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Man ag in g LNG Risk s:Separa t ing t h e Fact s
f r om t h e My t h s
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A u t h o r s
Dr. G. A. Melhem ([email protected]),
Dr. A. S. Kalelkar ([email protected]),
Dr. S. Saraf, ([email protected]),
and Henry Ozog ([email protected])
ioMosa ic Corpor a t ion Hous ton Of f ice
2650 Fountain View Drive, Suite 410,
Houston, Texas 77057
Tel: 713-490-5220
Fax: 832-553-7283
ioMosa ic Corpor a t ion Headqu ar t ers
93 Stiles Road,
Salem, New Hampshire, 03079.
Tel: 603-893-7009
Fax: 603-251-8384
Managing LNG Risks: Separa t ing t he Facts f rom th e Myths
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Facts and Myt hs
Some parts of the US media have managed to dramatize key issues
surrounding LNG transportation, facility operations, and proposed new
projects. Erroneous media speculation and sensationalism, especially
regarding the threat of terrorism, have created an atmosphere of anti-LNG
sentiment fueled by fear and paranoia.
The media are partly influenced by erroneous, so-called independent expert
analysis and public statements. This has been exacerbated by political and
public concerns and pressure, skepticism and doubts over recent studies
and statements from LNG companies and government agencies, as well as
historical and recent incidents such as Skikda.
It is becoming very difficult for the average person to separate fact from
fiction because of this sensationalism and the hidden motives and private
agendas of various working groups.
This paper will separate facts from myths regarding statements reported by
various newspapers, working groups, and web sites.
At t rac t iv eness o f LNG Fac i l i t ies and Vesse ls as
Ter ro r i s t Targe ts
After the terrorist attacks of 9/11, government agencies and the public
became more concerned about chemical storage and transportation facilities
that are close to populated areas. Facilities handling large quantities of
hazardous materials, such as LNG terminals and tankers, were initially
identified as attractive terrorist targets.
The scenario feared by all involves a terrorist using an explosive charge (or
flying an airplane) to breach and possibly detonate one or more storage
tanks on a ship containing up to 125,000 m3 of LNG in a heavily populated
area. The same scenario is feared for large LNG storage tanks. As a result,
security and surveillance of LNG terminals/facilities and ships coming to port
to unload LNG cargo have increased considerably.
In 2002, the city of Boston denied permission to an LNG tanker from
entering port and unloading its much needed LNG cargo at an Everett LNG
terminal, during the winter. In addition, there is significant opposition to
Er r oneous med i a
specu la t i on and
sensat iona l i sm,
espec ia l l y regard in g
t h e t h r e a t o f t e r r o r is m ,
have c reated an
a tm os pher e o f an t i -
LNG sent im ent fue led
by f ea r and pa r ano i a .
LNG tank e r s and bu l k
s to r age t ank s a r e no t
a t t r ac t i v e t a r ge t s f o r
t e r r o r i s t s wh o s eek t o ach ieve mass
casual t ies .
Managing LNG Risks: Separa t ing t he Facts f rom th e Myths
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proposals for LNG terminal expansions, and as well as proposals to build
new LNG terminals. The opposition comes from both the general public as
well as politicians. There is a lot of debate surrounding the potential for an
LNG explosion.
Let us examine the issue of possible LNG explosion when the liquid and
vapor are not confined. First, LNG has to be vaporized and then mixed in
the right proportions with air in order to obtain a composition that can burn.
Furthermore, methane is relatively insensitive to initiation as compared to
heavier hydrocarbons. Available data and good understanding of explosion
dynamics indicate that it is not possible to detonate LNG vapors, even with
the use of an explosive charge (that is large enough) on a storage tank,
unless the LNG vapors contain high fractions of ethane and propane (morethan 20%). Explosion test data on methane/ethane mixtures in the vapor
phase support these statements1. The likelihood of this scenario is
equivalent to each of the authors of this paper winning the power ball or
megabucks lottery several times, simultaneously.
The most likely outcome of a terrorist attack will be a large pool fire and
possibly a low order deflagration/flash fire of finely divided LNG liquid
droplets aerosolized by the blast force of the explosive charge. LNG pool fire
hazards are localized and as a result thermal radiation effects (2nd degree
burns) are typically confined to within one or two pool diameters from the
edge of the flame. This significantly limits the extent of impact.
As a result, LNG tankers and bulk storage tanks are not attractive targets
for terrorists who seek to achieve mass casualties.
Unders t and Hazards and Man age Risk
If we only managed hazards, no one would be flying an airplane or driving a
car to work. When we fly or drive we are aware that we could get killed but
we factor in the likelihood of that occurring and it is very low. We should
and do manage risk and not just hazards. The LNG industry has a lower riskprofile than airlines, and chemical and petrochemical processing facilities to
name a few2. Risk is defined as the probability of occurrence of an unwanted
event. Risk has two components, (1) a probabilistic one relating to the
likelihood of occurrence of an event and (2) a deterministic one relating to
the magnitude of the event.
The l ik e l i hood o f t h i s
scenar io i s equ iva lent
t o eac h o f t he au tho r s
o f t h i s paper w i nn i ng
t he pow er ba l l o r
m egabuc k s l o t t e r y
severa l t imes ,
s imul taneous ly .
U l t i ma te l y , it i s a
ques t i on o f wha t r i sk
l eve l i s to le rab le or
acceptab le vs . th e
economic benef i t
der i ved by soc ie ty /
c ommun i t i es .
1 Bull, D.C., and Elsworth, J.E., Susceptibility of Methane/ethane Mixtures to Gaseous Detonations in Air, Combustion and Flame, 35, 87
91, 1979.
2 Arthur D. Little Inc. and SAI Comparison of accident probabilities, 1975
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Ultimately, it is a question of what risk level is tolerable or acceptable vs.
the economic benefit derived by society/communities.
Whether the risk is perceived by society/individuals to be voluntary or
involuntary, risk is also a key factor. The additional risk associated with
smoking or driving a vehicle is a voluntary risk. Additional risk associated
with siting of new facilities is usually considered involuntary risk that can
only be avoided at a great cost, such as moving away from the area.
Involuntary risk is much less tolerable/acceptable than voluntary risk.
Communities are generally intolerant of activities that will be visually
intrusive, noisy, produce offensive odors or are pollution threats. Where risk
is concentrated in a local area, the potential impact of an accident will bevery visible and deeply felt. This is especially true when visible risk is
contrasted with a road accident or disease where one or more isolated
individuals are affected and there is negligible concentration of risk on
communities.
Ironically, society in general will expand greater efforts to reduce visible
risk despite the fact that more lives are lost by other causes.
The magnitude of impact of a potential accident carries a lot of weight. An
accident which has the potential (or is perceived to have the potential) to
injure or kill a large number of people attracts more public interest than the
individual incidents capable of killing or injuring the same number of people.
The likelihood of a scenario leading to the total loss of containment involving
an LNG tanker or a large LNG storage tank must be considered in
conjunction with the potential hazards such events pose and their impact on
the public. US regulations (49 CFR Part 193) require that LNG facilities have
secondary containment for LNG tanks and LNG transfer facilities. In
addition, the facility must maintain exclusion zones to protect the public
from potential thermal radiation and flammable vapor dispersion hazards.
Todays risk assessment methods can be used to establish individual and/or
societal risk profiles or environmental impact. These methods are well
understood and generally accepted by operating companies, the public, and
government.
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