It claimed the lives of 11 workers, soiled the coastline of five American states and sent as many as 4.9 million barrels of oil gushing into the Gulf of Mexico. The BP well blowout was the largest accidental oil spill in history.
BP engineers have stopped oil from leaking into the Gulf and are in the final stages of drilling a relief well that is expected to end the disaster for good, months after the Deepwater Horizon rig exploded on April 20. The US president Barack Obama vowed on Saturday to stand by residents affected by the spill until the area's environmental health is fully restored. As he began a brief family vacation in the region, Mr Obama met business owners and officials.
"I'm here to tell you that our job is not finished, and we're not going anywhere until it is," he said. Sealing the Macondo well marks an end to a chapter that stained BP, left fishermen, shrimpers and hoteliers out-of-pocket and spawned imaginative uses for golf balls, car tyres and deep-sea robots. The leak took on political dimensions, testing the "special relationship" between the United States and the United Kingdom - home of the petrochemical firm previously known as British Petroleum - and ignited an old row about the early release of the Libyan jailed for his role in the bombing of Pan Am 103.
Question marks now hang over the regulation of offshore deepwater oil drilling, and US courtrooms will face a flurry of cases involving rig workers, victims of the pollution, BP and other firms connected to the leak. "The Exxon Valdez oil spill in Alaska occurred in 1989 and we're still hearing about it today," said Nick Loris, an analyst from the Washington-based think tank The Heritage Foundation. "Now the Gulf oil spill is going to be turned over to the courts - and it's going to take a long time to work out exactly what went wrong, who to blame and who deserves to be compensated."
The Deepwater Horizon rig, owned by Transocean and leased to BP, was stationed 66km off the Louisiana coast and was drilling some 1,500m below sea level when an explosion ripped through it. A surge of natural gas blasted through a concrete cap and sped up the rig's riser to the platform, where it ignited - killing 11 workers and injuring 17 more. The platform collapsed and sank two days later, damaging the well and opening a massive crude gush into the Gulf.
A growing slick covered thousands of square kilometres of sea before washing up on beaches, estuaries and marshland - hitting Louisiana on May 20 and eventually soiling more than 1,000km of coastline across five states. BP officials looked like bumbling amateurs as they struggled to plug the leak, first with a 100-tonne steel and concrete cap, then a "junk shot" of golf balls, tyres and mud inserted by deep-sea robots.
BP apparently took risks to cut costs during drilling. The company's emergency response plan was lampooned because it featured a dead wildlife expert and rescue methods for walruses, sea otters and other animals that are not native to the Gulf. The BP chief executive Tony Hayward assured Americans that BP would "deal with the leak" but he ended up causing a public relations fiasco. On May 30 he declared to reporters that he "would like my life back". In June he went yachting with his son.
He was pilloried in the media and, during a fiery session of a congressional energy panel, was accused of ignoring safety warnings, shirking responsibility and presiding over "astonishing" corporate complacency. He announced his resignation last month and will step down in October. Aware of his predecessor's weak response to Hurricane Katrina of 2005, Mr Obama got tough and told Americans he was looking for "whose ass to kick", eventually getting BP to agree to a US$20 billion (Dh73bn) victims' compensation fund.
Claims are already expected to exceed the fund, which itself marks only part of the $32.2 billion costs BP predicted on July 27. The firm scrapped dividend payouts for 2010, began selling assets and watched share values plummet, including a 17 per cent fall on a single day, June 1. Hostility to what many Americans saw as a "British firm" strained relations between the allies, with Boris Johnson, the London mayor, hitting out at "anti-British rhetoric". Last month, it soured David Cameron's first visit to Washington since he became the British prime minister.
The transatlantic spat resurrected arguments about the release of Abdelbaset al Megrahi from jail in Scotland for his part in the destruction in 1988 of Pan Am Flight 103 as it flew over Lockerbie, Scotland, en route to New York, killing 270 people, mostly Americans. US politicians demanded to know whether Scotland's decision to release the Libyan last year had anything to do with BP gaining access to Libya's oil fields.
Although countless fish perished in the slick and thousands of oil-coated birds, mammals and turtles died or needed rehabilitation, early fears of environmental "oilpocalypse" were not realised. A US report this month said 74 per cent of the estimated 4.9 million barrels of released oil was skimmed, burned, evaporated, dissolved, recovered at the wellhead or dispersed - either naturally or with chemicals.
Earlier this month, engineers stopped the leak with a "static kill" operation. They stopped the flow by pumping heavy mud into the well. They later sealed it with cement. The ultimate solution - a relief well - is expected to be completed later this month. That still leaves a Justice Department investigating on several fronts, including criminal and civil violations of environmental laws on top of the many expected lawsuits from affected individuals and businesses.
Meanwhile, Americans are still grappling with the future of offshore drilling. Proponents want business to flourish unimpeded and opponents cite the potential damage from spills and global warming. Brad Johnson, an analyst from the Center for American Progress, said the "Obama administration has learned that offshore oil drilling is not as safe or reliable as the oil industry claimed it was" and praised the government's moratorium.
"One hopes that people take the fundamental lesson that the best thing to do with deepwater oil is to figure out ways to keep it underground," he said. "Every oil well that we don't have to drill is a guarantee that a disaster like this won't happen again." Others, such as the energy and environment expert, Mr Loris, presented the other side of an argument. "It's hard to see the silver lining on an environmental disaster like this, but it shows how we need to put in place a workable policy that properly balances the risks and behaviour of these companies," he said. "We don't want to drive them off to other countries or out of business unnecessarily because they will be subject to frivolous lawsuits."