This month’s oil spill in California and the sinking of the X-Press Pearl off the coast of Sri Lanka in July have renewed attention to the environmental dangers of such disasters, especially the toll they take on marine and coral life. In this question and answer segment, the United Nations Environment Programme (UNEP) explores the dire impact of oil spills, the cost of clean-ups and what can be done to limit damage to the environment and ecosystems.

How do oil spills happen?

There are many types of oil spills and most are minor, for example when oil spills from a ship when it is being refuelled. But serious incidents, like the 2020 oil spill in Mauritius, bring consequences that can be felt for decades. Most of the major oil spills happen when a pipeline breaks, a tanker sinks or runs aground or when a drilling operation goes wrong.

Are some oil spills worse than others?

Yes, not all oil spills are the same. Aside from the size of the spill, the type of oil or refined oil product will impact the severity of the spill. For example, gasoline is worse than crude oil as it is lighter and more toxic. In the Sri Lankan spill, the environmental issue was compounded as the ship was also carrying nurdles, small plastic pellets, that take thousands of years to degrade, as well as over 80 containers of various hazardous chemicals. The nurdles flooded beaches and turned up in the stomachs of fish, causing further environmental damage. The risk of bunker oil leaking remains and will only be put to rest once the shipwreck is removed from the sea.

How can we prepare for future oil spills?

Governments and the oil industry must have preparedness plans in place and understand what to do when an oil spill happens. Equally important is conducting regular spill response training exercises. The quicker and better prepared the reaction the less the environmental impact. Oil spill response can be tiered so that small spills are handled at a local level, larger spills are handled on a national level and major spills call on an international response. The Sri Lanka case also demonstrates the growing risks of growing global container shipping, and the need to prepare for complex incidents involving oil, hazardous chemical spills and other products.

How do you clean up an oil spill?

It all depends on the time it takes for the clean-up crew to get to the site of the spill, the weather conditions, type of oil, shoreline type and environmental sensitivity amongst other factors. If a crew can reach a spill in a few hours, they can aim to contain and skim the oil. Containment and skimming is done by mechanical means such as using booms and skimmers. Booms are floating physical barriers, that stop the oil spreading, and skimmers, modified boats, skim the oil off the top of the water.

Once the oil reaches the shoreline or spreads out it becomes harder to clean up. When oil gets close to the shoreline, manual clean-up campaigns are typically deployed, while trying to get wildlife away from the impacted area using floating dummies and balloons as a deterrent.

However, no solution completely removes the oil, in the best case scenario, only 40 per cent of oil from a spill can be cleaned up by mechanical means. The ability of natural recovery to restore the environment can play an important role, and actions to enhance its effectiveness needs to be considered.

How do oil spills harm ocean and animal life?

If an oil spill happens in an area with wildlife the damage can be significant. Oil destroys the insulating ability of fur on mammals and impacts the water repelling qualities of a bird’s feathers, without the insulation or water repelling qualities mammals and birds can die from hypothermia. Dolphins and whales can inhale oil, which has an impact on their immune system and can impact reproduction. While fish and shellfish aren’t immediately impacted, because oil floats on water, as the oil mixes and sinks, fish can experience impacted growth, enlarged livers, fin erosion and a reduction in reproductive capabilities. In fish and shellfish, the impact can also be lethal, when it is not lethal, they are often no longer safe for human consumption.  

How important is restoration after an oil spill?

Restoring an area impacted by an oil spill is crucial to recovery. Before restoration can begin an understanding of the damage done by the spill needs to be undertaken, this is done through continued ecological, biological and chemical studies and analysis.

Once the damage is understood steps can be taken to accelerate the recovery, particularly those enhancing natural processes.  Restoration can include the reintroduction of species affected by the spill, erosion control, if damage from the spill has sped up erosion, and a change in management practices, such as controlling fishing and hunting, in impacted areas.

Do oil spills have a financial impact?

Answer: In short, yes. Not only does the clean-up have to be paid for, and in the cases of big spills this can run into billions of dollars, but the long-term impact of a spill also has an economic consequence. If, for example, like in Sri Lanka, the spill is in an area of outstanding natural beauty tourist numbers often decline, if the area is reliant on fishing, this often must be halted while the area recovers. Legal action to obtain compensation for economic and environmental damage is often a long and burdensome affair, especially for countries with limited experience and lacking the legislative framework to deal with such incidents.

For further information, contact Hassan Partow, Hassan.partow@un.org; Mark Radka, Mark.radka@un.org