The largest accidental marine oil spill in human history took place in the Gulf of Mexico in the year 2010. The incident resulted after methane gas was released and exploded in the BP-owned Macondo exploration well on Apr 20, 2010. The fire continued for 36 hours and the oil drilling rig (Deepwater Horizon) sank on Apr 22. This incident led to the loss of 11 lives and the spill of about 4.9 million barrels of oil. The oil spill affected as much as 68,000 square miles. After extensive efforts, the well was capped after 87 days (on 15 July 2010) and sealed on 19 September, 2010.
Control and remediation measures were immediately started with BP compensating for the entire effort. Measures were taken to seal the well (control of source) and prevent the spread of oil on water, into the ocean and onto the beaches. At its peak, the efforts involved about 48,000 people and 6,500 vessels. Among the containment and control measures, the use of a containment boom, controlled combustion and Corexit dispersant were the most common. Despite these efforts, it has been estimated that almost 75% of the oil spill is still unaccounted for. The clean up efforts were stopped in April 2014.
The spill caused economic and environmental issues. BP has spent almost $14 billion on clean-up and response activities (as of December 2014). Additional cleanup costs may be required in the future and the company may still have to pay fines, costing several more billions dollars. Additionally, BP has been temporarily banned from seeking new governmental contracts. Give this high cost, the future of company is uncertain. Apart from BP, the local community is also suffering the economic downturn. Oil-drilling and exploration work has been stopped and due to the oil spill, fishing is also banned in a large tract of ocean. Among environmental impacts, marine organisms are the most important. Increased lesions on fish have been reported as has the high incidence of deformed fish and other marine organisms. Dolphins have also been impacted and increased mortality of infant dolphins have been observed. The oil spill has covered a large area and has been washed on to the beaches as well.
Overall, this spill has damaged the environment extensively (and according to some estimates, is still doing so) and affected the economy of the region, not to mention the future of BP.