Tanker Incidents

1967. - Torrey Canyon

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.

1972. - Sea Star

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.

1974. - Metula

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.

1978. - The Amoco Cadiz

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.

1979. - Ixtoc I

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.
1979. - Burmah Agate

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.

1989. - Exxon Valdez

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.


1989. - Kharg 5

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.

1990. - American Trader

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.

1990. - Megaborg

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.


1992. - Aegean Sea

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.

1993. - Braer

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.

1996. - The Sea Empress

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.

1999. - Erika

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.

2000. - Ievoli Sun

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.

2001. - Baltic Carrier

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.

2002. - Prestige

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.

2003. - Tasman Spirit

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.

2004. - Bow Mariner

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