domingo, 25 de diciembre de 2011

Peligros del LNG

 Muy a tener en cuenta

Liquified Natural Gas
Natural gas can be sent by pipeline over long distances. For a price, it can be
piped from North Sea platforms to the British mainland, from Algeria to Italy,
or from Siberia to Western Europe. But pipelines are not a feasible way to
send gas across major oceans—for example, from the Mideast or Indonesia to
the United States. A high-technology way to transport natural gas overseas
has, however, been developed in the past few decades, using the techniques of
cryogenics—the science of extremely low temperatures.
In this method, a sort of giant refrigerator, costing more than a billion dollars,
chills a vast amount of gas until it condenses into a colorless, odorless liquid
at a temperature of two hundred sixty degrees Fahrenheit below zero.
This liquefied natural gas (LNG) has a volume six hundred twenty times
smaller than the original gas. The intensely cold LNG is then transported at
approximately atmospheric pressure in special, heavily insulated cryogenic
tankers—the costliest non-military seagoing vessels in the world—to a marine
terminal, where it is stored in insulated tanks. When needed, it can then be
piped to an adjacent gasification plant—nearly as complex and costly as the liquefaction
plant—where it is boiled back into gas and distributed to customers
by pipeline just like wellhead gas.
Approximately sixty smaller plants in North America also liquefy and store
domestic natural gas as a convenient way of increasing their storage capacity
for winter peak demands which could otherwise exceed the capacity of trunk
pipeline supplying the area. This type of local storage to augment peak supplies
is called “peak-shaving.” Such plants can be sited anywhere gas is available
in bulk; they need have nothing to do with marine LNG tankers.
LNG is less than half as dense as water, so a cubic meter of LNG (the usual
unit of measure) weighs just over half a ton.1 LNG contains about thirty per-
Chapter Eight
Liquified Natural Gas
The notes for Chapter 8 appear on page 355 of this pdf.
88 Disasters Waiting to Happen
cent less energy per cubic meter than oil, but is potentially far more hazardous.2
Burning oil cannot spread very far on land or water, but a cubic meter of
spilled LNG rapidly boils into about six hundred twenty cubic meters of pure
natural gas, which in turn mixes with surrounding air. Mixtures of between
about five and fourteen percent natural gas in air are flammable. Thus a single
cubic meter of spilled LNG can make up to twelve thousand four hundred
cubic meters of flammable gas-air mixture. A single modern LNG tanker typically
holds one hundred twenty-five thousand cubic meters of LNG, equivalent
to twenty-seven hundred million cubic feet of natural gas. That gas can
form between about twenty and fifty billion cubic feet of flammable gas-air
mixture—several hundred times the volume of the Great Pyramid of Cheops.
About nine percent of such a tankerload of LNG will probably, if spilled
onto water, boil to gas in about five minutes.3 (It does not matter how cold the
water is; it will be at least two hundred twenty-eight Fahrenheit degrees hotter
than the LNG, which it will therefore cause to boil violently.) The resulting
gas, however, will be so cold that it will still be denser than air. It will
therefore flow in a cloud or plume along the surface until it reaches an ignition
source. Such a plume might extend at least three miles downwind from a
large tanker spill within ten to twenty minutes.4 It might ultimately reach
much farther—perhaps six to twelve miles.5 If not ignited, the gas is asphyxiating.
If ignited, it will burn to completion with a turbulent diffusion flame
reminiscent of the 1937 Hindenberg disaster but about a hundred times as big.
Such a fireball would burn everything within it, and by its radiant heat would
cause third-degree burns and start fires a mile or two away.6 An LNG fireball
can blow through a city, creating “a very large number of ignitions and explosions
across a wide area. No present or foreseeable equipment can put out a
very large [LNG]... fire.”7 The energy content of a single standard LNG
tanker (one hundred twenty-five thousand cubic meters) is equivalent to
seven-tenths of a megaton of TNT, or about fifty-five Hiroshima bombs.
A further hazard of LNG is that its extreme cold causes most metals to
become brittle and contract violently. If LNG spills onto ordinary metals (that
is, those not specially alloyed for such low temperatures), such as the deck
plating of a ship, it often causes instant brittle fractures. Thus failure of the
special cryogenic-alloy membranes which contain the LNG in tanks or
tankers could bring it into contact with ordinary steel—the hull of a ship or the
outer tank of a marine vessel—and cause it to unzip like a banana,8 a risk most
analyses ignore.9 LNG can also seep into earth or into insulation—the cause of
the Staten Island terminal fire that killed forty workers in 1973. Imperfectly
insulated underground LNG tanks, like those at Canvey Island in the
Thames Estuary below London, can even create an expanding zone of perChapter
Eight: Liquified Natural Gas 89
mafrost, requiring the installation of heaters to maintain soil dimensions and
loadbearing properties that are essential to the integrity of the tank.
The potential hazards of LNG are illustrated by the only major LNG spill
so far experienced in the U.S.—in Cleveland in 1944.10 A tank holding four
thousand two hundred cubic meters of LNG, part of America’s first peak-shaving
LNG plant, collapsed. Not all the spillage was contained by dikes and
drains. Escaping vapors quickly ignited, causing a second tank, half as large,
to spill its contents. “The subsequent explosion shot flames more than half a
mile into the air. The temperature in some areas reached three thousand
degrees Fahrenheit.” Secondary fires were started by a rain of LNG-soaked
insulation and drops of burning LNG.11 By the time the eight-alarm fire was
extinguished (impeded by high-voltage lines blocking some streets), one hundred
thirty people were dead, two hundred twenty-five injured, and over seven
million dollars’ worth of property destroyed (in 1944 dollars). An area about a
half-mile on a side was directly affected, within which thirty acres were gutted,
including seventy-nine houses, two factories, and two hundred seventeen cars.
A further thirty-five houses and thirteen factories were partly destroyed.12 The
National Fire Protection Association Newsletter of November 1944 noted that had the
wind been blowing towards the congested part of the area, “an even more devastating
conflagration...could have destroyed a very large part of the East Side.”
It is noteworthy that the plant’s proprietors had taken precautions only
against moderate rates of LNG spillage. They did not think a large, rapid
spillage was possible. “The same assumption is made today in designing dikes”
around LNG facilities.13 The Cleveland plant, like many today, was sited in a
built-up area for convenience; the proximity of other industrial plants, houses,
storm sewers, and so forth was not considered. Less than six thousand three
hundred cubic meters of LNG spilled, mostly on company property, whereas
a modern LNG site may have several tanks, each holding up to ninety-five
thousand cubic meters. And the cascading series of failures in two inner and
two outer tanks was probably caused by a single minor initiating event.14
The future of LNG in the United States is highly uncertain, largely for
economic reasons. LNG shipment requires highly capital-intensive facilities at
both ends and in between. Their coordination is a logistical feat that exposes
companies to major financial risks: “if any of [the system’s components is not
ready on time]...,the entire integrated system collapses.”15 Like the nuclear fuel
cycle, LNG projects require exquisite timing but often do not exhibit it—as
when Malaysia was “caught with finished [LNG] carriers before their fields
and facilities were ready to begin production.”16 This uninsurable financial
exposure by prospective LNG buyers provides a bargaining chip to sellers,
who can simply raise the price and dare the buyers to write off their tankers,
90 Disasters Waiting to Happen
terminals, and regasification plants.
This actually happened in 1980–81. Algeria—the major LNG exporter, and
the sole source of LNG exports to the U.S. during 1979–80—abruptly demanded
that its LNG be priced at the energy equivalent of OPEC oil, more than a
trebling of earlier prices. The U.S. government, which had just negotiated a
much lower gas price with Canada and Mexico, rejected the Algerian demand.
On 1 April 1980, Algeria cut off LNG deliveries to the El Paso Natural Gas
Company, idling its costly tankers and its terminals at Cove Point, Maryland
and Elba Island, Georgia. A third of the Algerian shipments continued to
arrive—via the older (1968–71) Distrigas operation in Everett, Massachusetts,
which uses an oil-linked pricing structure and Algerian-owned ships. But by late
1981, the Cove Point and Elba Island facilities were still sitting as hostages to
price agreement with Algeria. (So was a nearly completed terminal at Lake
Charles, Louisiana.) Algeria has somewhat moderated its initial demands, but
it and other LNG exporters still intend to move rapidly to oil parity. Partly for
this reason, the proposed Point Conception (California) LNG terminal seems
unlikely to be built. Argentina, which has never exported LNG, now proposes
to build a liquefaction plant to ship over eight hundred million dollars’ worth of
LNG per year to the idle Cove Point and Elba Island plants, but market conditions
seem most unfavorable for this project. Acknowledging the bleak economic
outlook, El Paso in February 1981 “wrote off most of the equity ($365.4
million) in its six tankers which hauled Algerian LNG to the East Coast”17—a
sizable loss even for such a large company. Of course the tankers might be
revived under some new price agreement; but the investors would then have no
guarantee that history would not simply repeat itself. Their massive investment
would continue to hold them hostage to demands for higher prices.
The economic difficulties of LNG arise not only in the international marketplace
but also in the domestic one. New, and probably existing, LNG imports
cannot compete with domestic gas (let alone with efficiency improvements and
some renewable options). Recent drilling has vastly expanded the reserves of relatively
cheap domestic natural gas. Recent geological evidence suggests that
enormous reserves can be tapped at prices well below that of imported LNG.
LNG has so far been saleable only by “rolling in” its high price with very cheap
(regulated) domestic gas, so that customers see only an average of the two. Gas
deregulation will probably increase domestic supply and reduce domestic
demand so much further as to squeeze LNG out of the market entirely.
Despite these uncertainties, some LNG is now being imported into the
U.S., and facilities are available for more. Even though the present imports are
only about a thousandth of all U.S. natural gas supplies, they represent a disturbing
vulnerability: not so much in interrupted energy supply as in the damChapter
Eight: Liquified Natural Gas 91
age which the LNG facilities—tankers, terminals, storage tanks, and trucks—
could do to their neighbors.
LNG tankers
Fourteen LNG terminals are operable worldwide. Some are sited in major
urban areas, including Boston Harbor and Tokyo Harbor. (Another, built in
Staten Island, New York, has remained mothballed since its fatal 1973 fire,
though in February 1980 it was proposed that it be completed and used as a
peak-shaving LNG storage facility.) In 1980 the world fleet contained about
eighty specially insulated, double-hulled tankers of several designs.18 Their
average LNG capacity was somewhat over fifty thousand cubic meters; the
largest held one hundred sixty-five thousand cubic meters—“enough to cover
a football field to a depth of one hundred thirty feet.”19 A modern standard
LNG tanker of about one hundred twenty-five thousand cubic meters is about
a thousand feet long, one hundred fifty feet abeam, and cruises at twenty
knots. It is fueled partly by the gas (normally between an eighth and a quarter
of one percent per day) that constantly boils off as warmth seeps in
through the thermal insulation. LNG tankers carry unique safety equipment
and are subject to special rules, usually involving escorts and traffic restrictions,
when moving in harbor.
Once moored, a tanker discharges its LNG cargo in ten to fifteen hours.
The rate of LNG flow ranges up to one hundred ninety cubic meters per
minute—equivalent to about seventy-five thousand megawatts, or the rate at
which about seventy giant power stations send out energy. The pipes used in
this operation are exposed on the jetty, and lead to at least two tankers’ worth
of storage tanks, contained (with limitations noted below) by dikes. A typical
LNG storage tank, of which most terminals have several, is one hundred forty
feet high by one hundred ninety feet in diameter. It holds ninety-five thousand
cubic meters of LNG with a heat content equivalent to a quarter of an hour’s
total energy consumption for the entire United States, or to the energy
released by more than forty Hiroshima bombs.
LNG tankers have a fairly good safety record, but projections that it will continue
are unpersuasive.20 Even the limited reports available show some spills.21
One LNG carrier has gone aground, and three failed certification owing to
cracked insulation22—a loss of three hundred million dollars for Lloyds of
London. Double-hulled LNG tankers—unlike single-hulled, pressurized tankers
used for liquefied petroleum gas—are relatively resistant to damage by collision
or light attack. They could, however, be pierced by certain weapons available to
international terrorists, including limpet mines. Onboard sabotage would be rel92
Disasters Waiting to Happen
atively straightforward. Manipulation of onboard valves could in some circumstances
rupture the LNG tanks from overpressure.23 Alternatively, all LNG
tanker designs allow internal access below the tanks, and if a tank were deliberately
ruptured, ducts open at both ends and running the full length of the
cargo area would help to distribute liquid.24 Any such substantial spillage of
LNG onto the steel hull would probably shatter it. The General Accounting
Office warned that “Only an expert would recognize some types of explosive
material as explosives. One LNG ship crew member, trained in the use of explosives,
could cause simultaneous tank and hull damage...[which] might initiate an
extremely hazardous series of events.” (Ships carrying liquefied propane and
butane, described below, are even more easily sabotaged.)25
LNG terminals and storage tanks
The enormous amounts of LNG and, if it leaks, of flammable vapors make
LNG terminals and storage areas highly vulnerable. The world’s largest LNG
gasification plant, built at Arzew, Algeria at a cost of over four billion dollars,
narrowly escaped destruction one night a few years ago when a gas cloud
from a leaking tank drifted through it and dispersed without igniting. The
Tokyo Harbor terminal has luckily escaped damage in several marine fires
and explosions, including at least one major one from a liquid gas tanker. The
Canvey Island LNG terminal downriver from central London recently had its
third narrow escape from disaster when a two-hundred-thousand-ton oil
tanker collided with a Shell oil jetty that protrudes into the river upstream of
it at Coryton.26 On that occasion, the gush of oil was stopped before it caused
a major fire that could have spread downriver to the LNG plant. Years earlier,
this very nearly happened when the Italian freighter Monte Ulia sheared off
that same oil jetty, causing a melange of burning oil and trash barges to drift
downriver. A change of wind, fortuitous currents, and desperate firefighters
stopped the fire just short of the LNG terminal.27 One known and one suspected
incident of arson aboard a Texaco tanker have also recently endangered
the Canvey Island LNG terminal.28 At a similarly exposed position in
Boston Harbor lies the Everett Distrigas LNG terminal. It is near Logan
Airport, and its ship channel lies under the flight path for at least one runway.
In 1973, a Delta DC-9 on an instrument landing crashed into the seawall short
of that runway. Had a gas tanker been in the channel at the time, the errant
plane could have missed it by as little as a few feet.29
LNG terminals are vulnerable to natural disasters or sabotage. So are the
far more numerous peak-shaving LNG plants. (In 1978 the U.S. had forty-five
such plants, each storing more than twenty-three thousand cubic meters—three
Chapter Eight: Liquified Natural Gas 93
and a half times the total spill in the 1944 Cleveland disaster.) An audit of five
LNG and LPG sites by the General Accounting Office, the independent watchdog
agency of the U.S. government, found that at three of the sites, tanks had
very small earthquake safety margins; “two of these three sites, including three
large tanks, are located next to each other in Boston Harbor.”30
In Japan, LNG tanks are normally built underground, where they are better
protected from mishap and spills are more likely to be contained. In the
United States, LNG tanks are normally built aboveground and surrounded by
dikes. But General Accounting Office calculations and experiments suggest
that most dikes meant to contain minor leaks will in fact fail to contain at least
half of any sudden, major spill. Some thin dikes could fail altogether.31 Abrupt,
massive releases are indeed possible, as in Cleveland in 1944, because “if the
inner tank alone fails for any reason, it is almost certain that the outer tank
will rupture from the pressure and thermal shock.”32 It also appears that relatively
small cracks or holes in a large, fully loaded LNG tank could cause it
to fail catastrophically by instant propagation of the crack.33
This proneness to brittle fracture implies that relatively small disruptions
by sabotage, earthquake, objects flung at the tank by high winds, etc. could
well cause immediate, massive failure of an above-grade LNG tank. Certainly
enough weaponry is available to pierce such a tank with ease. The General
Accounting Office confirms that the equipment stolen from National Guard
armories includes
small arms, automatic weapons, recoilless rifles, anti-tank weapons, mortars, rocket
launchers, and demolition charges. A large number of commercially available
publications provide detailed instructions on the home manufacture of explosives,
incendiaries, bombs, shaped charges, and various other destructive devices. All the
required material can be bought at hardware stores, drug stores, and agricultural
supply outlets.... It is not unusual for international terrorist groups to be armed with
the latest military versions of fully automatic firearms, anti-aircraft or anti-tank
rockets, and sophisticated explosive devices.34
The General Accounting Office also found, however, that such sophistication
would not be necessary to cause a major LNG release. Live firing tests “confirmed
that the double-wall structure of [LNG]...tanks affords limited protection
even against non-military small arms projectiles, and that devices used by terrorists
could cause a catastrophic failure of the inner wall.”35 Some tanks allow
access to the insulation space through ground-level manholes, or are built in the
air on pilings, thus greatly increasing the effectiveness of explosive charges.
In 1978, none of the sixteen LNG facilities visited by the government auditors
had an alarm system. Many had poor communications and backup
94 Disasters Waiting to Happen
power sources. Guarding was minimal—often one unarmed watchman.
Procedures were so lax that “Access to all of the facilities we visited would be
easy, even for untrained personnel.”36
LNG shipments by truck
More than seventy-five insulated, double-walled trucks deliver LNG from
terminals to over one hundred satellite distribution tanks in thirty-one states,37
chiefly in urban areas.38 Some LNG may also be imported by truck from
Montreal to New England.39 More than ninety truckloads of LNG can leave
Boston’s Everett Distrigas terminal in a single day.40 Though puncture-resistant,
the trucks have points of weakness and a very high center of gravity,
encouraging rollover accidents.41 Each truck carries forty cubic meters of
LNG, with a heat content equivalent to a quarter of a kiloton of TNT, or
about a fiftieth of a Hiroshima yield.
Before LNG trucks are loaded, they are not inspected for bombs, nor are
the drivers required to identify themselves properly.42 Security is only marginally
better than for potato trucks.43 LNG trucks are easily sabotaged. The
double walls “are relatively thin,...and can be penetrated by a fairly small
improvised shaped charge. Properly placed, such a charge would cause LNG
to discharge into the insulation space, causing the outer jacket to fracture and
disintegrate.”44 Further, a truck could be hijacked from its fixed route for
extortion or for malicious use of its cargo. It is “particularly dangerous,
because [it allows]...the easy capture, delivery, and release of a large amount
of explosive material any place the terrorist chooses.”45
At least twelve LNG truck accidents had occurred in the United States by
1978. Two caused spills.46 One driver blacked out after driving far more than
the permitted number of hours and falsifying his logbook.47 Luckily, both
spills were in rural areas and neither ignited. Most LNG trucks leaving the
Everett facility travel on the elevated Southeast Expressway, a hazardous road
within a few blocks of the crowded Government Center area. In the first four
months of 1977 alone, there were four serious accidents on the Southeast
Expressway involving tractor-trailer trucks, one of which fell off onto the
streets below.48 An LNG truck would almost certainly break open in such an
accident.49 The entrances to the Sumner and Callahan Tunnels are about a
hundred yards downhill from the Southeast Expressway.50 The area is also
laced with basements, sewers, and subway tunnels into which the invisible,
odorless vapor would quickly spill.
“The forty cubic meters of LNG in one truck, vaporized and mixed with
air into flammable proportions, are enough to fill more than one hundred and
Chapter Eight: Liquified Natural Gas 95
ten miles of six-foot sewer line, or sixteen miles of a sixteen-foot-diameter subway
system.”51 That is enough, if the gas actually went that far and did not
leak out partway, to fill up virtually the entire Boston subway system. An
LNG spill into a sanitary sewer would vaporize with enough pressure to blow
back methane through domestic traps into basements.52 Even if buildings are
not involved, sewer explosions can damage large areas. Early on 13 February
1981, for example, an hour before rush-hour traffic, miles of streets in
Louisville, Kentucky were instantly torn up by an explosion of hexane vapor,
which had apparently leaked into the sewer system from a factory a mile from
the point of ignition.53 Such explosions can do great damage with only a few
cubic meters of flammable liquids,54 and have been used for sabotage.55
Analogous hazards of liquefied petroleum gas (LPG)
Liquefied petroleum gas (“LP Gas”)—the kind so commonly seen in metal
bottles in rural areas and trailer parks—consists almost entirely of either
propane or butane. These are by-products separated from natural gas at the
wellhead or, on occasion, derived from other parts of the petroleum system.
Unlike LNG, LPG is not regasified and piped to customers, but rather delivered
directly as a liquid. This is possible because propane and butane liquefy
at normal temperatures under modest pressure, or alternatively with moderate
cooling at atmospheric pressure.56 Because LPG is delivered to retail customers
as a liquid, it requires many small shipments. Yet because those shipments
make up about three percent of all U.S. energy supplies, vehicles carrying
LPG are ubiquitous. It is a far older and better-known fuel than LNG,
yet is less well studied and regulated—even though in some respects it may be
even more hazardous than LNG.
About eighty-five percent of the LPG in bulk storage is kept under pressure
in underground salt domes or caverns;57 the rest is stored aboveground
in tanks, often small ones. As these tanks are generally pressurized rather than
chilled, they do not require insulation as LNG tanks do. Instead, they have
only a single wall and hence are easily penetrated or destroyed. In 1978 the
U.S. had twenty aboveground LPG storage facilities with capacities greater
than twenty-three thousand cubic meters.
Most LPG is transported through some seventy thousand miles of highpressure
pipelines. The rest travels in sixteen thousand pressurized railcars (as
opposed to LNG, which does not move by rail) and in twenty-five thousand
pressurized tank trucks, whose squat cylindrical outlines are a daily sight on
our highways. A large LPG truck, like its LNG counterpart, holds about forty
cubic meters. But unlike an LNG truck, it is under pressure and is single96
Disasters Waiting to Happen
walled. It is therefore more vulnerable to breakage through accident or sabotage.
LPG trucks are also more likely to explode in fires, both because they
are uninsulated and because their cargo creates very high pressures by boiling
when exposed to heat.
Many LPG truck accidents have occurred worldwide58—often through faulty
repairs, delivery procedures, or valve operations.59 A truck laden with thirtyfour
cubic meters of LPG, for example, overturned in 1973 on a mountain road
above Lynchburg, Virginia, creating a fireball more than four hundred feet in
diameter.60 Four people were burned to death at the site, and three more at a distance
by the radiant heat. In a far more destructive accident near Eagle Pass,
Texas in 1975, a thirty-eight-cubic-meter LPG tank broke loose from its trailer.
Two explosions blew the front of the tank about sixteen hundred feet and the
rear (in three pieces) some eight hundred feet. Sixteen people were killed and
thirty-five injured.61 In Berlin, New York, in 1962, a twenty-eight-cubic-meter
LPG semi-trailer jack-knifed, hit a tree, and split. The tank was propelled eighty
feet back up the road, spewing gas as it went. After some minutes, the gas, having
spread over about five acres, ignited and burned in a few seconds, engulfing
ten buildings and causing ten deaths and seventeen injuries.62 And in West
St. Paul, Minnesota, a midnight LPG delivery fire in 1974 killed four people and
demolished large sections of three apartment buildings.63
LPG railcars, each containing about one hundred fifteen cubic meters
(equivalent to about an eighteenth of a Hiroshima yield),
are involved in many of the ten thousand railroad accidents that occur in this country
each year. There are often more than ten consecutive LPG cars on a train. Each
car can form a ten-second fireball about [four hundred feet]... in radius.64
This can cause third- and second-degree burns out to nearly three thousand feet
and to one mile respectively.65 The range can be even larger. In 1973, a slightly
oversized railcar of LPG developed a small leak while being unloaded. The ensuing
small fire burst the tank after nineteen minutes, causing a fireball nearly a
thousand feet in diameter. Thirteen people were killed. Many of the ninety-five
people injured were standing along a highway a thousand feet from the track.66
The General Accounting Office’s safety study of both LPG and LNG
notes a further danger of LPG tankers and railcars:
If vapors from one LPG car ignite, the fire may rupture an unpunctured car in a
“Boiling Liquid Expanding Vapor Explosion,” or BLEVE [where sudden depressurization
rapidly boils and expels the LPG as an aerosol-vapor-air mixture]. Each
fire and explosion contributes to the heating and weakening of neighboring cars
and makes additional explosions more likely. A BLEVE can rocket a forty-fivethousand-
pound steel section of a tank for a quarter of a mile. This is what hapChapter
Eight: Liquified Natural Gas 97
pened in a derailment near Oneonta, New York, in 1974. LPG vapor from a
crushed LPG car quickly ignited and formed a fireball. Fire fighters attempting to
cool down several other LPG cars were caught in a subsequent explosion; fiftyfour
were injured.... In a 1974 railyard accident near Decatur, Illinois, an LPG railcar
was punctured; the resulting cloud did not ignite immediately, but spread and
then exploded over an area one-half by three-quarters of a mile. [The blast was felt
forty-five miles away;67 such unconfined vapor-air explosions are similar to those
caused by military fuel-air bombs, some of which use propane.] There were seven
deaths, three hundred forty-nine injuries, and twenty-four million dollars in damage
[including blast damage out to two and a half miles]. Litter and debris...covered
twenty blocks of the city.... LPG railcars travel through densely populated
areas of cities, even cities which prohibited LPG storage.68
LPG trains could easily be derailed at any desired point: “youth gangs frequently
place obstacles on tracks which delay freight trains in New York City
just to harass the trainmen,”69 and similarly in Los Angeles.70 Sabotage causing
serious damage to trains has occurred across the U.S.,71 including trains
carrying LPG (which fortunately did not leak)72 and chlorine (whose leakage
in a Florida derailment killed eight people and injured nearly a hundred).73
LPG railcars are only a tenth as numerous as tankers carrying other hazardous
cargoes, and are thus likely to occur in the same trains with chlorine,
oil, industrial chemicals, and so forth. Such cargoes and LPG can endanger
each other. Railcars spend a good deal of time sitting in switchyards where
they are subject to tampering and fires. Ammunition trains have blown up in
switchyards. A few years ago, a chemical tank car being shunted in
Washington State exploded with the force of several World War II blockbusters.
A forty-hour fire in a railcar of toxic ethylene oxide recently shut the
Port of Newark and curtailed flights at Newark International Airport for fear
of an explosion that could hurl shrapnel for a mile.74 Far less would be enough
to breach an LPG railcar. Its steel wall is only five-eighths of an inch thick,
and “can be easily cut with pocket size explosive devices [or by] many other
weapons commonly used by terrorists....”75 A small leak can be dangerous
because LPG vapor is heavier than air even when it warms up (unlike LNG
vapor, which is heavier than air only so long as it remains chilled). LPG vapor
can therefore flow for long distances along the ground or in sewers or tunnels.
When a mixture of between about two and nine percent LPG vapor in air
reaches a small spark, it will ignite or explode.
LPG terminals, as well as shipments by road and rail, penetrate the most
vulnerable parts of our industrial system. The General Accounting Office has
published an aerial photograph of a major LPG receiving terminal near Los
Angeles Harbor.76 Its propane storage tanks, a stone’s throw from the Palos
Verdes earthquake fault, are surrounded on one side by a large U.S. Navy fuel
98 Disasters Waiting to Happen
depot and by a tank farm, and on the other side by a dense residential area
that runs for miles. All are within the range of an LPG conflagration. Marine
LPG tankers add to the hazard and can endanger the terminal itself. In 1974,
the LPG tanker Yuyo Maru collided and burned in Tokyo Bay with the loss of
thirty-three crew. In 1968, the small Swedish LPG tanker Claude, having collided
with a freighter in Southampton water, was abandoned by her crew and
shortly thereafter by her pilot (who supposed the crew must know what was
good for them). Claude drifted under reverse power, went aground, was towed
to a refinery, and started to have a chartered vessel pump off her cargo. But
when one hose sprang a leak, Claude was again precipitately abandoned by
that vessel, rupturing all the hoses and pipelines.77 It was only luck and the
courage of a few remaining crewmen that got the valves shut before the gas
cloud ignited, for it could well have destroyed the refinery too.
In 1977, a fifty-thousand-cubic-meter refrigerated propane tank in Qatar,
designed by Shell International on a pattern similar to that of tanks in the Los
Angeles terminal, suddenly collapsed, sending liquid propane over the dike.
The resulting explosion destroyed the LPG facility surrounding the tank. In
France, eleven people died and seventy were injured when vapor from a leaking
butane tank was ignited by a truck passing more than five hundred feet
away, leading to the explosion of eight butane and propane tanks.78 In a littlenoted
incident on 30 January 1981, an FB-111 aircraft crashed a quarter-mile
from the edge of the tank farm in the second largest LPG/LNG facility in New
England (in Newington, New Hampshire). The plant is about two miles from
the center of Portsmouth (population about twenty-seven thousand), two and
a half miles from a nuclear submarine base, and three-quarters of a mile from
Pease Air Force Base with its huge fuel depot. For comparison, the direct fireball
radiation alone from the burning of thousands of cubic meters of LPG can
start fires and cause third-degree burns at ranges of a mile or more.79
The risk from liquefied energy gases (LEG)
In practical effect, the most densely industrialized and populated areas in
America have potential bombs in their midst, capable of causing disastrous
explosions and firestorms without warning. As the General Accounting Office
summarized, describing both LNG and LPG by the generic term “liquefied
energy gases” (LEG):
Successful sabotage of an LEG facility in an urban area could cause a catastrophe.
We found that security precautions and physical barriers at LEG facilities are generally
not adequate to deter even an untrained saboteur. None of the LEG storage
Chapter Eight: Liquified Natural Gas 99
areas we examined are impervious to sabotage, and most are highly vulnerable.80
In many facilities, by manipulating the equipment, it is possible to spill a large
amount of [LEG]... outside the diked area through the draw-off lines. LEG storage
facilities in cities are often adjacent to sites that store very large quantities of other
hazardous substances, including other volatile liquids. Thus, a single cause might
simultaneously destroy many tanks, or a spill at one facility might cause further
failures at adjacent facilities.81
These might include ports, refineries, tank farms, or power stations. For example,
although the Cove Point, Maryland LNG terminal is not near a city, it is
five miles upwind—well within plume range—of the Calvert Cliffs nuclear
power plant, which probably could not withstand being enveloped in a fireball.
The General Accounting Office report concluded:
Nuclear power plants are built to higher standards than any other type of energy
installation, much higher than those for LEG installations. Nevertheless, they are
never located in densely populated areas. We believe that new large LEG facilities
also should not be located in densely populated areas.82
LNG shipments and facilities likewise perforate America’s industrial heartland.
Even the most sensitive “chokepoints” are put at risk. In February 1977,
for example, LNG was being trucked along the Staten Island Expressway and
across the Verrazano Narrows and Goethals Bridges.83 Seven Mile Bridge, the
only land access to the lower Florida Keys, was heavily damaged by a recent
propane-truck explosion,84 which could as well have occurred on any urban
bridge in America. It is apparently common for LNG shipments to pass near
major oil, gas, and nuclear facilities, few if any of which could withstand
envelopment in a burning gas cloud. While many local authorities would like
to restrict such shipments before a catastrophe, the regulation of such interstate
commerce is federally pre-empted; and so far, despite the devastating
criticisms by the General Accounting Office, the dozen or so responsible federal
agencies have done little of substance to improve safety.
Perhaps additional LNG imports, brought by eighty-plus large tankers into
a half-dozen U.S. terminals, will never happen as enthusiasts once hoped, if
only for the economic reasons alluded to earlier. But unless tackled directly,
the clear and present dangers from present LNG and—on a far greater scale—
LPG operations will persist. Later chapters will show that all the energy now
supplied by LNG and LPG can be replaced by much cheaper sources which
do not compromise national security.

No hay comentarios:

Publicar un comentario