Environmental Management in Oil and Gas Exploration and Production, developed by Oil Industry International Exploration and Production Forum (E&P Forum) and UNEP, provide an overview of environmental issues in the oil and gas exploration and production industry, and of the best approaches to achieving high environmental performance in all parts of the world. Management systems and practices, technologies and procedures are described that prevent and minimise impact.
The environmental effects of oil extraction are numerous and important to consider. When different kinds of oil enter the sea, many physical, chemical and biological degradation processes start acting on them. These processes change the properties and behaviour of the oil. Some processes cause the oil to “disappear”, but the fact that it is no longer visible on the water surface does not necessarily mean that it is gone or has been rendered environmentally harmless.
In terms of effects on wildlife, there is no clear relationship between the amount of oil in the marine environment and the likely impact on wildlife. A smaller spill at the wrong time/wrong season and in a sensitive environment may prove much more harmful than a larger spill at another time of the year in another or even the same environment. Even small spills can have very large effects. Thus, one should not merely compare figures — the size of an oil spill is certainly not the only factor of importance in terms of what environmental damage can be caused by the oil.
There are also a myriad of socioeconomic effects. An oil spill can have a number of direct and indirect effects on fisheries, for example. Valuable fishing and shellfish areas may be closed for fishing for shorter or longer periods because of the risks of the catch being tainted by oil. Concentrations of petroleum contaminants in fish and crab tissue, as well as contamination of shellfish, could pose a significant potential for adverse human health effects. Until these products from nearshore fisheries or aquaculture have been cleared by the health authorities, they could be banned from human consumption. Indirectly, the fisheries sector will suffer a heavy loss if consumers are either stopped from using or unwilling to buy fish and shellfish from the region affected by the spill. As concluded by the Third R&D Forum on high-density oil response (2002), “sunken heavy fuel oil may have significant impact on seabed resources and fishing and mariculture activities”.