An explosion and fire aboard the Deepwater Horizon drilling rig, operating on BP's Macondo prospect, killed eleven crew members and sank the vessel two days later.

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Attempts to seal the well took 87 days, during which an estimated 4.9 million barrels of oil entered the Gulf of Mexico, fouling Louisiana marshes and closing large areas of fishery. Live video of the leaking riser became a nightly fixture on American television.

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BP eventually agreed to settlements and penalties totalling tens of billions of dollars, and United States offshore drilling regulation was substantially rewritten in the aftermath.