Oil is insoluble in water but it can still cause a ton of adverse effects on marine life and sea creatures if spilt in water. There have been many incidents where oil barrels have spilled into the sea, the reason could be either human error or an unfortunate accident, but the Deepwater Horizon oil spill was the largest one in history.


Also known as the Gulf of Mexico oil spill occurred on the 29th of April in 2010 at the Deepwater Horizon oil rig located in the Gulf of Mexico. The cause was identified as an explosion that toppled or capsized the oil rig and led to the leakage of oil which was later estimated by British Petrochemical Corporation (BP) to be around 1000 barrels a day and United States’ officials later stated that it had peaked to about 60,000 barrels a day.

Owned and operated by Transocean (an off-shore oil drilling company), the Deepwater Horizon Oil Rig was leased by BP. It was located on the continental shelf of Mississippi Canyon.  The cause of the leak was a surge of natural gas through a concrete core to seal the well, that had recently been installed by a contractor. A similar spillage had been reported in 2008 in a BP-owned rig in the Caspian Sea. In both cases, it was detected that the cores were too weak to contain the pressure and that the rigs were operated by BP.

Once being able to get released from the core, the gas travelled through the rig’s riser to the platform and got ignited which caused 11 causalities and injuring almost 17 people. The rig shrank and drowned in the water and oil began to discharge into the Gulf of Mexico. The loss was valued at thousands of barrels of oil per day.


Many methods and procedures were used to prevent the oil from spilling further and also containing the flow of the oil still rupturing from the rig. The immediate response to the explosion was the activation of the rig’s blowout preventer (BOP) by BP, a mechanism made to close the channel through which the oil is being drawn. But it failed due to some former damage. Although a US Chemical Safety Board study later claimed that the BOP had been activated earlier than thought out and might have punctured the pipeline.

A containment dome was supposed to be built over the entire area of the spill, but the buoyancy of gas hydrates- formed due to a reaction between natural gas and cold water was a barrier in the construction of the dome. To reduce the amount of oil spilling out of the pipe, a “top kill” which is a procedure to gain control over an oil well that is erupting uncontrollably, was applied. Mud was pumped into the well to reduce the flow of the oil, but it did not make any difference, after which the BP decided to fit in a Lower Marine Riser Package (LMRP) cap. This allowed approximately 15,000 barrels of oil to be pumped into a separate tank. Although some leakage was still there, the collection rate increased to almost 25,000 barrels of oil per day.

Through this method, almost 800,000 barrels of oil were captured. But on the other hand, scientists reported that 4,900,000 barrels of oil had been spilled into the Gulf. Gradually, as the flow of the leakage reduced, the “static kill” method was put into place. Similar to the top kill, it pumped mud into the well through the blowout preventer, but it was at a much lower pressure as the capping stack had now stabilized. The success of static kill paved way for the final step “bottom kill”, which is the pumping of cement into the well to permanently seal the leak.


The leaked oil had spread over an area of 149,000 square kilometres in the Gulf of Mexico. 1.8 million “dispersants” that are substances that emulsify oil, making it easier to clean up were pumped directly onto the oil spill. The oil was then collected or even burned off. The more difficult areas to clean were the 1770-kilometre-long shoreline of the US that was affected and polluted by the spill. Owing to the topography and the complicated plant life, it had to be cleaned manually in these areas.

The US Department of Justice (DOJ), sued BP, Transocean, and Anadarko a minority owner of the well, for violation of the Clean Water Act and Oil Pollution Act in New Orleans civil court in 2010. The case went on for a few years, by the end of which a settlement was agreed on. The agreement resulted in penalties and fines totalling up to $4.5 billion, out of which almost $1.26 billion would be given to a discretionary fund under DOJ, almost $2.4 billion to the National Fish and Wildlife Foundation and $350 million to the National Academy of Sciences. The majority of penalties were paid by BP, but Transocean and Anadarko also had to pay damages.


Many animals including sea creatures and even birds were found covered in oil and the environmental impact was immense. Several dolphins were found dead due to the spill and some even have infertility issues to date. Around 1400 mammals like whales and dolphins were found stranded after almost 7 years of the spill. And these numbers were only a fraction of the population of sea creatures that were affected.

Birds were also impacted, as many of the species in that area dived into the sea to procure food and water. The brown pelican, an endangered species, was one of those who bore the brunt of the accident. A 2014 study revealed that almost 800,000 birds had died as an aftermath of the spill. The sea turtles were also affected and in 2012, a study showed that almost 1700 turtles had died. Many including the endangered species of Kemp’s Ridley sea turtles were severely affected.

The impact could also be seen on the smaller species of fish and sea mammals. Studies revealed that many commercially imported fish species including tuna developed heart defects after being exposed to certain enzymes in the oil. Coral reefs’ reproductive health suffered from adverse effects. The oil was also harmful to the microorganisms and bacteria in the sea.


Many economies in the Gulf area and many residents were dependent on industries that were related to the Deepwater oil rig. A moratorium or delay of proceedings by the Obama administration left almost 12,000 people without a job. Tourism declined to many beaches on the shoreline impacted by the spill. Even after months of clean up, oil would still get washed up to the shore.

BP was also adversely impacted in business after the spill. Following the settlement of the lawsuit, BP has lost almost 1/4th of its market value and had already paid over $40 billion in damages. They had also lost the right to drill oil in many rigs owned by the US government. Therefore, it can be seen from this incident that a small human error can lead to grave consequences to not only mankind but also animal life and can incur huge economic costs as well. Regret and compensation is only one way of dealing with it, the more sustainable solution comes in the form of lessons learned in hindsight and mistakes not repeated again.


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