Written by  Émilie St-Hilaire,Four Green Steps

This is the most recent of our ten worse environmental disasters, as it happened only a little over two years ago, on April 20, 2010.  It was not the first oil spill in the United-States, but it certainly was the biggest. It has been estimated that a total of 4.9 million barrels of oil were spilled in the Gulf of Mexico. At a price of $81.17 per barrel, the spill was worth 397.7 millions. About 665 miles of shoreline was affected in the states of Louisiana, Mississippi, Alabama and Florida.

The Deepwater Horizon platform was situated 50 miles from the Mississippi delta. On April 20th, 2010, there was an explosion due to a leak of oil reaching the deck above the water level. The cement that usually prevented oil to leak from the pipe was not adhering properly. After the explosion, the platform detached itself from the pipe, sank 5000 feet down the Gulf of Mexico, releasing millions of gallons of oil, as the blowout-preventer failed to be activated to stop the leak.

Many attempts to reduce the flow failed. It is only in the beginning of August that the flow was completely stopped, using a mud-pumping method to block the leak, called “static kill”.  It was completely and permanently sealed on September 19th.

Booms have been used to absorb oil and prevent it from getting to land. Some controlled fires managed to clean millions of gallons of oil. 1.84 million gallons of dispersants have been used to emulsify the oil.  The dispersants do not however clean up the oil; it only breaks out the big mass of oil in smaller pieces scattered through water. The dispersants contain powerful chemicals which many are toxic and can accumulate in organisms.

The leak of oil in the Gulf harmed many organisms, as the region hosts one of the greatest ecosystems that is home to many species from which 32 are already endangered or threatened. After the spill, birds and sea turtles were found dead, covered in oil. The ingestion of oil damaged the inner organs and the immune system. Algae and phytoplankton could have been contaminated by oil; being at the bottom of the food chain, it could contaminate the entire ecosystem.

Oysters and dead deepwater corals are also a concern, as they might need a longer period of time to reach their original population numbers. One third of the Gulf of Mexico has been closed to fishing, to let fish and marine species recover from the spill. Louisiana’s coastal wetlands have suffered further damage from the oil spill, as they were already vulnerable to human activity and hurricanes. These wetlands are home to many animal populations, act as a storm buffer, and help preventing floods.

Tar balls (clumps of weathered oil and sand) are still collected on some beaches, meaning that an important percentage of oil still remains in the water. The Gulf of Mexico is however expected to recover fast.Restore the Gulf.gov presents the progress of the restoration of the Gulf and coastlines

Image courtesy of Creative Commons.

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