Lecture 1

Safety Practices in Chemical and

Nuclear Industries

Review of Industrial Accidents

Dr. Raghuram Chetty

Department of Chemical Engineering
Indian Institute of Technology Madras
Chennai- 600 036.
 Definitions

Safety
The condition of being safe; freedom from danger, risk or
injury.

Reliability
The probability that a component part, equipment, or system
will satisfactorily perform its intended function under the
given circumstances for a specified period of time.
Major Oil Industry Accidents

 July 6, 1988: Piper Alpha disaster. An explosion and

resulting fire on a North Sea oil production platform.

 Total insured loss is about US$ 3.4 billion. Rated as the

world's worst offshore oil disaster in terms both of lives
lost and impact to industry.

 167 men were confirmed dead.

Major Oil Industry Accidents
 March 23, 2005: Texas City Refinery explosion. An
explosion occurred at a British Petroleum refinery in
Texas.
 It is the third largest refinery in the United States and one
of the largest in the world, processing 433,000 barrels of
crude oil per day and accounting for 3% of that nation's
gasoline supply.
 Over 100 were injured, and 15 were confirmed dead.
 Several level indicators failed, leading to overfilling of a
drum, and light hydrocarbons concentrated at ground
level throughout the area. A nearby running diesel truck
set off the explosion.
Major Oil Industry Accidents

 December 11, 2005: Hertfordshire Oil Storage Terminal

fire.
 A series of explosions at the Buncefield oil storage depot,
described as the largest peacetime explosion in Europe,
devastated the terminal and many surrounding
properties.
 There were no fatalities. Total damages have been
forecast as £750 million.
Major Oil Industry Accidents
 April 20, 2010: The Deepwater Horizon oil spill (BP oil
spill) in the Gulf of Mexico flowed for three months.

 It is the largest accidental marine oil spill in the history of

the petroleum industry.

 The explosion killed 11 men working on the platform and

injured 17 others. About 4.9 million barrels of crude oil
was released into the sea.
BP Oil Spill Gulf Mexico

Image courtesy: Google Images

12 Killed in IOCL October 29, 2009.
The Burning Indian Oil Corporation depot

Image courtesy: Google Images

IOCL fire due to negligence
Major Chemical Industry Accidents

 June 1, 1974: Flixborough disaster, England. An

explosion at a chemical plant near the village of
Flixborough kills 28 people and seriously injures another
36.

 July 10, 1976: Seveso disaster, in Seveso, Italy, in a

small chemical manufacturing plant, due to the release of
dioxins into the atmosphere, 3,000 pets and farm animals
died and, later, 70,000 animals were slaughtered to
prevent dioxins from entering the food chain.
Major Chemical Industry Accidents
 In addition, 193 people in the affected areas suffered from
chloracne and other symptoms. The disaster lead to the
Seveso directive, which was issued by the European
Community and imposed much harsher industrial
regulations.
 November 19, 1984: San Juanico, Mexico LPG Disaster,
a gas leak in stored LPG set off a gas cloud which drifted
towards houses, ignited and caused BLEVE, rupturing
large spheres and many cylinders 500 deaths, unknown
number of burn victims
 Major Chemical Industry Accidents

 December 3, 1984: The Bhopal disaster in India is the

Worst and Largest industrial disaster on record. A faulty
tank containing poisonous methyl isocyanate leaked at a
Union Carbide plant and left nearly 4,000 people dead on
the first night of the gas leak and at least 15,000 later from
related illnesses. The disaster caused the region's human
and animal populations severe health problems to the
present.
 October 23, 1989: Phillips Disaster. Explosion and fire
killed 23 and injured 314 in Pasadena, Texas. Capital
losses over $715 million.
 Bhopal - India
 Bhopal is the capital of a less developed
Madhya Pradesh

 70’s period of green revolution – large scale

use of fertilizers & pesticides

 Import of pesticides costly, indigenous

production encouraged

 Incentives for industrial development

 1969 - UCIL subsidiary of UCC set up

pesticide plant to make Carbaryl in using
imported raw materials

 1979 – granted licence to make MIC based

pesticides

 1980 – production started

Union Carbide
Refrigeration Unit
Vent Gas Scrubber
Flare Tower
Water Curtain
Alarm Siren
Methyl Isocyanate Storage Tank
Bhopal - the World's Worst Industrial Disaster

 The Bhopal disaster, also known as the Union Carbide

disaster or the Bhopal gas tragedy, was an industrial
catastrophe that took place at a Union Carbide pesticide
plant in Bhopal on December 3, 1984.

 Around 12 a.m. the plant released 40 tons of methyl

isocyanate (MIC) gas and other toxins, resulting in the
exposure of over 500,000 people.
Bhopal - the World's Worst Industrial Disaster
 Estimates vary on the death toll. The government has
confirmed a total of 4000 deaths related to the gas
release.

 Other government agencies estimate 15,000 deaths.

Others estimate 8000 to 10,000 died within 72 hours
and 25,000 have since died from gas-related diseases.
Bhopal - the World's Worst Industrial Disaster
 25 years after the gas leak, 390 tonnes of toxic chemicals
abandoned at the Union Carbide plant continue to leak
and pollute the groundwater.

 There are currently civil and criminal cases related to the

disaster ongoing in the United States District Court, the
District Court of Bhopal, against Union Carbide, now
owned by Dow Chemical Company, with an Indian arrest
warrant pending against Warren Anderson, CEO of Union
Carbide at the time of the disaster.
Lethal Dose Comparison

Lethal Dose, ppm Chemical

50.0 Carbon Monoxide

25.0 Chloroform

10.0 Methyl amine

10.0 Benzene

10.0 Acetic acid

10.0 Cyanogen

0.10 Phosgene

0.02 MIC
Bhopal Industrial Disaster

Image courtesy: Google Images

Bhopal Disaster
Areas affected by MIC release
A vast stock of MIC provoked by ingress
of water unleashed a furious gas cloud on
unsuspecting people, at midnight
“A Sleeping community outside
as the gas began its spread. Bodies
roused, coughing, crying out, eyes
burning and watering. Thousands
running, staggering through alleys, many
clutching their babies, not knowing where
to run, which way to escape. Death by the
thousands, injuries by the tens of
thousands. Pandemonium in the hospital.
By daybreak the scene of silence around
those left behind: Fathers, mothers,
children, cows, bulls, goats, dogs – all in
final repose. A peace in its eeriness never
before more heart wrenching. Mass
cremations, mass burials”.
-Wil Lepkowski, C & EN News,1985.
Flixborough Disaster, England

 The chemical plant in operation since 1967, produced

caprolactam, a precursor chemical used in the
manufacture of nylon.
 The process involved oxidation of cyclohexane with air in
a series of six reactors to produce a mixture of
cyclohexanol and cyclohexanone.
 Two months prior to the explosion, a crack was
discovered in the number 5 reactor. It was decided to
install a temporary 50 cm diameter pipe to bypass the
leaking reactor to allow continued operation of the plant
while repairs were made.
Flixborough Disaster, England
 At 17:00 hrs on Saturday 1 June 1974, the temporary
bypass pipe (containing cyclohexane at 150°C and 1 MPa
(10 Bar)) ruptured, possibly as a result of a fire on a
nearby pipe which had been burning for nearly an hour.
Within a minute, about 40 tons of the plant's 400 tons
store of cyclohexane leaked from the pipe and formed a
vapour cloud 100–200 meters in diameter. The cloud, on
coming in contact with an ignition source (probably a
furnace at a nearby hydrogen production plant) exploded,
completely destroying the plant.
Flixborough Disaster, England
 Around 1,800 buildings within a mile radius of the site
were damaged.

 Observers have said that had the explosion occurred on

a weekday, more than 500 plant employees would likely
have been killed. Resulting fires raged in the area for
over 10 days.
 Flixborough Disaster, England

A failure of a temporary pipe section replacing reactor 5 caused

the Flixborough accident
 Flixborough Disaster

Image courtesy:
Google Images
Seveso disaster, Italy

 The Seveso disaster was an industrial accident that

occurred on July 10, 1976, in a small chemical
manufacturing plant (ICMESA) near Milan in Italy. It
resulted in the highest known exposure to 2,3,7,8-
tetrachlorodibenzo-p-dioxin (TCDD) in residential
populations.
Seveso disaster, Italy
 Trichlorophenol was intended as an intermediate for the
herbicide 2,4,5-T (2,4,5-trichlorophenoxyacetic acid).

 This reaction must be carried at a temperature above that

of the normal process utilities that were available, so the
exhaust steam from onsite the electricity turbine was
passed around an external heating coil of the reactor. The
exhaust steam was at 12 bar and 190°C, resulting in a
reaction mixture at 158°C.
 Seveso disaster, Italy

 The plant was supposed to shutdown over the weekend,

and parts of the site started to close down as batches
finished. This caused the load on the turbine to fall
dramatically, resulting in the exhaust steam temperature
rising to around 300°C, heating the reactor wall to the same
temperature.

 The relief valve eventually opened, and about 6 tonnes of

chemicals were released into the air. The accident was not
immediately noticed. No one was at the plant when it
happened.
Seveso disaster, Italy
 The first sign of health problems, burn-like skin lesions,
appeared on children a few hours after the accident.
Latter a severe skin disorder usually associated with
dioxin, broke out on some of the people most exposed to
the cloud.

 Authorities began an investigation five days after the

accident, when animals such as rabbits began to die en
masse. Roughly 70,000 animals -- were killed to prevent
contamination from filtering up the food chain.
Seveso disaster, Italy

Zone A: >50 µg/m2

Zone B: 5-50 µg/m2
Zone R: <5 µg/m2

Image courtesy: Google Images

The Mexico LPG Disaster
 LPG disaster in San Juanico, Mexico city
 19 Nov 1984 (2 weeks before the Bhopal tragedy)

Image courtesy:
Google Images
Storage Tanks

Image courtesy: Google Images

 CISRA
Image courtesy: Google Images
Image courtesy: GoogleCISRA
Images
 CISRA
Image courtesy: Google Images
Damage Contours of Mexico

100m
Sphere
Fragments
200m

300m
Bullets
Phillips Disaster, Texas
 The facility produced high-density polyethylene (HDPE), a
plastic material used to make milk bottles and other
containers.
 The Houston Chemical Complex (HCC) facility employed
905 company employees and approximately 600 daily
contract employees, who were engaged primarily in
regular maintenance activities and new plant construction.
 The incident started at approximately 1:00 PM local time
on October 23, 1989, at Pasadena, Texas. A massive and
devastating explosion and fire ripped through the Phillips
HCC, killing 23 persons and injuring 314.
Phillips Disaster, Texas
 The explosion affected all facilities within the complex,
causing $715.5 million worth of damage plus an
additional business disruption loss estimated at $700
million.

 The initial explosion was equivalent to an earthquake

registering 3.5 on the Richter Scale and threw debris as
far away as six miles.
Phillips Disaster, Texas
 The accident resulted from a release of extremely
flammable process gases that occurred during regular
maintenance operations on one of the plant's
polyethylene reactors.
 More than 85,000 pounds of highly flammable gases
were released through an open valve. A vapor cloud
formed and traveled rapidly through the polyethylene
plant. Within 90-120 seconds, the vapor cloud came into
contact with an ignition source and exploded with the
force of 2.4 tons of TNT.
Phillips Disaster, 1989

Image courtesy: Google Images

SAFETY