Environmental Implications of Oil Spills

Henry Hirshland
November 24, 2016

Submitted as coursework for PH240, Stanford University, Fall 2016


Fig. 1: Annual number of dolphin deaths in the Gulf of Mexico. [3] (Source: H. Hirshland)

Throughout history we have witnessed several catastrophic oil spills. These oil spills have had negative effects on both our environment and our economy. While these oil spills are devastating in many ways, for some reason the public has historically lost interest in them immediately after they have come to completion, even though their impacts do not go away. It is also important to note that while the public tends to hear about huge oil spills like the Deepwater Horizon spill, the media does not typically cover most oil spills, and they go unnoticed by the public eye. Yet, there are many oil spills each year that have significant impacts on the environment.

Environmental Issues

On April 20, 2010 the Deepwater Horizon oil rig exploded, leaving the well uncapped with oil flowing out of it freely for 87 days. [1] It was flowing at a rate of around over 50 million gallons a day. It is estimated that a total of 4.9 million barrels of oil leaked into the Gulf of Mexico, where the Deepwater Horizon was located. [2] That is approximately 205.8 million gallons. This damaged sea coral and disrupted the marine ecosystem. The oil spill caused direct harm to marine animals in ways that can be easily observed. For example, tons of seabirds found themselves covered in oil, or stuck in the sludge. The stranding of various species also increased significantly. According to a recent study, the BP oil spill in 2010 can be directly related to the record number of dolphin deaths in the Gulf of Mexico. While BP has claimed these deaths were due to respiratory diseases, scientists have demonstrated they suffered from lung and adrenal lesions caused by swimming in oil-contaminated waters. [2]

According to a report conducted in 2015, "From 2002 to 2009, the Gulf averaged 63 dolphin deaths a year. That rose to 125 in the seven months after the spill in 2010 and 335 in all of 2011, averaging more than 200 a year since April 2010". [2] Fig. 1 shows the upward trend of dolphin deaths in the Gulf following the oil spill.


In conclusion, it is important that we understand the environmental implications of oil spills to raise awareness and prevent future mishaps. Many of the effects are long lasting and irreversible. The positive news is that the total number of annual oil spills has decreased significantly over time. Hopefully, as awareness of oil spills increases we will see this trend continue in the right direction.

© Henry Hirshland. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] "Assessment of Flow Rate Estimates for the Deepwater Horizon / Macondo Well Oil Spill," US Department of the Interior, March 2011.

[2] J. Achenbach and D. Fahrenthold, "Oil Spill Dumped 4.9 Million Barrels into Gulf of Mexico, Latest Measure Shows," Washington Post, 3 Aug 10.

[3] "Scientists Link Dolphin Deaths in Gulf to 2010 BP Spill," Chicago Tribune, 20 May 15.