On 18 March 1967, owing to a navigational error, the
Torrey Canyon struck Pollard's Rock in the Seven Stones reef between the Cornish mainland and the Scilly Isles.
This was the first major oil spill; a fairly adequate outline of how
to deal with a coastal oil spill had been issued to local authorities
some years previously but had apparently been forgotten, so it was
widely reported that no plans had been prepared beforehand to deal with
it. The tanker had to be ready to deliver its cargo to anywhere in the
world, and so only had small-scale charts; she used LORAN but not the
more accurate Decca Navigator.
When the risk of collision with a fishing fleet became obvious, there
was some confusion between the Master and the helmsman (who was
actually the cook and had little experience) as to whether she was in
manual or automatic steering mode; by the time this was resolved, it
was too late.
Unsuccessful attempts were made to float the ship off the
reef, and one member of the Dutch salvage team was killed. The ship
broke apart after being stranded on the reef for several days and
bombed by aircraft.
Attempts to use foam booms to contain the oil were also of limited success due to their fragility in high seas.
Some 50miles (80km) of French and 120miles (190km) of Cornish coast were contaminated. Around 15,000 sea birds
were killed, along with huge numbers of marine organisms, before the
270 square miles (700km²) slick dispersed. Much damage was caused by
the heavy use of so-called detergents
to break up the slick - these were first-generation variants of
products originally formulated to clean surfaces in ships'
engine-rooms, with no concern over the toxicity of their components,
and many observers believed that they were officially referred to as
'detergents', rather than the more accurate 'solvent-emulsifiers', to
encourage comparison with much more benign domestic cleaning products.
Some 42 vessels sprayed over 10,000 tons of these dispersants onto the
floating oil and they were also deployed against oil stranded on
beaches.
In Cornwall, they were often misused - for example, by
emptying entire 45-gallon drums over the clifftop to 'treat'
inaccessible coves or by pouring a steady stream from a low-hovering
helicopter. On the heavily-oiled beach at Sennen Cove,
dispersant pouring from drums was 'ploughed' into the sand by
bulldozers over a period of several days, burying the oil so
effectively that it could still be found a year or more later. It is
probable that the general resistance to the proper use of
later-generation, much-improved oil-spill dispersants arose as a result
of this operation.
Claims were made by the British and
French Governments against the
owners of the vessel and the subsequent settlement was the largest ever
in marine history for an oil claim.
The British Government was only
able to serve its writ against the owners by arresting the Torrey
Canyon's sistership, the Lake Palourde, when she put in for minor
provisions at Singapore, four months after the oil spill.
A young
British lawyer, Anthony O'Connor, from a Singaporean law firm, Drew
& Napier,
was deputised to arrest the ship on behalf of the British Government by
attaching a writ to its mast. O'Connor was able to board the ship and
serve the writ as the ship's crew thought he was a whisky salesman. The
French Government, alerted to the Lake Palourde's presence, pursued the
ship with motor boats, but were unable to board and serve their writ.
The disaster led to many changes in
international regulations, for example the Civil Liability Convention
(CLC) of 1969, which imposed strict liability on ship owners without
the need to prove negligence, and the 1973 International Convention for
the Prevention of Pollution from Ships.
The
Sea Star
was a South Korean supertanker that spilled some 115,000 tons of crude
oil into the Gulf of Oman on December 19, 1972, after colliding with
the Brazilian tanker
Horta Barbosa.
After the collision both vessles caught fire and were abandoned by their crews. Recovery of the the
Sea Star
was attempted before the fires on board were extenguished, but
following several explosions the vessle sank into the Gulf on December
24.
Metula grounded in the eastern Strait of Magellan,
Chile, on 9 August 1974. About 47,000 tonnes of light Arabian crude oil
and 3,000 to 4,000 tonnes of heavy fuel oil are estimated to be have
been lost.
Large volumes of water-in-oil emulsion were produced in the
rough sea conditions and much of this landed on shores of northern
Tierra del Fuego. Most of the shores affected were of mixed sand and
gravel, but two small estuaries including saltmarshes were also oiled.
About 4,000 birds are known to have been killed, including cormorants
and penguins.
No cleanup was done because of
the remoteness of the area and consequently this remains a distinctive
spill site mainly because hard asphalt pavements formed on many
shorelines. The long-term fate and effects of heavy oiling have been
extensively investigated.
One very sheltered marsh received thick
deposits of mousse and, 20 years after the spill, these deposits were
still visible on the marsh surface, with the mousse quite fresh in
appearance beneath a weathered surface skin. Little plant
re-colonisation has occurred in the areas with thicker deposits of 4 or
more cm, though it is proceeding in more lightly oiled areas.
On sand
and gravel shores, an asphalt pavement remained in a relatively
sheltered area in 1998, but oil deposits had mainly broken up and
disappeared from more exposed shores. These remain amongst the
longest-term contaminants recorded for an oil spill, even though they
have not resulted in significant impacts on fisheries or the biology of
coastal waters.
| 1976. - The Argo Merchant |
Argo Merchant ran aground on Nantucket Shoals, off
Massachusetts, USA, on 15 December 1976, and over the next month
spilled her entire cargo (28,000 tonnes) of Venezuelan No 6 fuel oil
and cutter stock.
Storms broke up the tanker after grounding, and
attempts to pump the oil into another vessel failed. In-situ burning
was attempted on two occasions, but the slick failed to remain alight.
Winds
during the spill period were offshore from Massachusetts, and as a
result no oil from
Argo Merchant ever reached the shoreline and no
coastal impact was reported.
Hydrocarbon contamination of the bottom
sediments was restricted to an area immediately around the wreck, and
apparently was short-lived. The bulk of the spill formed large
'pancakes' and sheens on the surface; these were carried offshore over
the continental shelf and into the prevailing North Atlantic
circulation pattern. The cutter stock, which was mixed with the fuel
oil to improve handling, entered the water column.
Despite its
relatively high potential toxicity, there was little evidence of impact
on the marine fauna or phytoplankton.
The accident occurred at the time
when the fewest potential effects on pelagic organisms would be
expected; a period of low productivity in the water column, with few
fish eggs and larvae present. Oiled birds were seen near the wreck, and
though total mortalities are difficult to evaluate, it was concluded
that the spill probably had little effect on the coastal and marine
bird populations off the New England coast.
The outcome of the
Argo Merchant oil spill appears to have been fortunate in several respects:
- the winds were almost continuously offshore, preventing the oil from
coming on the beaches; the density of the oil was low enough so that it
did not sink and contaminate the bottom, and the spill occurred in the
winter when the biological activity, productivity, and fishing
activities are relatively low.
The tanker Amoco Cadiz ran aground off the coast of
Brittany on 16 March 1978 following a steering gear failure.
Over a
period of two weeks the entire cargo of 223,000 tonnes of light Iranian
and Arabian crude oil and 4,000 tonnes of bunker fuel was released into
heavy seas. Much of the oil quickly formed a viscous water-in-oil
emulsion, increasing the volume of pollutant by up to five times. By
the end of April oil and emulsion had contaminated 320km of the
Brittany coastline, and had extended as far east as the Channel Islands.
Strong
winds and heavy seas prevented an effective offshore recovery
operation. All told, less than 3,000 tonnes of dispersants were used.
Some chalk was also used as a sinking agent, but with the consequence
of transferring part of the problem to the sea bed.
The at-sea response
did little to reduce shoreline oiling. A wide variety of shore types
were affected, including sandy beaches, cobble and shingle shores,
rocks, seawalls and jetties, mudflats and saltmarshes. Removal of bulk
free oil trapped against the shore using skimmers proved difficult,
largely due to problems with seaweed and debris mixed with the oil.
Greater success was achieved with vacuum trucks and agricultural vacuum
units, although much of the free oil was simply removed by hand by more
than 7,000 personnel (mainly military). A considerable portion of the
oil that did come ashore eventually became buried in sediments and
entrapped in the low energy salt marshes and estuaries.
At
the time, the Amoco Cadiz incident resulted in the largest loss of
marine life ever recorded after an oil spill.
Two weeks after the
accident, millions of dead molluscs, sea urchins and other benthic
species washed ashore. Although echinoderm and small crustacean
populations almost completely disappeared from some areas, populations
of many species had recovered within a year. Diving birds constituted
the majority of the nearly 20,000 dead birds that were recovered.
Oyster cultivation in the estuaries ("Abers") was seriously affected
and an estimated 9,000 tonnes were destroyed because of contamination
and to safeguard market confidence. Other shell and fin fisheries as
well as seaweed gathering were seriously affected in the short-term, as
was tourism.
Cleanup activities on rocky shores, such as
pressure-washing, as well as trampling and sediment removal on salt
marshes caused biological impacts. Whilst rocky shores recovered
relatively quickly, the salt marshes took many years.
Failure to remove
oil from temporary oil collection pits on some soft sediment shorelines
before inundation by the incoming tide also resulted in longer-term
contamination. Numerous cleanup and impact lessons were learned from
the Amoco Cadiz incident, and it still remains one of the most
comprehensively studied oil spills in history.
On June 3, 1979, the 2 mile deep exploratory well, Ixtoc I, blew out in
the Bahia de Campeche, 600 miles south of Texas in the Gulf of Mexico.
The Ixtoc I was being drilled by the SEDCO 135, a semi-submersible
platform on lease to Petroleos Mexicanos (PEMEX). A loss of drilling
mud circulation caused the blowout to occur.
The oil and gas blowing
out of the well ignited, causing the platform to catch fire. The
burning platform collapsed into the wellhead area hindering any
immediate attempts to control the blowout.
PEMEX hired blowout control experts and other spill control experts
including Red Adair, Martech International of Houston, and the Mexican
diving company, Daivaz. The Martech response included 50 personnel on
site, the remotely operated vehicle TREC, and the submersible Pioneer
I.
The TREC attempted to find a safe approach to the Blowout Preventer. The approach was complicated by poor visibility and debris on
the seafloor including derrick wreckage and 3000 meters of drilling
pipe. Divers were eventually able to reach and activate the BOP, but
the pressure of the oil and gas caused the valves to begin rupturing.
The BOP was reopened to prevent destroying it.
Two relief wells were
drilled to relieve pressure from the well to allow response personnel
to cap it. Norwegian experts were contracted to bring in skimming
equipment and containment booms, and to begin cleanup of the spilled
oil. The Ixtoc I well continued to spill oil at a rate of 10,000 -
30,000 barrels per day until it was finally capped on March 23, 1980.
| 1979. - Atlantic Empress and the Aegean Captain |
On
19 July 1979 at 7pm, two loaded VLCCs (Very Large Crude Carriers),
the Atlantic Empress (carrying 276,000 tonnes of crude oil) and
the Aegean Captain (carrying 200,000 tonnes of crude oil) collided
with each other in the Caribbean Sea, off Tobago island. The Atlantic
Empress and the bow part of the Aegean Captain went up in flames.
26 sailors were killed.
The crew of the Aegean Captain managed to control the fire in the
ship. She was towed the following days towards Trinidad and then
Curacao, losing small quantities of oil on the way, which a tug
boat sprayed with dispersants. In Curacao, the cargo was transferred
into other vessels.
The burning Atlantic Empress was towed towards the open sea, surrounded
by vessels hosing the fire and followed by an oil slick which was
partly in flames. A major fire-fighting operation was carried out,
as well as the treatment of the pollution with dispersants.
However,
despite the response team's efforts, a series of explosions shook
the ship on 23 and 24 July. The 29 July saw a more powerful explosion
and the fire increased. On 2nd August, the shipwreck began to list,
the oil spilled at an increasing rate and the towrope was released.
The remaining parts of the Atlantic Empress continued to burn furiously
in the middle of a burning oil slick and disappeared under a huge
cloud of black smoke. On 3 August at dawn, only an oil slick remained
on the surface of water. The biggest vessel ever to have sunk had
disappeared after 15 days of agony. Followed by surveillance tug
boats, the oil still visible at the surface had totally disappeared
by 9 August, without touching the shore.
The
total loss of the 280,000 tonnes of oil as a result of this collision
holds the world record for an oil tanker accident. Nobody will ever
know what was burned and what was dispersed by the sea. No significant
shore pollution was recorded on the nearest islands. No impact study
was carried out, either by the surrounding countries, or the international
community, as awareness regarding marine pollution was less developed
then than it is today. Furthermore, at that time all eyes were turned
towards another disaster, the explosion of the Ixtoc I drilling
rig in the Gulf of Mexico.
On the morning of November 1, 1979, the Burmah Agate and the Mimosa
collided at the entrance to Galveston Harbor. The Mimosa struck the
Burmah Agate on its starboard side, tearing an 8 by 15 foot hole in the
hull near Cargo Tank No. 5.
An explosion occurred upon impact, and the
leaking oil ignited.
The USCG immediately dispatched the Coast Guard
Cutter Valiant to begin search and rescue operations. By 1230 all 26
crew members of the Mimosa had been found, but only 6 of the Burmah
Agate's 37 crew members were accounted for.
The owners of the Burmah
Agate assumed responsibility for the spill response. They contracted
Clean Water, Inc. for cleanup operations, and Smit International Inc.
to fight fires on the Burmah Agate, and to assist in salvage. The
Burmah Agate burned until January 8, 1980 and was towed to Brownsville,
Texas on February 1 for scrapping. USCG district 8.
| 1983. - Castillo de Bellver |
Castillo De Bellver, carrying 252,000 tonnes of
light crude oil (Murban and Upper Zakum), caught fire about 70 miles
north west of Cape Town, South Africa on 6 August 1983. The blazing
ship drifted off shore and broke in two.
The stern section - possibly
with as much as 100,000 tonnes of oil remaining in its tanks - capsized
and sank in deep water, 24 miles off the coast. The bow section was
towed away from the coast and was eventually sunk with the use of
controlled explosive charges. Approximately 50-60,000 tonnes are
estimated to have spilled into the sea or burned. Although the oil
initially drifted towards the coast, a wind shift subsequently took it
offshore, where it entered the north-west flowing Benguela Current.
Although
a considerable amount of oil entered the sea as a result of the Castillo De Bellver incident, there was little requirement for cleanup
(there was some dispersant spraying) and environmental effects were
minimal.
The only visible damage was the oiling of some 1,500 gannets,
most of which were collected from an island near the coast where they
were gathering for the onset of the breeding season. A number of seals
were observed surfacing in the vicinity of the dispersant spraying
activities but were not thought to have suffered any adverse effects.
Also
of initial concern was the 'black rain' of airborne oil droplets that
fell during the first 24 hours of the incident on wheat growing and
sheep grazing lands due east of the accident, although no long-term
damage was recorded from these residues. The impact on both the rich
fishing grounds and the fish stocks of the area was also considered to
be negligible.
Exxon Valdez grounded on Bligh Reef in Prince
William Sound, Alaska, on 24 March 1989. About 37,000 tonnes of Alaska
North Slope crude escaped into the Sound and spread widely. There was
some limited dispersant spraying and an experimental in-situ burn trial
during the early stages of the spill, but at-sea response concentrated
on containment and recovery.
Despite the utilisation of a massive
number of vessels, booms and skimmers, less than 10% of the original
spill volume was recovered from the sea surface. The oil subsequently
affected a variety of shores, mainly rock and cobble, to varying
degrees over an estimated 1,800km in Prince William Sound and along
Alaska's south coast as far west as Kodiak Island.
This
spill attracted an enormous amount of media attention because it was
the largest spill to date in US waters (although well down the scale in
world terms). Moreover, it happened in a splendidly scenic wilderness
area with important fisheries and attractive wildlife such as sea
otters and bald eagles.
Consequently the response was the most
expensive in oil spill history, with over 10,000 workers being employed
at the height of the cleanup operations, many o them in shoreline
cleanup, often in remote areas. The clean-up cost for the first year
alone was over US$2 billion.
Shoreline cleanup
techniques included high pressure, hot water washing, which was carried
out on a scale never attempted previously or subsequently. This caused
substantial impact in intertidal communities and may have delayed their
recovery in some areas, although recovery on over 70% of oiled
shorelines was progressing well one year after the spill.
There were
also some relatively large scale bioremediation trials that gave mixed
results. About 1,000 sea otters are known to have died, and over 35,000
dead birds were retrieved. There were particular efforts to protect
fisheries, for example with booming of salmon hatcheries.
Oil residues
remain trapped in intertidal sediments at a few locations and
scientists dispute the evidence of long-term damage to wildlife and
fish populations. Indeed, assessment of damage and recovery has been
controversial because of the segregation of scientists into different
camps, as a result of US litigation practices.
On
19 December 1989, the Iranian oil tanker Khark 5, en route from
Kharg Island to Rotterdam, was caught in a storm and suffered
an explosion off the coast of Safi, 400 miles north of the Canary
Islands. Four tanks were damaged causing a continuous spill of
70,000 tonnes of Iranian crude oil, a quarter of the vessel's
cargo. Over about 12 days, leaks estimated at 200 t/h were reported.
The
explosion was followed by a fire which was quickly controlled.
The vessel was then towed by a Smit Tak tug to move it away from
the Moroccan coast. For several weeks, a port of refuge or sheltered
area was sought in order to carry out a lightering operation.
However, no country gave the vessel permission to approch its
coast and so the oil continued to flow at sea. As with the Tanio,
this incident once again highlighted the issue of ports and zones
of refuge.
The
Moroccan government was poorly prepared to face an accidental
oil spill and was given assistance by international experts.
In
total, the cargo carried by Khark 5 consisted of 225,000 tonnes
of Iranian crude oil. Aromatic petroleum products made up a third
of this cargo. This high proportion of aromatics favoured the
evaporation of the oil into the atmosphere and its dispersion
in the water mass in the form of micelles, thus avoiding heavy
ecological impact.
Oil
slick dispersal, cleaning and recovery operations required the
mobilization of considerable human and material resources. Daily
flights over the slick were carried out to observe its movement
toward the Moroccan and Spanish coasts (the Canary Islands).
Treatment
of the slicks was carried out using dispersants but was soon stopped
as it proved ineffective due to the oil not forming a sufficiently
dense and continuous slick. No arrivals of oil on the Moroccan
coast were reported, nor were any beachings of dead animals.
On February 7, 1990 at 1620, the single-hull tank vessel American
Trader grounded on one of its anchors while approaching the Golden West
Refining Company's offshore mooring.
Two holes were punctured in one of
the vessel's cargo tanks, releasing 9458 barrels of heavy crude oil
into the water approximately 1.3 miles from Huntington Beach,
California. The master of the vessel immediately reported the incident
to the USCG Marine Safety Office/Group Los Angeles-Long Beach.
The master moved the American Trader into deeper
water one mile to the south. The commanding officer of the MSO/Group
assumed the role of the Federal On-Scene Coordinator (FOSC). The
responsible parties assumed full financial responsibility for the spill
and sent representatives to the Long Beach area.
Oil began to come
ashore on February 8 in light concentrations around Newport Pier. By
February 9, oil was ashore at Huntington Beach; in some instances, oil
in the surf zone here appeared to be in heavier concentrations than
observed earlier at Newport Beach.
Calm seas and fair weather for most
of the response period resulted in a rapid and successful cleanup. All
of the beaches were cleaned by March 2. The FOSC concluded all cleanup
operations by April 3.
The 22,000 barrels of crude remaining in the
damaged cargo tank were lightered by personnel from the USCG Pacific
Strike Team and the responsible party using the USCG Air-Deliverable
Anti-Pollution Transfer System (ADAPTS). By 1200 on February 9, the oil
from the damaged tank plus 90,000 barrels from the mid-body tanks had
been transferred into barges to decrease the draft of the vessel.
Temporary patches were applied to the holes in the hull and the
American Trader was moved to an oil transfer facility in Long Beach
Harbor to off-load the remaining 470,000 barrels of crude oil. The
vessel was moved to San Francisco on February 18 for drydocking and
repair.
On June 8, 1990 at approximately 2330, while the Italian tank vessel
Fraqmura was lightering the Norwegian tank vessel Mega Borg, an
explosion occurred in the pump room of the Mega Borg.
The two ships
were in the Gulf of Mexico, 57 miles southeast of Galveston Texas in
international waters, but within the U.S. exclusive economic zone. As a
result of the explosion, a fire started in the pump room and spread to
the engine room.
An estimated 100,000 barrels of Angolan Palanca crude
was burned or released into the water from the Mega Borg during the
next seven days.
Approximately 238 barrels of oil was discharged when
the Fraqmura intentionally broke away from the Mega Borg. Explosions on
the Mega Borg, caused the stern of the ship began to settle lower in
the water and list to the port side. A continuous discharge of burning
oil flowed over the aft port quarter of the ship.
Less than an hour after the explosions on the Mega Borg, the U.S. Coast
Guard (USCG) in Galveston dispatched two USCG cutters to the scene.
Weather was calm throughout the incident. Winds were generally around
10 to 15 knots and air temperature were between 80 and 90 degrees
Fahrenheit.
On 3 December 1992, the 114,000 tonne Greek-flagged OBO carrier Aegean Sea,
carrying 80,000 tonnes of crude oil,
grounded in bad weather while entering La Coruna, Spain.
The pilot was just about to board the ship when she grounded.
The impact fractured the hull spilling about 74,000 tonnes
which subsequently caught fire and the ship exploded.
Being an OBO ship Aegean Sea had a double hull.
The cause of the accident was again human error
caused by faulty navigation in bad weather conditions.
Following engine failure, Braer ran aground in
severe weather conditions on Garth's Ness, Shetland on 5 January 1993.
Over a period of 12 days the entire cargo of 84,700 tonnes of Norwegian
Gullfaks crude oil, plus up to 1,500 tonnes of heavy bunker oil, were
lost as almost constant storm force winds and heavy seas broke the ship
apart.
Weather conditions prevented the use of mechanical recovery
equipment at sea, although about 130 tonnes of chemical dispersant was
applied from aircraft during periods when the wind abated slightly and
some oil remained on the surface. Oiling of shorelines was minimal
relative to the size of the spill and cleanup involved the collection
of oily debris and seaweed by a small workforce.
The
Braer spill was very unusual in that a surface slick was not produced.
A combination of the light nature of the oil and the exceptionally
strong wind and wave energy naturally dispersed the oil throughout the
water column.
The oil droplets were adsorbed onto sediment particles
which eventually sank to the sea bed. Sub-surface currents led to this
oil being spread over a very wide area, although a significant portion
eventually ended up in two deep, fine sediment 'sinks'.
A
wide range of fish and shellfish over a fairly large area became
contaminated with oil, resulting in the imposition of a Fisheries
Exclusion Zone. Farmed salmon held in sea cages in the surface waters
within this zone bore the brunt of the contamination since they could
not escape the cloud of dispersed oil.
Although this contamination was
lost quickly once clean water conditions returned, millions of salmon
that could not be marketed had to be destroyed. The Exclusion Zone was
progressively lifted as fish and shellfish species were found by
chemical analysis and taste testing to be free of contamination,
although it was still in place over 6 years after the spill for mussels
and Norway lobsters at some sites within the closure area.
The
Braer spill was unusual in that a significant amount of oil was blown
on to land adjacent to the wreck site. The effects of this airborne oil
were localised and had no more than a temporary impact on vegetation
and livestock. Seabird casualties were also relatively low. Considering
the size of the spill, the environmental impacts were surprisingly
limited.
1993. - Barge Bouchard 155
|
On August 10, 1993, at approximately 0545, the freighter Balsa 37, the
barge Ocean 255, and the barge Bouchard 155 collided in the shipping
channel west of the Skyway Sunshine Bridge south of Mullet Key in Tampa
Bay, FL. MSO Tampa closed the port to vessel traffic.
This collision
caused three separate emergencies: 1) the Balsa 37, which was carrying
a cargo of phosphate rock, was severely damaged on the starboard side,
was listing at an increasing rate, and was in danger of capsizing in
the channel; 2) the Ocean 255, which was loaded with jet fuel,
gasoline, and a small amount of diesel fuel was burning out of control
just south of Mullet Key; and 3) the Bouchard 155 was holed at the port
bow spilling approximately 8,000 barrels of #6 fuel oil into Tampa Bay.
Stabilizing the vessels was the first priority of responders. By 2200
the Ocean 255 barge fire was extinguished and the GST was conducting
cooling procedures and maintaining a fire watch. Lightering operations
were well underway on the Bouchard 155 barge in preparation for moving
it to dockage in the Port of Tampa where it would be cleaned before dry
docking.
The Balsa 37 was intentionally grounded outside the shipping
channel to prevent it from capsizing and to open the channel for
traffic while repairs and stability evaluations were conducted.
August 10 overflight observations showed a three- to six-meter wide
band of oil along the beaches.
By the next day, this band appeared to
be about half its original width. Systematic shoreline surveys were
conducted and oil was found buried by two to eight inches of clean sand
deposited during high tide. Cleanup crews focused on manually removing
the band of surface oil high on the beach.
A plan was developed to
remove the subsurface oil without generating large volumes of sediment
for handling, disposal, and replacement. The plan called for mechanical
removal of the heavy buried layers, manual removal of moderately oiled
sediments, and mechanically pushing stained sand onto the lower part of
the beach for surf washing.
Pompoms were strung along the surf zone to
collect any oil refloated during the surf washing.
By August 11 the status of the vessels had improved substantially. The
response focus began to change from emergency issues to skimming
operations, protection strategies, forecasts, and planning.
Meanwhile, cleanup crews were contending with very thick oil that had
been deposited around some mangrove islands.
Tarmats formed when
sediment was mixed with oil along the shallow flats surrounding the
islands. Large thick mats coated mangrove roots, oyster and seagrass
beds, and tidal mud flats. Most of this oil was vacuumed out using
vacuum transfer units on grounded barges staged around the islands and
shallow areas.
Seawalls within the bay were being washed using
high-pressure water heated to 110 degrees.
The GST was onscene throughout the spill response. They provided
support with the Vessel of Opportunity Skimming System as well as the
fire fighting, monitoring, and lightering of the Ocean 255 barge.
Roughly 14.5 miles of fine-grained sand beach from St. Petersburg Beach
north to Redington Shores Beach were affected by this spill. Sand
beaches on Egmont Key at the entrance to Tampa Bay were also oiled.
Additionally, four mangrove islands inside the entrance to Boca Ciega
Bay at Johns Pass and two small areas of Spartina marsh were oiled.
Jetties, seawalls, and riprap within the bay and at Johns Pass and
Blind Pass were also oiled to varying degrees. It is estimated that
over 30 miles of residential seawalls were oiled within Boca Ciega Bay.
Some impact also occurred on the northern side of Mullet Key at Bonne
Fortune Key in fringing mangroves.
On the evening of 15 February 1996, Sea Empress,
carrying 130,000 tonnes of Forties Blend North Sea crude oil, ran
aground in the entrance to Milford Haven, South West Wales.
Although
the tanker was refloated within a couple of hours, it sustained serious
damage to its starboard and centre tanks, resulting in a massive
release of oil. Attempts to bring the vessel under control and to
undertake a ship-to-ship transfer operation were thwarted by severe
weather and the tanker grounded and refloated several more times over a
period of five days.
In all, some 72,000 tonnes of crude oil and 370
tonnes of heavy fuel oil were released into the sea between the initial
grounding and the final refloating operation.
The Sea Empress cleanup operations were wide-ranging and effective. At sea
these included dispersant spraying, mechanical recovery and the use of
the protective booms. This, coupled with a high rate of evaporation and
natural dispersion, greatly reduced the quantity of oil reaching
inshore waters.
Some 200km of coastline - much of it in a National Park
- was contaminated and a major shoreline cleanup effort had to be
mounted, involving mechanical recovery, trenching, beach washing, and
the use of dispersants and sorbents. The main recreational beaches were
cleaned by the Easter holidays, some two months after the spill,
although other areas required longer treatment throughout the summer.
A
temporary ban was imposed on commercial and recreational fishing in the
region and there was concern that tourism, important to the local
economy, would be badly affected by the heavily oiled beaches. Several
thousand oiled birds washed ashore, leading to a major cleaning and
rehabilitation operation.
The UK government
appointed an independent committee, the Sea Empress Environmental
Evaluation Committee (SEEEC), to assess the damage caused by the spill.
It found that although some wildlife populations were damaged (some
severely) and a few would take years to recover, the great majority
proved resilient and after two years had regained their former
abundance.
It appears that although a very large amount of oil was
spilled in a particularly sensitive area, the impact was far less
severe than many people had expected. This was due to a combination of
factors - in particular, the time of year, the type of oil, weather
conditions at the time of the spill, the cleanup response and the
natural resilience and recovery potential of many marine species.
The Maltese tanker Erika, carrying some 31,000
tonnes of heavy fuel oil as cargo, broke in two in a severe storm in
the Bay of Biscay on 11 December 1999, 60 miles from the coast of
Brittany. About 20,000 tonnes of oil were spilled. The bow sank on 12
December and the stern on the following day.
The
French Naval Command in Brest took charge of the response operations at
sea in accordance with the French National Contingency Plan. Response
vessels were mobilised on 14 December, but attempts at skimming
ultimately met with little success owing to the poor weather and
widespread fragmentation of the slick.
In 15 days of operations 1,100
tonnes of oil/water mixture were collected, mainly during a 24-hour
period of relatively calm weather and reduced swell. It has been
estimated that less than 3% of the total spill volume was collected
during the response operations at sea.
Owing
to the influence of strong winds and currents, shoreline oiling did not
occur as quickly as expected or in the locations originally forecast.
After first moving south-east from the spill site toward La Rochelle,
then turning north, the oil finally began stranding around the mouth of
the River Loire on Christmas Day 1999.
Intermittent oiling subsequently
occurred over some 400km of shoreline between Finistère and
Charente-Maritime. Due to the long time that the oil spent at sea, much
of it formed a water-in-oil emulsion, which increased its volume and
viscosity.
The degree of oiling of shores was
very patchy through the affected area. The most heavily contaminated
areas were located in Loire Atlantique, the northern Vendée and on
offshore islands, notably Belle Ile.
These areas required the
mobilisation of considerable cleanup resources to carry out a programme
of initial bulk oil removal, followed by prolonged and difficult
secondary cleaning. Other areas received only very light oiling (eg
parts of Finistère and Morbihan) where fine cleaning alone was needed.
During
the cleanup operation, more than 250,000 tonnes of oily waste was
collected from shorelines and temporarily stockpiled. Temporary
reception facilities were established in car parks and stretches of
land close to beaches, mainly by building earth or sand bunds or
digging holes and lining them with plastic.
Ultimately, the French oil
company Total agreed to receive all the wastes at their Donges
refinery, where adequate storage sites were available within and close
to the refinery.
Little attention was paid to segregation of wastes,
however. The result was a mixture of oil, sand, debris, seaweed,
protective clothing, damaged booms and other response equipment like
scrapers, buckets and spades, which needed sorting before disposal
could proceed.
Operations to pump out oil
remaining in the sunken sections of ERIKA began once the weather
improved in June 2000 and were successfully completed within three
months. Some 10,000 tonnes of oil were recovered during the main
pumping operations. Fine cleaning added a further 1,200 tonnes.
The
main environmental impact of the spill was on sea birds. Almost 65,000
oiled birds were collected from beaches, of which almost 50,000 were
dead. A major cleaning operation was mounted for the 15,000 oiled
survivors and 2,000 were ultimately released.
The
magnitude of the spill and the length of coastline affected resulted in
a large number of compensation claims. There are important coastal
fisheries, mariculture (oysters and mussels) and tourism resources
throughout southern Brittany and the Vendée. Salt production areas were
also affected by oil pollution.
The Ievoli Sun was a chemical tanker
chartered by Napolitan ship-owner Luigi Ievoli. On 31 October 2000, she
sank at 49° 52 N et 002° 24 W, approximatively 9 miles off Casquets,
with a 6,000-tonne load, including 4,000 tonnes of Styrene, 1,000
tonnes of trichlorosilane and 1,000 tonnes of Isopropyl alcohol.
The wreckage was caused by bad weather,
and water intake at the bow, which filled the forware storage area and
the Bow thruster bay. The increase in weight caused a negative pitch,
which worsened while more compartments filled.
A distress call was received by the
CROSS at 04:30. At 07:17, a Super Frelon of the French Navy
departed to evacuate the 14-man crew of the tanker, amid 65-knot
(120km/h) winds. An hour later, the helicopter arrived on the scene,
and evacuated the crew in 40 minutes. The Abeille Flandre arrived and
started tugging the tanker at 4knots (7.4km/h) toward Normandy.
The next day in the morning, the Ievoli
Sun sank. The aviso Lieutenant de vaisseau Lavallée and the minesweeper
Céphée were sent on the scene to reinforce the Abeille Flandre and
monitor pollution. Only small traces of chemicals were noticed.
At
around 12:30 am on the night of 28 March 2001 during a storm in
the Baltic Sea (Beaufort 9 - very rough sea), the cargo vessel the
Tern collided with the oil tanker the Baltic Carrier, at the boundary
between the German and Danish territorial waters approximately 16
nautical miles southeast of the Danish islands Falster and Møn.
The
Tern rammed the Baltic Carrier in the bow, after veering off course
due to rudder failure and ripped open starboard cargo tank number
6 just in front of the bridge house. The Tern then proceeded to
the German port of Rostock under her own steam.
During
the course of the first few days following the collision, the bad
weather conditions hampered the Danish Coast Guard Authority’s
attempts to respond. Fifteen Danish, Swedish and German vessels
took to sea either to spot slicks or recover the oil. As the oil
was very viscous, mechanical diggers were just as efficient as standard
skimmers.
On Sunday 1 April, 940 tonnes were recovered at sea. Airborne
and satellite-based surveillance was maintained from the outset.
Unlike the Erika incident, weather conditions enabled the satellites
to spot the slicks and the footage was made available by ESA, the
European Space Agency.
Initial
emergency clean-up was performed under the responsibility of the
Danish Civil Defence that opted for heavy duty machinery and equipment
requisitioned from local companies and in particular from construction
companies (diggers, bulldozers, tippers, suction tanks).
It is important
to point out that substantial quantities of oil were recovered by
the end of day 3 (2,000 tonnes). But the physical impact on the
upper foreshores and on the banks was considerable, partly due to
the fact that many of the banks were in the high tide zone and therefore
very sensitive.
Environmental deterioration could have been lessened
if the authorities had opted to pump the oil, in view of the fact
that weather conditions at the time were favourable for the onshore
response phase.
Task Force experts came to the conclusion that approximately 50
km of coastline had been polluted and in some areas the slicks were
very thick, especially in the small coves. The areas in question
were marshlands and pebble beaches.
The response conducted on the
beaches involved using a bulldozer to remove a layer of polluted
pebbles and of transferring them by lorry to a washing station (disused
quarry). The pebbles were washed with water and surfactant and put
back on their original beach.
During the afternoon of Wednesday 13 November 2002,
the tanker Prestige (81,564 DWT), carrying a cargo of 77,000 tonnes of
heavy fuel oil, suffered hull damage in heavy seas off northern Spain.
She developed a severe list and drifted towards the coast, and was
eventually taken in tow by salvage tugs.
The casualty was reportedly
denied access to a sheltered, safe haven in either Spain or Portugal
and so had to be towed out into the Atlantic. Although attempts were
made by salvors to minimise the stresses on the vessel, she broke in
two early on 19 November some 170 miles west of Vigo, and the two
sections sank some hours later in water two miles deep. In all, it is
estimated that some 63,000 tonnes were lost from the Prestige.
Owing
to the highly persistent nature of Prestige's cargo, the released oil
drifted for extended periods with winds and currents, travelling great
distances.
Oil first came ashore in Galicia, where the predominantly
rocky coastline was heavily contaminated. Remobilisation of stranded
oil and fresh strandings of increasingly fragmented weathered oil
continued over the ensuing weeks, gradually moving the oil into the Bay
of Biscay and affecting the north coast of Spain and the Atlantic coast
of France, as far north as Brittany.
Some light and intermittent
contamination was also experienced on the French and English coasts of
the English Channel. Although oil entered Portuguese waters, there was
no contamination of the coastline.
A major
offshore cleanup operation was carried out using vessels from Spain and
nine other European countries. The response, which was probably the
largest international effort of its kind ever mounted, was hampered by
severe weather and by the inability of those vessels that lacked cargo
heating capability to discharge recovered oil.
Over a thousand fishing
vessels also participated in the cleanup in sheltered coastal waters
and during favourable weather. As some of the oil moved into French
waters, control of a reduced at-sea recovery operation passed to the
French authorities.
The open-sea recovery
operation off Spain reportedly removed almost 50,000 tonnes of
oil-water mixture. However this, and the extensive booming of estuaries
and sensitive areas by the deployment of over 20km of boom, failed to
prevent extensive coastal contamination.
Altogether approximately 1,900
km of shoreline were affected. The shorelines of Spain were largely
cleaned manually by a workforce of over 5,000 military and local
government personnel, contactors and volunteers.
The process was slow,
especially in rocky areas where access was difficult. A further problem
was re-oiling of previously cleaned areas by re-mobilised oil. On the
French Atlantic coast the beach contamination took the form of numerous
tar balls which were relatively easy to remove. In total, some 141,000
tonnes of oily waste was collected in Spain and 18,300 tonnes in France.
Fisheries
exclusion zones were put in place in Galicia shortly after the
incident, banning virtually all fishing along about 90% of the
coastline. All bans had been lifted by October 2003. The impact on
fisheries in France was less extensive. In both countries, an impact on
tourism was reported for 2003.
The Spanish
authorities decided to remove the oil remaining in the wreck. The work
commenced in May 2004 and was finalised in September 2004 at an
estimated cost of some €100 million.
The Maltese tanker Tasman Spirit (87,584 DWT)
grounded at the entrance to Karachi Port, Pakistan in the early hours
of Sunday 27 July 2003. The vessel was carrying 67,800 tonnes of
Iranian Light crude oil destined for the national refinery in Karachi.
There were also 440 tonnes of heavy fuel oil in aft bunker tanks. The
condition of the grounded tanker deteriorated as she was subjected to
continuous stress from the heavy swell of the prevailing south-west
monsoon and the vessel subsequently broke in two. In total, it is
estimated that some 30,000 tonnes of oil was spilled from the Tasman Spirit.
In the course of inspections on board the Tasman Spirit it became apparent that most of the cargo tanks had been
ruptured, whilst the bunker tanks remained intact.
The owners appointed
salvors and also hired a succession of small tankers and barges for the
purpose of shuttling and storing oil lightered from the casualty.
During the next few weeks roughly half of the crude oil cargo and most
of the bunker fuel was successfully transferred from the casualty.
On 11 August the tanker began to show signs of
breaking up and eventually broke in two overnight on 13/14 August,
spilling several thousand tonnes of crude oil. Much of the spilled oil
quickly stranded on Clifton Beach, the main tourist beach in Karachi,
but significant quantities remained afloat both inside and outside
Karachi port.
Dispersants were applied offshore from a Hercules C-130
aircraft equipped with an aerial dispersant spraying system (ADDS Pack)
in response to two distinct pollution events involving the progressive
break-up of the tanker. Approval for large scale dispersant use was
given by the Karachi Port Trust (KPT) and the Pakistan Environment
Protection Agency.
Oil entering the port of Karachi was confined by
deploying booms at suitable collection sites, and in total some 140
tonnes of oil were recovered by skimmers. KPT also deployed vessels to
apply dispersant on oil drifting through the port entrance.
The severe pollution of Clifton Beach created very
strong oil vapours causing considerable discomfort to local residents
and clean-up personnel. Local hospitals reported many cases of
headaches, nausea and dizziness and seventeen schools in the vicinity
were closed for about a week.
The beach was cleaned by a combination of
manual and mechanical means, but work was hampered by a lack of
suitable disposal sites for collected oily waste. Agreement was
eventually reached for disposal at one of the municipal waste sites
serving Karachi City. Clifton Beach was re-opened to the public in the
middle of October.
Given the low persistence of Iranian Light crude oil
and the high mixing energy in the many damaged cargo tanks generated by
the incessant heavy swell, it is likely that most of the spilled oil
dispersed naturally. Field surveys conducted showed little or no impact
on mangroves, salt pans and other sensitive resources in the vicinity.
The geographical extent of shoreline oiling was limited to a ten-mile
radius around the grounded tanker.
Whilst there were few reports of repercussions of
the oil on fisheries, a three-month fishing ban was imposed by the
Marine Fisheries Department along the coastline directly affected by
oil, extending five nautical miles offshore.
At 18051 on Saturday, 28 February
2004 the chemical tanker Bow Mariner caught fire and exploded while the
crew was engaged in cleaning residual Methyl Tert Butyl Ether (MTBE)
from cargo tank number eight starboard. The ship sank by the bow at
1937 about 45 nautical miles east of Virginia.
Of the 27
crewmembers aboard, six abandoned ship and were able to make it to an
inflatable life raft and were rescued by the Coast Guard. An unknown
number of other crewmembers abandoned ship to the water.
The Coast
Guard and Good Samaritan vessels recovered three of these crewmen from
the water, one deceased. The other two died before reaching a hospital.
18 crewmen remain missing and are presumed dead.
Before
the explosion the Bow Mariner was carrying about 3,188,711 gallons of
ethyl alcohol, 192,904 gallons of HFO, 48,266 gallons of LFO and an
unknown quantity of slops. Immediately after the sinking a heavy,
circular oil slick, about two miles in diameter, was recorded by a
Coast Guard aircraft using an infrared video recorder.
The Coast Guard
and responsible party conducted over flights for several days following
the sinking, and observed an oil slick up to 35 miles long and 1.5
miles wide.
Rescuers and survivors reported
a heavy, alcohol-like odor, causing nausea, dizziness and headaches in
some of the people exposed to the fumes. All of the survivors and
bodies recovered were coated with HFO and smelled of alcohol. Taken
together this indicates that some, if not all, of the ethyl alcohol was
released.
Because ethyl alcohol is completely soluble in water and not
regulated as a NLS, further effort to recover any ethyl alcohol that
was not released was not attempted.
The cause of this casualty was the ignition of a fuel/air mixture,
either on deck or in the cargo tanks, that was within its flammable
limits. The ignition source could not be precisely determined.
Contributing to this casualty was the failure of the operator, Ceres
Hellenic Enterprises, Ltd., and the senior officers of the Bow Mariner,
to properly implement the company and vessel Safety, Quality and
Environmental Protection Management System (SQEMS).
Source: www.wwf.org.uk ; www.incidentnews.gov ;
www.cedre.fr ; www.c4tx.org ; www.evostc.state.ak.us