What is petroleum? What are oils? What are hydrocarbons?
  • Petroleum means "rock oil", from the Greek petros/Latin petra (rock), and the Greek elaion/Latin oleum (oil). The term petroleum is nowadays used as a common denotation for crude oil (mineral oil) and natural gas, i.e., the hydrocarbons from which various oil and gas products are made. Petroleum, then, is a collective term for hydrocarbons, whether solid, liquid or gaseous.
  • Reserves of natural gas and crude oil have formed over millions of years as plants and animals have been broken down and undergone chemical change at high temperature and pressure. That is why oil and natural gas (and coal) are referred to as "fossil fuels". One finds petroleum in porous rock-forming large sedimentary basins, where the oil and gas has been trapped by some kind of barrier thereby forming a reservoir.
  • When pumped out of a well on land or in the seabed, crude oil is a complex mixture of thousands of different chemical components, mainly organic compounds — hydrocarbons — which usually make up about 95 per cent of the crude oil (however, hydrocarbon contents as low as around 50 per cent also occur). • Before being used as fuel (for energy generation, machinery and vehicles), or as a raw material in the petrochemical industry, crude oil is refined into different fractions. At the refinery, crude oil is separated into light and heavy fractions, which are then converted into various products, such as petrol, diesel oil, jet fuel.

How is oil and gas extracted from the seabed (offshore extraction)?
  • Wells are drilled into the seabed to the depth of the oil reservoir. The crude oil pumped from wells is a mixture of natural gas, water (formation water and/or production water) and hydrocarbons. The gas is separated from the oil and water and further treated and either flared off or used as natural gas for various purposes. Water and solid particles are removed from the oil component of the crude oil.

What are "refined" oil products?
  • Once delivered to a refinery, the crude oil is subjected to distillation and other separation and refinement processes. The resulting products from these processes are a number of fractions with different characteristics and ranges of use:
    • natural gas;
    • raw gasoline (benzine and naphta), the end product of which is petrol (gasoline);
    • intermediate distillates, the end products of which include light gas (fuel) oil, diesel oil, aviation fuels, kerosene, etc.;
    • heavy distillates, giving end products like heavy gas (fuel) oil for cracking processes, as well as lubricants, waxes, etc.;
    • residues, the end products of which are heavy fuel oils, asphalt (bithumen), tar and coke.
  • Refined oil products are, roughly, divided into the four main categories: Fuels. Lubricants. Vaxes. Asphalt (bitumen). Fuels is the largest of these categories, with the largest product volumes and number of products. Oil is also the raw material for industry to manufacture thousands of industrial and consumer products. Crude oil constitutes the raw material for production of plastics (polymers). Furthermore, oil is used for the manufacture of products such as rubber, paints, fertilizers, detergents, dyes, textiles, solvents, medicine, ink, pesticides, varnishes and much more.
  • [READ MORE about characteristics]
  • [READ MORE about use]

Are tanker accidents the major source of marine oil pollution?
  • No. Although every major oil spill from a tanker or a rig, hitting coastal areas and beaches and killing marine life and seabirds, is a tragedy and causes much damage, it has been estimated that oil spills in conjunction with tanker accidents or oil platform blowouts account for a minor part, approximately 10-15 per cent, of the total annual oil input of oils to the marine environment. According to a recent report by the National Research Council of the U.S. National Academy of Sciences, the total input of oils to the marine environment is about 1.3 million tonnes per year. The main categories of sources that contribute to this input are: natural seeps — 46%; discharges from consumption of oils (operational discharges from ships and discharges from land-based sources) — 37%; accidental spills from ships — 12%; offshore extraction of oil — 3%.
  • However, although the total amount of oil entering the ocean from tanker and accidents and blowouts might be lower than what is generally believed, every effort must be made to reduce that figure even more. Unlike natural seeps, which we cannot stop from happening, we can do much to prevent and avoid all kinds of oil spills resulting from human activities, including accidents. This holds true for all operational discharges from ships at sea, and from all discharges of oils from land-based sources. And it holds true for both discharges of "wet" oil products and for hydrocarbons in gaseous form.
  • [READ MORE about sources of oil pollution]
  • [READ MORE about quantities]

Can tankers be made wreck-proof?
  • No. Even with the latest developments in ship's design, with double hulls etc., accidents/collisions and groundings are likely to be occurring also in the future, with more oil spills of varying sizes as the result. But much can be done to improve safety, because it is not merely a matter of technical solutions in terms of design. See below: What can be done to prevent marine oil pollution.

How, then, does oil enter the marine environment in other ways?
  • Sources of oil input to the marine environment are often divided into natural, sea-based and land-based sources.

  • Natural sources of oil in the marine environment are places where crude oil and natural gas seep naturally out of fissures in the ocean seabed and eroding sedimentary rock. These seeps are natural springs where liquid and gaseous hydrocarbons leak out of the ground (like springs that ooze oil and gas instead of water).

  • Land-based sources include discharges of untreated or insufficiently treated municipal sewage and storm water (urban runoff); discharges with rivers; discharges of untreated or insufficiently treated waste water from coastal industries; accidental or operational discharges of oil from coastal refineries, oil storage facilities, oil terminals, and reception facilities; emissions of gaseous hydrocarbons from oil-handling onshore facilities (terminals, refineries, filling stations) and from vehicles exhausts (traffic).

  • Sea-based sources include accidental oil spills from tankers and other commercial vessels, grounded and abandoned vessels, oil platforms (blowouts), and pipelines. Sea-based sources are also deliberate, operational discharges of oil from all kinds of commercial vessels (ship- or cargo-related discharges), oil platforms, and pipelines. Also, emissions of gaseous hydrocarbons from tankers and pleasure craft, and from oil extraction are examples of such sources, as are other kinds of ship-related activities (dry docking, scrapping), and dumping of oily waste, etc.).

What happens to oil spills in sea water?
  • Every oil spill in the marine environment is unique, because every time oil enters the sea a number of factors will decide the physical, chemical and biological degradation of the oil in that particular area. Some of these factors are the composition (what kind of oil) and amount of oil discharged; the quantity and duration of the discharge/spill; the time of year at which it occurs; the temperature of the air and the receiving water body; the weather conditions; the properties of the shore line (rocky, sandy, mud flats, mangroves, etc.); the amount of oil-degrading micro-organisms in the area; and the supply of oxygen in the water. Once the oil is in the sea water, a number of things can happen — these processes are called weathering, spreading, dispersion, evaporation, dissolution, biodegradation, sedimentation, emulsification, dissolution, oxidation, biodegradation, and much more.

Does oil in the sea only kill seabirds?
  • No, oil spills can harm wildlife in a number of ways. However, it should be realized that there is no obvious relationship between the amount of oil spilled in the marine environment and the impact on wildlife. The impact will depend on such factors as the spread of the oil slick, the type of oil spilled, the location of the spill, the timing/season when the spill occurs, the sensitivity of the regional environment (e.g., species composition, proximity to bird breeding colonies, etc.) and the nature, toxicity and persistence of the oil.
  • Sea birds are particularly sensitive to oil. In a cold climate an oil spot the size of 2-3 sq. centimetres can be enough to kill a bird. The insulating effect of the plumage is destroyed by the oil, and the bird freezes to death (hypothermia). If a bird gets smeared with a lot of oil this may clog its feathers and make it impossible for the bird to fly.
  • Similarly, mammals (seals, polar bears, sea otters and others) living in cold water areas can also die of hypothermia as their fur loses its insulating ability once it has been covered in oil. Fur seals and sea otters are examples of such species. Marine mammals like whales and dolphins can be damaged in different ways by oil when they inhale large quantities of oil-contaminated water.
  • Pneumonia, congested lungs, intestinal or lung hemorrhage, liver and kidney damage, are examples of other effects caused when birds or marine mammals inhale or ingest oil.
  • Sea turtles these nest on sandy beaches, which if oiled can lead to a number of problems, e.g., contamination of eggs, newly hatched become oiled on their way over the beach to the water, irritation of mucous membranes (in nose, throat and eyes).
  • Also fish and shellfish can be damaged by oil in the water, as oil products are toxic to larvae.
  • Organisms on the seabed (bottom-living organisms) will also be affected, once the oil through various processes is transported to deeper water layers.
  • As for different habitats, oil damage will vary due to the characteristics of the coastline and its on-land and underwater vegetation: very different things will happen to rocky shores, sandy beaches, mangroves, mud flats, marshes, coral reefs, etc.
  • [READ MORE about wildlife]
  • [READ MORE about habitats]

Can a damaged coastal habitat and damaged wildlife ever recover from an oil spill?
  • Yes they can, but it can be — and often is — a matter of many, many years, even decades. Again, every situation is unique and depending on the particular conditions and circumstances in that area and the characteristics of the spill (see above on the fate of oil in the water). Some areas might recover in a matter of weeks, whereas others will need up to 20 years. The recovery of an ecosystem will also depend on the share of important populations being killed off or affected by acute poisoning.

Can an oil spill affect human health?
  • Yes. Volatile components (the strong smell that you feel from oil products is due to such gases that evaporate) of oil can burn eyes, burn skin, irritate or damage sensitive membranes in the nose, eyes and mouth. Hydrocarbons can trigger pneumonia if it enters the lungs. Benzene and other light hydrocarbon can damage red bloods cells, suppress immune systems, strain the liver, spleen and kidneys. Generally, refined products tend to be more toxic, but people who clean up shorelines from oil spills must protect themselves from inhaling these gases also when it is a matter of crude oil. Some of the light fractions of oil, such as the aromatic components (e.g., benzene), are also known to cause cancer and are very toxic to humans.
  • [READ MORE about human health]

Who pays for the damage caused by oil spills?
  • An oil spill, particularly a large one, can result in serious and long-term economic repercussions on the coastal communities of the affected area, particularly in regions which are heavily depending on coastal and marine resources. Fisheries (including fish farming and shellfish) and tourism are the two sectors that are likely to suffer the most. Also, it is a shock and a cause of great sadness and distress for people who see their shores get destroyed by oil, even if the area can eventually be cleaned. Thus, the concept of "paying" is not just a question of money.
  • When it comes to paying in terms of giving economic compensation for the damage caused by an oil spill from a tanker, there is an internationally agreed system of compensation. But ultimately, the costs will to a great extent be carried by nations, coastal municipalities, and individuals.
  • [READ MORE about global agreements on compensation, conventionsfunds]
  • [READ MORE about economy and human health]

What can be done to prevent marine oil pollution?
  • From land-based sources? Better management of stormwater, better treatment of household sewage and industrial wastewater, more efficient burning in boilers (power plants), more efficient collection of waste oils from petrol stations and households, additional measures to reduce discharges from industrial processes and installations, including refineries and other chemical industries.

  • From sea-based sources? A number of additional measures could be envisaged to further improve the safety and environmental performance of tankers and other vessels, and of offshore oil rigs. Well-trained crews, strict fire safety regulations on board, better navigational equipment, traffic separation schemes in busy shipping corridors, and frequent inspection of ships (particularly older ones), are all measures that could and should be taken to further minimize the risks of collisions/accidents and groundings. Further improvements of ship's design will also help to minimize the size of a spill (and hopefully altogether eliminate the risk of a spill) if an accident occurs. Better facilities in ports for ships to leave their oily liquid waste and solid oily waste are also an important measure to ensure that the wastes are treated in an environmentally acceptable way.

You see big rescue operations at sea and shore cleanup operations, but can they really stop anything?
  • Yes, there are several methods to be used at sea and on land, but no miracles can be performed and an oil spill is always a cause of damage to the environment and the communities that are affected.
  • [READ MORE about combatting at sea]
  • [READ MORE about shoreline cleanup]
  • According to the International Tanker Owners Pollution Federation (ITOPF), "given the difficulties of cleaning up oil at sea, many oil spills result in contamination of shorelines". ITOPF points out that initial clean-up responses to a spill at sea are "often based upon the use of dispersant chemicals or the containment and recovery of oil using booms and skimmers. Whilst these techniques can be of use in the right circumstances, there are many difficulties associated with employing them effectively. The type of oil and concerns over potential impacts of dispersed oil can preclude dispersant use. For example, they are not effective against many commonly transported oils which have a high viscosity, and soon become ineffective against lighter oils because natural weathering processes or the formation of water-in-oil emulsions greatly increases oil viscosity, often very quickly (a few hours to one to two days). The application of dispersants to treat large quantities of spilled oil also requires specialised equipment and extensive logistical support. Containment and recovery is limited by sea conditions and the relatively small oil encounter rate which the available systems can achieve. Together, these factors usually mean that only a small fraction of a major spill can be dealt with at sea, and it is almost inevitable that oil will threaten coastal resources and contaminate shorelines".
  • ITOPF also summarizes that "it is important to start removing oil promptly from contaminated shorelines because as time passes and the oil weathers, it will stick more and more firmly to rocks and sea walls, and may become mixed with or buried in sediments. Reliance is frequently placed on locally-available equipment and manpower, rather than specialised equipment. Good organisation and management are the key to effective clean-up."

Can I myself do anything at all to prevent further marine oil pollution?
  • Yes, there are plenty of things that you as an individual can do — or rather make sure that you don't do. Become oil-wise!
  • As you can see from the list of land-based sources and activities, and also from the sea-based sources when it is a matter of recreational boating, individuals and households can certainly contribute to the important efforts to minimize the input of hydrocarbons/oils to the marine environment.
  • Be very careful with what you do with oil-containing waste from your household. Don't flush it in the sewers or pour it into the storm sewer systems — street gutters and storm water systems still often drain directly to lake, streams, rivers, and wetlands. Clean up spilled oil on the ground and don't hose it into the street, where they can eventually reach local streams and lakes.
  • If you are in charge of a workplace where oil products are handled, either as the main activity or as part of other activities, introduce routines for recovering, storing and disposing of used oils and other residues in a safe and environmentally-friendly way. Out of sight might be out of mind, but the oil you pour into sewers and storm water systems will not disappear, only cause damage somewhere else.
  • Leave used engine oil for recycling. If your community doesn't supply services for recovery and recycling, find other ways of at least storing the used oil in a safe place instead of pouring it into sewers or street gutters.
  • If you have a motor boat (leisure craft) with a two-strike engine, replace that engine with a four-stroke engine! As you can see from the list of sea-based sources of oil to the marine environment, two-strike engines are quite terrible in that respect.
  • Reduce your private consumption of fossil fuels, including oils, by using collective means of transportation whenever possible. If you have a car, be careful with maintenance (older cars do not necessarily have to drib and drab oil on streets, or "burn oil" instead of petrol/gas).
  • Learn more about all the places and activities in everyday life where oil products are handled and used. The more you know about all the possible land-based and sea-based sources of oil, and how easily oil actually enters the marine environment because of ignorance or negligence, the more you can also see ways of avoiding pollution — and guide other people to do the right thing.