The Gulf of Mexico (Spanish: Golfo de México) is an ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In Texas and Louisiana it is often called the "Third Coast," in comparison with the U.S. Atlantic and Pacific coasts. The shape of its basin is roughly oval and is approximately 810 nautical miles (1,500 km) wide and filled with sedimentary rocks and debris. It is connected to the Atlantic Ocean through the Florida Straits between the U.S. and Cuba, and with the Caribbean Sea (with which it forms the American Mediterranean Sea) via the Yucatan Channel between Mexico and Cuba. With this narrow connection to the Atlantic, the Gulf experiences very small tidal ranges. The size of the Gulf basin is approximately 615,000 mi² (1.6 million km²). Almost half of the basin is shallow continental shelf waters. At its deepest it is 14,383 ft (4,384 m) at the Sigsbee Deep, an irregular trough more than 300 nautical miles (560 km) (550 km) long. The basin contains a volume of roughly 660 quadrillion gallons (2.5 × 106 km3). It was formed approximately 300 million years ago as a result of plate tectonics.
The Deepwater Horizon oil spill (also referred to as the BP oil spill, the BP oil disaster, the Gulf of Mexico oil spill, and the Macondo blowout) was an oil spill in the Gulf of Mexico on the BP-operated Macondo Prospect, considered the largest accidental marine oil spill in the history of the petroleum industry, estimated to be between 8% and 31% larger in volume than the earlier Ixtoc I oil spill. Following the explosion and sinking of the Deepwater Horizon oil rig, which claimed 11 lives, a sea-floor oil gusher flowed unabated for 87 days, until it was capped on 15 July 2010. The total discharge is estimated at 4.9 million barrels (210 million US gal; 780,000 m3).
A massive response ensued to protect beaches, wetlands and estuaries from the spreading oil utilizing skimmer ships, floating booms, controlled burns and 1.84 million US gallons (7,000 m3) of Corexit oil dispersant. After several failed efforts to contain the flow, the well was declared sealed on 19 September 2010. Some reports indicate the well site continues to leak. Due to the the months-long spill, along with adverse effects from the response and cleanup activities, extensive damage to marine and wildlife habitats, fishing and tourism industries, and human health problems have continued through 2013.