mMTPA
» PRODUCTION : 1.95 mMTPA
» CONSUMPTION : 1.95 mMTPA
Chlorine - Overview
• Noncombustible, yellow-green
gas with a pungent, irritating odor
and strong oxidizing effects
• Slightly soluble in water
• Combines with it to form
hypochlorous acid (HClO) and
hydrochloric acid (HCl)
• Highly corrosive action causes
injury when the gas reacts with
moisture in the body
PHYSICO CHEMICAL PROPERTIES OF CHLORINE
Physical state
pressure)
Boiling Point
Sp.gr
Vapour density
kg/m3 Vapour pressure
IDLH
:Liquid (under
Odour threshold
PEL (OSHA)
TLV-STEL (ACGIH)
TLV-TWA (ACGIH)
IDLH (NIOSH, MSHA)
: 0.31 ppm
: 1 ppm
: 3 ppm
: 0.5 ppm
: 2.5 ppm
:-34.6C
:1.56 (Liquid –34.6 C)
:2.49
:5.5 kg/cm2g
:25PPM
Table-1
CHEMICAL PLANT EXPLOSIONS, FIRES, TOXIC
RELEASE OVER 20 – YEARS
HAZARDS FACTORS
INCIDENTS
%
Plan site Problems
16
3.5
Inferior Plant Layout
09
2.0
Poorly Designed Structures
14
3.0
Faulty Material Evaluation
93
20.2
Process Problem
49
10.6
Material Handling Problem
20
4.4
Operational Failure
143
31.1
Weak Safety Programme
37
8.0
460
100.0
COMMON ELEMENTS OF HAZARDOUS
MATERIALS 1. RISK EVALUATION
2.
NOTIFICATION POCEDURES AND
COMMUNICATION
3. ORGANISATIONAL RESPONSIBILITIES
4. EMERGENCY RQUIPMENTS AND FACILITIES
5. PUBLIC EDUCATION AND INFORMATION
6. TRAINING AND PERIODICAL MOCK DRILLS
PREVENTIVE MEASURES
PREVENTION METHOD
IMPLEMENT PROCEDURE
Work Permit Systems
Standard Operating
Inspection Schedules
Maintenance Procedures / Schedules
Maintenance
Identification & Periodic Inspection of Critical
Equipments
Quality Assurance
How to Report Emergency
Emergency Assembly Point
Training
How to Evacuate
Fire Fighting
Training in civil Defense and Rescue Handling
PREVENTION
METHOD
IMPLEMENT PROCEDURE
Protective Equipment
Training
Equipment Shut Down
Excavation
Management of
Chance
Process / Procedural Changes
Hazards by Modification
SCENARIO DESCRIPTION
Toxic gas release, Fire ,& Explosion, are
the major three scenarios which can arise
and lead to a disaster in chemical
industries.
These , release are due to flammable &
toxic gases under abnormal process, and
storage or handling conditions.
The consequences, are flash fire, BLEVE
, UVCE AND Toxic exposure.
Some examples of the toxic gases and its toxicity
are listed below
CHEMICAL
THRESHOLD LIMIT VALUE
(PPM)
AMMONIA
25
CHLORINE
01
BENZENE
10
CO
35
H2S
10
CS2
10
The toxic chemicals like Ammonia, chlorine are
predominant industrial chemicals used in the fertilizer,
chlor alkali, pesticide, pharmaceutical industries etc.
In general these two chemicals are stored in the
pressurized or refrigerated storage.
The boiling points of the Ammonia and chlorine are –
33.4C and –344 C respectively.
From the past histories, it is well clear that the accident
in these storages are more frequent.
The list of few past accidents involving these
chemicals are given in the table. The major causes of
accident are over pressure, line rupture, refrigeration
failure, corrosion, explosion and human error.
Unlike other gases Ammonia and chlorine experiences
different types of dispersion when released to the
atmosphere and depend on the type of storage. If the
gas is stored under normal temperature.,
while flashing the gas will disperse as a
heavy gas and slums until the density of
the gas equals to the atmosphere.
This change in phase of the dispersion
needs special attention in the usage of
dispersion model.
The proper selection and usage of
model for a particular scenario is very
important because this mathematical
model suggests the damage distance for
various concentrations.
Based on this damage distance,
dispersion direction,
exposures time in a particular place
for a given concentration will be the
key areas were the off – site
emergency crew will concentrate for
disaster management.
In a chloro-alkali plant situated in Durgapur, West Bengal there
are four dish-end cylindrical shaped horizontal, thermocool
insulated liquid chlorine storage tanks.
 The storage vessels are made of mild steel sheet of 21-mm
thickness and of overall 12548 mm in length with inside diameter
of 2743 mm.
Around 11 pm on 09.06.87 the process controller started
degassing of one chlorine tank.
It was first noticed the gas nuisance at 12 O' clock at night on
09.06.87 and presumed a leak at the gland. As no one experienced a
bonnet leak before and as light on the spot was not sufficient workers
never thought a leak could be there through body seal of the bonnet.
The release of liquid chlorine through the large hole as the valve
was thrown out of its position gave rise to huge spillage of liquid
chlorine from the tank
The chlorine hydrate so formed will
release acidic vapour for a long time
even after the leakage was stopped.
It was necessary to neutralize the
chlorine hydrate on the floor with
lime water or caustic soda solution
Its toxicity irritates the respiratory system. The initial symptom of
chlorine exposure is suffocation. Severe exposure to the gas may
cause pulmonary edema within 30 to 60 minutes.
Immediate effects
The immediate effects of chlorine gas toxicity include acute
inflammation of the conjunctivae, nose, pharynx, larynx, trachea,
and bronchi.
Irritation of the airway mucosa leads to local edema secondary to
active arterial and capillary hyperemia.
Plasma exudation results in filling the alveoli with edema fluid,
resulting in pulmonary congestion.
Detection of Chlorine Leakage Point
Take a stick with a
cloth bulb at one end.
Soak the cloth bulb
with aqua ammonia
and hold it close to
the area of suspected
leak.
A white cloud will
indicate if there is
any Chlorine leakage
and the source
thereof.
The Chlorine Gas Leak at Jamshedpur
On the afternoon of May 27, the people of Jamshedpur were caught
unaware
. They were exposed to a dense, pale green, pungent and poisonous gas,
Chlorine.
This gas had leaked from an unused cylinder lying in the Tata Motor’s
water treatment plant for the past 10 years.
By the next day, around 150 to 200 people had been hospitalised.
about 60 to 70 residents who reported breathing difficulty were admitted to
the Tata Motors hospital in Jamshedpur
Other Incidents of Chlorine Leak
Villagers fall ill following chlorine leak
Mumbai Twelve villagers from Kathai, Dhondi and Talodi villages in
Bhiwandi were admitted to the Indira Gandhi Memorial Hospital on
Thursday afternoon after they complained of burning eyes, breathing
difficulty, nausea and vomiting out blood.
 “In 1987, a water purification plant was being run by the Maharashtra
where Twelve villagers were admitted to the Hospital after they
complained of burning eyes, breathing difficulty, nausea and vomiting
out blood.
 Preliminary investigations have revealed that the above were the
effects of a chlorine leak from four abandoned chlorine cylinders, which
were used for water purification two decades back.
SPIC ammonia unit shut due to leakage problem
Southern Petrochemical Industries
Corporation (SPIC) at Tuticorin has been shut
down due to a leakage in the pipeline. When
the repair works were going on, a fatal
accident occurred on October 1, company
sources told that after the southern grid failure
last month, technical problems arose in
SPIC's plant, causing a leakage in the
pipeline.
While trying to do the repair work, Joint
Manager (Operations) slipped and fell. The
gas mask he was wearing came off and he
died of asphyxiation, it is learnt.
CASE STUDY
AMMONIA RELEASE
On 26 th August 1992 at a Fertilizer Factory
Ammonia gas leaked through a faulty value and
got exploded,
killing 11 workers and made another 10
seriously ill., this accident accrued in the urea
plant while a team of since 25 workers and
officials were working on the maintenance of
ammonia pump in the plant.
The leaked gas immediately engulfed as
maintenance of an ammonia pump in the plant.
Mangalore Chemicals and Fertilizers
Limited
There was a chemical accident in the Urea Plant
at M/s. Mangalore Chemicals and Fertilizers
Limited, Panambur, Mangalore on 9.2.2000.
An 8" dia high pressure pipe line housing a
weldolet was connected between autoclave (urea
reactor) of 108MT capacity and the stripper to
carry ammonium carbamate (Urea Solution).
The pressure of pipe line was of the order of
141kg/cm2 and the temperature of 180 C. The
Solution had contained 29% of ammonia, 18%
carbon di oxide and 32% of urea.
Chlorine Leakage Management
 Take immediate steps to mitigate the situation as soon as
there is any indication of presence of Chlorine in the air.
 Chlorine leaks always get worse, if not attended promptly.
 Since gaseous Chlorine is 2½ times heavier than air, it
tends to lie close to the ground.
WATER SHOULD NEVER BE SPRAYED ON A
CHLORINE LEAK.
On 9th February 2000, a substantial quantity of ammonium
carbamate solution leakage was noticed at the weldolet joint of
the pipeline
weld let used in the high pressure pipe line had high
carbon content which is not suggested for that kind of a
process,
 maintenance/repair works was undertaken on line even
after noticing the hazardous solution which amounts of
non implementation of shutting down procedures
envisaged in the on site emergency plan
. Further the high-pressure pipeline was not subjected to
hydrostatic test, ultrasonic tests and examinations as
required under relevant provisions of law for its
soundness.
The personnel who were on the job were not wearing
any personal protective equipment in addition to nonadherence to work to permit system.
The leaked gas immediately engulfed as maintenance of an
ammonia pump in the plant. water was sprayed all over the
dispersed area. People in the dispersed direction got
evacuated.
The leaked gas immediately engulfed as area over 50 m, .
Consequent to which, 8 persons were affected amongst
them 2 died on the spot and the other two at the hospital
amounting to death of 4 persons including the
maintenance manager and an engineer.
The plant was immediately shut down.
National Fertilisers Limited (NFL) at Panipat.
IT WAS a routine job of replacing
the defective safety valve of the
spare ammonia feed pump at the
15-year-old urea plant of the
National Fertilisers Limited (NFL) at
Panipat.
 Around 11.00 am on August 26,
eight employees climbed the steps
to the open-air ramp, and began to
replace the valve when the
unthinkable happened.
The bush of the suction valve that stops the gas flow from
the mainline, gave way. Liquid ammonia burst out at the high
pressure of 23 kg per sq cm, vapourising within seconds to
form suffocating clouds of deadly gas.
 This hit and choked to death eleven persons and injured ten
even as their colleagues sprung into action to diffuse the gas
with water sprays.
But just 36 hours after the accident, the plant had begun work again.
Clearly, many questions about the disaster remain.
Panipat may have opened up a can of worms about the lack of safety
regulators, and even more importantly, preventive maintenance Indian
industry continues to suffer.
PHYSICO CHEMICAL PROPERTIES OF AMMONIA
Physical State
: LIQUID (Under Pressure)
Boiling Point
: -33.3 0 C
Vapour pressure
: 10 bar (at room temp)
Vapour Density
: 0.6 kg/m3
Explosive limits
: 15% - 29% (by volume in air)
Threshold Limits Value (TLV) : 25PPM
TOXICITY OF AMMONIA AT DIFFERENT
CONCENTRATIONS
AMMONIA
(PPM)
TOXIC EFFECT
EXPLOSURE
DURATION
25
Odor detectable by most persons
For eight hours exposure
50
No adverse effect
For eight hours exposure
100
No adverse effect for average
workers
Deliberating exposure for
long duration not
advisable.
400
Immediate nose and throat
irritation
No serious effect for 30 to
60 mins
700
Immediate eye irritation
-Do-
1700
Convulsive coughing severe eye,
nose and throat irritation.
Could be fatal after 30
mins
2000-5000
Causes burns blister
strangulation asphyxia & ultimate
death
Could be fatal after 15
mins
5000-10000
Respiratory spasm rapid asphyxia
Fatal within mins
DAMAGE DISTANCE
The damage distance of the Ammonia release has been
estimated according to the quantity of the hazard release
and mode of release (Puff or Pluma Type). The dispersion
of the released material depends on the various parameters
like
• Wind direction
• Wind velocity
• Atmosphere stability conditions
• Surface roughness
• Process parameters of the material released like
1. Pressure
2. Temperature.
3. Density
• Reactivity.
• Humidity
Using the above parameters the affected area under IDLN
concentration have to be calculated and interpolating the
population density areas will highlight the probability of
lethality / toxic exposure of people / animals etc in
particular location.
This will be very useful to the emergency action team to
evacuate to provide personnel protective appliances and
equipment to take remedial action on the off-site.
SCENE OF DISASTER
Wind - direction
GREEN BELT AREA
ON SITE
GREEN BELT
(500 MTS)
4. EMERGENCY ACTION
On- site emergency:
The emergency situation arising with in the plant
premises is called on-site emergency.
The effects of the disaster are with the plant and the
management of such disaster and its effect are
called on-site emergency management plan.
On – Site Organisation chart
Office
Ph.No
Chief Co-ordinator
Name
Residence
Ph.No
Plant Coordinator
Name
Fire & Safety
Coordinator Name
Engineering
Coordinator Name
Welfare & Media
Coordinator Name
Residence Ph.No
Office
Ph.No
Residence Ph.No
Office
Ph.No
Residence Ph.No
Office
Ph.No
Residence Ph.No
Office
Ph.No
Communication
Coordinator Name
Medical
Coordinator Name
Transport & Security
Coordinator Name
Materials
Coordinator Name
Residence Ph.No
Office
Ph.No
Residence Ph.No
Office
Ph.No
Residence Ph.No
Office
Ph.No
Residence Ph.No
Office
Ph.No
Residence
Ph.No
Finance
Coordinator
Name
Chart - 1
Office Ph.No
On – Site Succession chart Coordinators
Office
Ph.No
Chief Co-ordinator
Name
Residence
Ph.No
Plant Coordinator
Name
Fire & Safety
Coordinator Name
Engineering
Coordinator Name
Welfare & Media
Coordinator Name
Residence Ph.No
Office
Ph.No
Residence Ph.No
Office
Ph.No
Residence Ph.No
Office
Ph.No
Residence Ph.No
Office
Ph.No
Communication
Coordinator Name
Medical
Coordinator Name
Residence Ph.No
Office
Ph.No
Residence Ph.No
Office
Ph.No
Residence
Ph.No
Transport & Security
Coordinator Secretary
Name
Residence Ph.No
Office
Ph.No
Finance
Coordinator
Name
Chart - 2
Office Ph.No
Materials
Coordinator Name
Residence Ph.No
Office
Ph.No
Off-site emergency:
The emergency situation arising in plant escalates and
spreads beyond the compounded wall is called Off-site
emergency.
Disaster, which can effect more then few kilometers like
toxic dispersion, vapour cloud explosion, flash fire, BLEVE
are the typical examples.
For off-site and on –site emergency situation are tackled
buy different organizations with – in and out side the plant.
Each organization is assigned with specific jobs or
responsibilities during emergency situations.
Residence
Ph.No
CMD
Office
Ph.No
PS to CMD
Chief / Home
Secretary
Govt of State
Ph.No
Director
Civil Defence
Ph.No
CONCERNED
Ministry / Occ
New Delhi
Ph.No
Chief / Home
Secretary
Govt of State
Ph.No
State Pollution
Control Board
Ph.No
Oil Industry
Safety
Directorate
Ph.No
District
Collector
Ph.No
Director of
Fire Services
Ph.No
Phone numbers of Neighbor Industries
1.-----------------2.-----------------Chart - 3
CONCLUSIONS
We learn best through our own
experiences in different phases of our
life.
Mistakes could be catastrophic in a
chemical plant, but it is a great
opportunity to learn and design a safer
plant in the future.
We must learn from previous
incidents and develop new procedures,
practices and management systems.
These incidents have much learning
which reveal many hidden facts about
safety and provide efficient tools for
prevention of similar incidents in the
future.
Any Questions ?
Maru Associates