Disasters on offshore oil and gas rigs are not just measured by the loss of human life. Some can cause untold damage to ecosystems for decades, not to mention the amount they cost to clean up.
While the Exxon Valdez and Amoco Cadiz are synonymous with shipping disasters, incidents involving offshore rigs can be even more devastating.
Deepwater Horizon has claimed 11 lives and news organisations are estimating the clean-up bill may run into billions.
To put Deepwater Horizon in perspective we chart the recent history of offshore rig disasters.
1964 CP Baker Drilling Barge, Gulf of Mexico
Lives lost: 22
Operator: Pan American Petroleum Corporation
The first major offshore disaster in the world occurred when a blowout engulfed the CP Baker barge in fire. Many of the crew jumped to safety into the sea but 22 died. The ship was a catamaran, and the force of the blowout causing an eruption in the water between the hulls.
1965 Sea Gem, North Sea
Lives lost: 13
Operator: British Petroleum
Metal fatigue was blamed for the sinking of the first operational oil well in the North Sea. Two of the ten rig legs failed causing the rig to fall sideways before sinking.
Some of the crew were able to escape on life rafts, others on a passing boat called the Baltrover. The remainder jumped into the freezing ocean and perished.
1969 Platform Alpha, Santa Barbara Channel, US
Oil leaked: 80,000 Barrels of Oil
Company: Union Oil
The 11-day blowout on Platform Alpha leaked oil into the sea off the California coastline.
After the devastation was realised, the US Government put environmental legislation in place to protect against such disasters. This shaped the future for the legislative environment for offshore oil and gas in the US.
1976 Ocean Express, Gulf of Mexico
Lives lost: 13
Deteriorating sea conditions caused the Ocean Express to leak while being towed to a new location.
The coastguard was called in to evacuate people aboard the rig while some of the crew were evacuated in survival capsules. One of the capsules, carrying 20 men, overturned in the heavy seas and started to flood. Only seven men were able to escape.
1977 Ekofisk Bravo, Norwegian Continental Shelf
Oil leaked: 202,000 barrels
Company: Phillips Petroleum (now ConocoPhillips)
The blowout occurred when the crew were removing 10,000ft of production tubing from the Ekofisk Bravo. According to reports, the Christmas-tree valve stack had been removed before the blowout preventer had been installed.
It took seven days to cap the well. This was the first major oil spill in the North Sea.
1979 Bohai 2, Gulf of Bohai, China
Lives lost: 72
Company: China Petroleum Department
Storm-force winds broke a ventilator pump on the Bohai 2, punching a hole in the deck floor and flooding the pump room. The jack-up, which was being towed at the time, subsequently sank, killing 72 out of the 74 workers on board.
Sedco 135F, Behia de Campeche, Mexico
Oil leaked: 3.5 million barrels
Company: Petroleos Mexico (Pemex)
Reports of the accident on the Sedco 135F claim mud circulation, used as a lubricant for the drill, was lost so it was decided to pull the drill string and plug the well. Complications meant oil and gas rose to the surface and ignited causing the rig to sink.
1980 Edda, Norwegian Continental Shelf
Lives lost: 123
Company: Phillips Petrolium
Gale-force winds broke the braces attaching the Alexander L Kielland floating hotel to the Edda’s legs, causing it to flood.
Lifeboats were smashed against the rig’s legs and many of the men were swept away. Only 89 of the 212 men onboard survived.
Funiwa 5, Niger Delta
Oil leaked: 200,000 barrels
The blowout from the Funiwa 5 polluted the mangrove forests of the Niger Delta for two weeks. It eventually ignited, burning off much of the excess oil.
According to the Niger Delta Congress as many as 230 people died as a direct result of the pollution caused by the blow out.
Hasbah Platform, Persian Gulf
Lives lost: 19
Oil leaked: 100,000 barrels
While being drilled by the Ron Tappmeyer Dillship, the Hasbah Platform blewout after a pocket of hydrogen sulphide gas was hit.
It took eight days before the Persian Gulf well was capped. Efforts to control the discharge where hampered by the release of hydrogen sulphide.
1982 Ocean Ranger, North Atlantic
Lives lost: 84
During a major storm, rigs noticed the Ocean Ranger was listing. Despite the efforts of standby vessel Seaforth Highlander, many crew members died due to exposure.
The US Coastguard’s report concluded waves broke a portlight causing areas of the rig to flood.
1983 Glomar Java Sea Drillship, South China Sea, China
Tropical Storm Lex caused the US-built Glomar Java drillship to capsize and sink killing all crew, although fewer than half of the bodies were recovered.
1984 Enchova Central, Campos Basin, Brazil
Lives lost: 42
Cost: $461m in lost revenue and clean-up costs
A blowout at the Enchova Centra well caused an explosion and fire.
All the deaths occurred during the evacuation with 36 killed when a lifeboat’s cables snapped as it was being lowered into the sea. Another six died jumping from the platform.
In 1988 another blowout destroyed the rig entirely but without any fatalities.
1987 Steelhead Platform, Cook Inlet, Alaska
Cost: $197m in lost revenue and clean-up costs
A natural gas blowout caused the top of the Steelhead Platform to catch fire causing extensive damage to the helipad, accommodation module, one of the cranes and the drilling module.
All members of the crew were able to escape in the lifeboats. Over the following six months the well suffered two more blowout’s delaying the start of production.
1988 Piper Alpha, North Sea
Lives lost: 167 including two rescuers
Cost: $1.27bn in lost revenue and clean-up costs
A breakdown in command was blamed for the accident on Piper Alpha that killed 167 people.
A gas condensate leak ignited, leading to further leaks and explosions.
The number of fatalities was exacerbated by the failure of the company to upgrade the blast walls when the rig started to pump natural gas instead of oil.
1989 Seacrest Drillship, South China Sea, Thailand
Lives lost: 91
Heavy seas caused by Typhoon Gay apparently capsised the Seacrest Drillship. Seacrest sent no distress calls and the cause of the accident is unknown.
News agencies around the world have since reported between four and seven crew members may have survived.
1990 Sleipner A, Norwegian Continental Shelf
Cost: $365,000,000 in lost revenue and clean-up costs
The concrete deep-water platform sank after a cell wall cracked while it was being lowered. When the buoyancy chambers imploded on Sleipner A, rubble striking the shelf floor caused a local seismographic station to record a 3.0 experience.
Underestimated ballast chamber stresses were blamed for the accident.
1998 Petronius A, Gulf of Mexico
Cost: $116m in lost revenue and clean-up costs
During construction of the Petronius A, a crane load line broke causing the south deck module to strike the transport barge before sinking to the seabed.
The facility eventually went online in 2000 but was later damaged by Hurricane Ivan in 2004.
2001 P-36, Campos Basin, Brazil
Lives lost: 11 including one firefighter
Cost: $515m in lost revenue and clean-up costs
Two explosions in the emergency drain tanks caused the P-36, originally called Spirit of Columbus, to sink with an estimated 9,500 barrels of oil on board. Rescue teams unsuccessfully attempted to pump nitrogen into the legs to keep it afloat.
Of the 175 crewmembers, 138 were evacuated by crane to a rescue boat.
2005 Mumbai High North, Indian Ocean
Lives lost: 22
Cost: $195m in lost revenue and clean-up costs
Company: Oil and Natural Gas Corporation
While transferring an injured cook to the Mumbai High North the support boat MSV Samudra Suraksha collided with the gas export risers causing an explosion.
The cook was being transferred by ship because monsoon conditions on land had forced all helicopters to be grounded.
The location and protection of the risers was criticised after the tragedy.
There were 384 personnel on board at the time with 11 reported missing and presumed dead. Six divers on the support boat were in a saturation chamber at the time and were rescued 36 hours later.
2007 Perforadora Central Usumacinta, Gulf of Mexico
Lives lost: 22
Company: Petroleos Mexicanos
Storm winds in the Gulf of Mexico caused a gas leak on Usumacinta, which the crew were unable to contain. Lifeboats saved 81 members of the crew.
In the aftermath PEMEX was criticised for using chemical dispersants to get rid of the crude oil on the sea surface, causing it to sink to the sea bed instead.
Over the next month the rig caught fire twice more but without any casualties.