Ocean Matters

World Oil Pollution:
Causes, Prevention and Clean-up


Oil Pollution

Just thinking about oil pollution in the oceans conjures up images of massive tanker spills, oiled seabirds and shorelines covered with gooey black oil. This page will examine the causes of marine oil pollution and methods for pollution prevention and spill cleanup.

Types of Marine Oil Pollution 

Oil spills are actually just a small percent of the total world oil pollution problem. According to one study there are about 706 million gallons of oil pollution in a given year. That is a massive amount of oil! The following chart shows different types of oil pollution.

Types of
Oil Pollution

Offshore Drilling
Large Oil Spills
Natural Seeps
Up in Smoke
Routine Maintenance
Down the Drain
Total World Oil Pollution

Millions of Gallons


Percent of
World Total

2.12 %
5.24 %
8.78 %
13.03 %
19.4 %
51.42 %
100 %

The definitions of the different forms of oil pollution are as follows:

“Offshore drilling” pollution comes from operation discharges and drilling accidents occurring during oceanic oil exploration.

“Large oil spills” typically result from oil tanker accidents such as collisions and groundings.

“Natural seeps” come from seepages off the ocean floor and eroding sedimentary rocks.  This type of natural oil pollution has occurred for thousands if not millions of years.

“Up in Smoke” is pollution caused by oil consumption in automobiles and industry. Typically, oil hydrocarbons find their way into the ocean through atmospheric fallout.

Oil pollution from “routine maintenance” occurs from ship bilge cleaning and so forth.

Finally, “down the drain” oil pollution occurs from people dumping oils and oil products down storm drains, etc. Many consider this to be the worst kind of oil pollution. The following images illustrate past oil spills.


A freighter is shown after running aground. Notice the oil leaking out into the ocean.






The oil tanker Mega-Borg released 5.1 million gallons of oil as a result of an oil transfer accident.






Oil tanker Amoco Cadiz. This tanker ran aground off the coast of France in 1978 spilling 68.7 million gallons of oil. Large spills such as this are rare events.





Blowout of exploratory well Ixtox 1 in 1979. When workers were able to stop this blowout in 1980 an estimated 140 million gallons of oil had spilled into the ocean. This is the second largest spill ever, smaller only than the deliberate oil spills that ended the Kuwait-Iraq war of 1991.

Preventing Marine Oil Pollution

There are many different ways we can stop marine oil pollution. In the case of oil exploration and oil tankers, new procedures and equipment have helped reduce oil spills. Most oil tankers are now double hulled to reduce the chance of oil leakage if a tanker runs aground. Ocean-going ships filter out most of the oil from bilge maintenance to ensure that it does not reach the ocean and recycling facilities exist to ensure people do not pour oil down storm drains and pollute millions of gallons of water. Another method is for people to spray-paint fish pictures near storm-drains so people do not put oils and other substances down the drain. This method is cheap and remarkably effective as people find other ways to properly dispose of oils. Even with these new methods, oil pollution still does occur.

Dangers of Oil Pollution to the Marine Environment 

So why is oil so dangerous for the marine environment? Oil exposure damages animal fur and feathers so they cannot stay warm and many of these oiled animals will die by freezing to death. Other problems include accidental poisoning by ingesting oil, blindness from oil exposure, liver damage and other disabilities. If there is a large oil spill, humans have to clean up the excess pollution to ensure that fewer animals will die.


Animals that come into contact with oiled beaches, such as those pictured above, will likely be poisoned, get oil on their fur or feathers and die from freezing or perhaps suffer permanent disabilities. Beach clean-ups minimize the chance of animals either dying or becoming disabled.

Cleanup of Marine Oil Pollution

There are many different types of equipment and methods to assist us in cleaning up oil pollution. Biological oil agents help break down oil so it degrades faster, causing less damage to the environment. Oil booms and sorbents assist in containment and absorption of spilled oil. Skimmers skim surface oils while gelling agents react with oil to form solids that can be cleaned up by suction equipment. Dispersants break oil into droplets where they will do less harm to other organisms. Elbow grease is another method that is used to clean oil spills. This technique involves people physically cleaning the shores with high pressure water hoses, cleaning oiled animals and so forth. Physically cleaning oil on shores is time consuming and very expensive and it can also damage the shoreline further by killing and disturbing any animals still alive after the spill. The following pictures illustrate various methods used to clean up oil spills.


In the first picture we see an aircraft applying a chemical dispersant to the oil spill to make it degrade faster. In the second picture two boats are towing a boom which collects the oil. A skimmer at the back of the boom removes the oil from the ocean.


In the first picture we see a boom protecting a salmon farm. If the oil gets into the pen areas of the salmon farm the salmon will die. In the second picture workers are using hot water from high pressure hoses to clean the oil off the shore. Sometimes this method kills animals but in this case there was no alternative as these beaches were home to animals such as sea otters, sea-birds and so forth.

All images belong to the NOAA's Office of Response and Restoration, and National Ocean Service and are used with permission.

For more information go to:

United Nations Environment Programme

International Tanker Owners Pollution Federation Limited

Transport Canada - Oil Spill Response Plan

World Wildlife Fund

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