Oil Spill: How Does it Happen and Various Causes of Oil Spill

What is Oil Spill?

Oil spills are leakages or spillage of petroleum and their byproducts into the environment particularly onto the surface of large water bodies such as oceans, lakes and rivers as a result of human activities. For this reason, oil spill is regarded as a form of pollution as the term is mostly applied to define spillage of oil in marine systems. Oil spills may occur on land as well, but the most documented incidences are those that happen in marine areas.

Since the 1960’s, oil spills have been recorded as major environmental problems caused by increased deep sea oil production and explorations, and the transportation of crude oil over the seas by use of voluminous tankers, which can hold up to 500,000 metric tons of oil. It is estimated that the annual quantity of oil spills from such tankers exceeds one million metric tons. Together with spills from crankcase lubricants and gasoline solvents by industries and individuals, spillage of oil into the world’s waterways is approximated to be at the rate of 3.5 million to 6 million metric tons annually.

Quid pro Quo

According to Wikipedia,

“An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially marine areas, due to human activity, and is a form of pollution. The term is usually applied to marine oil spills, where oil is released into the ocean or coastal waters, but spills may also occur on land. Oil spills may be due to releases of crude oil from tankers, offshore platforms, drilling rigs and wells, as well as spills of refined petroleum products (such as gasoline, diesel) and their by-products, heavier fuels used by large ships such as bunker fuel, or the spill of any oily refuse or waste oil.”

The Gulf of Mexico is a very big ocean. The amount of volume of oil and dispersant we are putting into it is tiny in relation to the total water volume.
~ Tony Hayward

How Do Oil Spill Happen?

Oil spills take place when there is failure of the oil drilling machinery, due to human error, carelessness, deliberate acts or mistakes, or because of natural disasters or marine accidents especially for refineries or tankers shipping any form of petroleum product. When such acts take place, spillage from the refineries, barrages, tankers, storage facilities and pipelines normally release huge amount of oil into the water body and/or inland areas.

As a result of such an occurrence in the water body, the oil floats on the water and quickly spreads out across the surface of the water which forms a thin layer. The thin layer, also known as an oil slick, gets thinner and thinner as the oil continues to spread over the water surface. Eventually, the oil slick becomes a very thin layer with the appearance of a rainbow, which is also referred to as sheen. In cases where there is spillage of huge amounts of oil, the oil forms a very thick layer on the water surface as it spreads out.

Whenever oils spills happens, the consequences are grave including serious harm to marine mammals and birds and can also harm sea otters, shellfish, and fish. The harms are because the oils interfere with the insulating ability of mammals with furs. The animals may also get trapped in the oil, especially birds and sea otters, exposing them to cruel conditions notwithstanding the possibility of swallowing the oil which can be poisonous. As such, during oil spills, hundreds to thousands of marine mammals, birds, turtles and fish usually end up dying.

Various Causes of Oil Spill

  1. Carelessness or people making mistakes

Carelessness or mistakes or errors made by people is one of the primary causes of oil spills. According to the Office of Response and Restoration with regards to oil spills, the majority of the oil spill cases are associated with human error, carelessness and mistakes that could be avoided. Such cases are normally noted where there are petroleum refineries, barrages, tankers, storage facilities and pipelines.

For instance, all acts of human mistakes and carelessness were linked to the Exxon Valdez Oil Spill in March 1989. On a separate case, the BP’s head of safety party blamed human error for the oil spill in 2010. Further, reports indicated that five key human errors led to the Gulf oil rig blowout, causing one of the biggest oil spills in history.

  1. Breakdown or failure of equipments

Any equipment can breakdown or fail unexpectedly, and when it does, serious outcomes can follow particularly depending on the function of the equipment. In the petroleum industry, breakdown and failure of equipment has led to a number of oil spills and it’s usually the most dreaded. Be it in the drilling rig or refineries, their mechanical breakdown or malfunction have caused unprecedented oil spill catastrophes.

Mechanical failure of the BP’s drilling rig, for example, partly contributed to the Gulf spill – one of the world’s major oil blowouts in history. Top BP officials at the time admitted that enormous mechanical failure prevented the rig from sustaining the mounting pressure from below, which caused the blowout. Oil tankers may also breakdown thus releasing large amounts of oil into the oceanic bodies, though its occurrence is not very common in water bodies. It only accounts for about 2% of all oil spillage in water bodies.

  1. Natural disasters

Almost all the oil spills into the oceans and waterways from machinery transporting petroleum such as pipelines and oil tanker ships are due to natural disasters. Very heavy storms in the oceans, shaking of the sea floor due to earthquakes, and hurricanes have contributed to oil tanker ship accidents or breakage/leakage of underground pipelines thereby causing colossal oil spills.

For instance, the La Coruña oil spill of 1992 in Spain was as a result of unexpected rough weather as the oil tanker ship was entering the port. The ship broke into two releasing about 74,000 metric tons of crude oil into the water. A similar case was experienced the same year when an oil tanker ship was damaged in a heavy storm spilling about 66,700 metric tons of fuel into the water body near Mozambique.

  1. Deliberate acts

Deliberate acts by terrorists, vandals, or countries at war have contributed to a number of oil spillages. Marine habitats and inland water systems have been polluted by oil spills especially by acts of vandalism, sabotage or terror activities with an aim of completely destroying the perceived enemy’s economic wealth base. Most of the criminals target major pipelines. Such incidences are rampant in war and petroleum resource zones.

A prime example is the 2015 Revolutionary Armed Forces of Colombia (FARC) attacks against Columbia’s oil industry which caused a spill of approximately 400,000 gallons of crude oil. Wars such as the Gulf War also resulted in colossal oil spills. The Gulf War oil spill is recorded as one of the leading oil spills in history.

  1. Illegal dumping

Though illegal dumping does not account much for the oil spillages, some people or industries just choose not to follow the right channels for dumping used oil. Instead, they choose to dump or discharge the used oil directly into water bodies. Illegal dumping of used oil in inland areas also contributes to the problem because it causes oil spills which eventually get washed into the water systems by storm water.

  1. Water vehicles and water sports

Water vehicles such as boats and water sports account for other causes of oil spills into surface waters. It happens when petroleum leaks from the water vehicles such as boats and jet skis or during water sports in water bodies such as lakes, rivers and oceans.

Image credit: pixabay


Rinkesh is passionate about clean and green energy. He is running this site since 2009 and writes on various environmental and renewable energy related topics. He lives a green lifestyle and is often looking for ways to improve the environment around him.