"It must be remembered that catastrophes, in spite of the obvious consequences and all the attention they attract, are inferior to other sources of oil pollution in their scales and degree of environmental hazard. Land-based oil-containing discharges and atmospheric deposition of products of incomplete combustion ... these diffuse sources continuously create relatively low but persistent chronic contamination over huge areas. Many aspects of chemical composition and biological impacts of these contaminants remain unknown." (Stanislav Patin, in the book: Environmental Impact of the Offshore Oil and Gas Industry)

"Oil spills can have long-lasting and devastating effects on the ocean environment, but we need to know more about damage caused by petroleum from land-based sources and small watercraft since they represent most of the oil leaked by human activities." - - - "Oil slicks visible from the air and birds painted black by oil get the most public attention, but it is consumers of oil, not the ships that transport it, who are responsible for most of what finds its way into the ocean. For example, oil runoff from cars and trucks is increasing in coastal areas where the population is growing and roads and parking lots are expanding to accommodate it. Rivers polluted by oil in waste water or the improper disposal of petroleum products are a significant source of oil in the sea as well." (Report in 2002 by the National Research Council (NRC) Committee on Oil in the Sea: Inputs, Fates, and Effects)

"... comes from human activities: street runoff, industrial waste, municipal wastewater and wastewater from refineries. - - - Small dribs and drabs add up to a very large amount - - - Obviously, there's a great concentration of cars, there's a greater concentration of the use of petroleum and you have a lot of paved surfaces." (Comment of one member of the Committee)

" ... that a considerable part of oil pollution of the marine environment is caused by oil contaminated waters discharged via storm water systems...". (Baltic Sea Helsinki Commission)

"Dispose of used oil, antifreeze, paints, and other household chemicals properly, not in storm sewers or drains. Clean up spilled brake fluid, oil, grease, and antifreeze. Do not hose them into the street where they can eventually reach local streams and lakes". (U.S. EPA)

"Pollution comes from visible sources such as oil spills, but many little known sources have big impacts, as well. Polluted runoff is the most pervasive of these, carrying oil, litter, fertilizers and other pollutants to the oceans". (The Ocean Conservancy:Polluted Runoff)

It is a fact that the big oil spills account for a considerably smaller total annual input than the constant, diffuse input from land-based sources. These daily, never-ending additions to the oil load on oceans and coastal areas is not dramatic. It does not kill seabirds, fish, shellfish or marine mammals within a few days, it does not cause large-scale destruction of beaches, it cannot be as brutally seen or felt as large oil slicks from ships or offshore oil wells. It is difficult to blame anyone in particular for the continuous"leakage" of oil from streets and rivers, like the large-scale marine "recreational" oil pollution caused by pleasure craft, because the blame falls on each and everyone of us.

Oil discharged with untreated or insufficiently treated municipal sewage and stormwater — urban runoff — comes from cars, machinery, spills at filling stations and garages, flushed-out residues of lubricants, etc. The stormwater contains waterborne and airborne pollutants; everything that is flushed onto or falls down upon the hard surface will become constituents of the contaminated stormwater: car exhausts, particles from worn tyres, small spills of oil from engines of different vehicles, small oil spills from garages, workshops, residues of oils and lubricants that we want to get rid of.

Oil also enters the marine environment with untreated or insufficiently treated waste water or stormwater from various coastal facilities: coastal industries, coastal refineries, coastal oil storage facilities, oil terminals, and reception facilities. Untreated stormwater from ports, refineries, oil storage facilities, oil terminals etc. especially oil terminals, has a high oil content that originates from valves, pumps, loading ramps for vehicles, quays, etc.

People pour untreated waste water and residues directly into rivers and the rivers bring the pollution, including the oil, to the sea.

Consequently, a lot of oil goes literally down the drain from our towns and cities into the sea — either through a municipal sewage treatment plant, where it will harm the treatment process, or more or less untreated. When streets, roofs, handling areas in ports, and other hard surfaces are washed by rain and snow, the resulting waste water (stormwater) is flushed into the general sewer system or into storm drains along roadsides. If the sewage treatment is adequate, the stormwater and municipal sewage will both be treated. If no treatment plant exists, or treatment facilities are inadequate, the sewage, including the stormwater, will be discharged into the sea more or less uncleaned.