Oiling our Ocean
Over the past 11 years tankers have spilled 370,000 tonnes of oil into the world's oceans.
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Large spills
The graph above shows the number of recorded annual tanker spills seven tonnes and greater.
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Oil spills
It is not a question of if a spill will happen, but when and how big. In 1990 a federal government report on tanker safety in Canadian waters determined that 100 small, 10 moderate and one major spill would occur every year. Environment Canada predicted that a catastrophic spill was predicted once every 15 years.This forecast was based on the level of tanker traffic that was occurring in 1990.The likelihood of an accident escalates with every additional vessel and every increase in the amount of oil transported.
There are few access roads to the North Central Coast. Clean up crews and equipment responding to a spill would have to be flown or shipped into the area.
In spite of technological advances, a clean up is judged successful by industry if only 15 percent of the oil is recovered.
Ballast water
Besides spills, oil tankers plying coastal waters present other, less obvious threats in the form of ballast and bilge water discharges.Ships carry ballast water to maintain stability. The ballast is routinely discharged into the ocean. International shipping traffic increases the risk of bringing invasive alien species into B.C.’s coastal waters. The European green crab was introduced to the San Francisco Bay through ballast water and is currently migrating up the west coast, threatening native crab populations. The introduction of zebra mussels in the Great Lakes cost Canada $70-$120 million between 1989 and 1995 to control the invasion and to help deal with the damage it caused infrastructures.
Canadian regulations call for oil in bilge water to be removed but it remains a source of pollution. Discharge of bilge water has caused increased mortality in marine birds and may cause production of beach tar. On the east coast of Canada, it has been estimated that over 300,000 seabirds are killed annually from the oil released in bilge water. Scientists are concerned that a similar occurrence is already happening on Canada’s west coast but that the currents are washing the oiled seabirds out to sea rather than onto shore.
