There is usually a contingency plan already in place for a region or body of water. This includes an action plan, list of contacts, probable oil movement patterns, and technical data such as "sensitivity maps" which outline areas that are ecologically sensitive and therefore most in need of protection. When an oil spill occurs, the potential impacts of the spill are evaluated, and workers try to control it as quickly as possible.
Different types of equipment are used to track the movement of the oil, such as low-flying planes or helicopters, infrared and ultraviolet cameras, computerized tracking and dispersion simulation models, tracking buoys which drift with the oil and transmit their location by radio & satellite, radar, microwave and laser-induced fluorescence.
To prevent the oil from spreading, floating booms (mechanical barriers placed in the water to stop the flow of the oil) or sorbent booms and barriers (porous material used to absorb an oil slick) are used.
Once the oil spill has been contained, there are a number of methods used to recover the oil from the surface of the water.
- Skimmers are used to mechanically remove the oil without creating major biological or chemical changes to the water.
- Sweep systems, a combination skimmer and boom, are attached to a ship or boat. As the vessel moves forward, this system contains and collects the spilled oil, which is then pumped into storage tanks.
- Sorbents are materials that soak up the oil. These can be natural like peat moss or sawdust, or synthetic like polypropylene or polyester foam. Once the absorbent material has been applied to the oil, the mixture is recovered with the aid of nets, rakes, forks or pike poles.
- Manual recovery is another common method especially for areas with a high concentration of oil. Buckets and shovels are used to remove the oil.
Once the oil has been recovered, it is separated from the water, often by using settling tanks, and disposed of through re-refinery, burning, or other methods.
Clean-up and restoration
For the clean-up and restoration of shorelines from oil spills, many people trained for the job usually pitch in with simple hand tools (e.g. rakes, shovels, wheelbarrows, garbage bags, high and low-pressure hoses and absorbent material) to clean up. This process must be done carefully in order to avoid unnecessary erosion and damage of the shoreline.
Generally, three methods can be used to clean oil off the shoreline:
- chemical and hydraulic dispersion: chemical clean-up agents or high-pressure water hoses are used to wash oil from coarse sediments, rock surfaces and artificial structures; low-pressure water flushing removes oil from fine sediments, shores with vegetation and marshes;
- steam cleaning: steam is used to clean artificial structures and rock faces;
- removal: using graders and scrapers for large quantities of oil on the shoreline.
Skilled emergency crews work quickly to rescue any wildlife that have been affected by an oil spill. Even a relatively small oil spill can have a dramatic impact on bird and animal populations. Therefore, even though this requires a lot of time and effort, is costly, and has a low success rate, it is an important part of the process
Sometimes, it is deemed best not to respond to an oil spill in certain areas, for one of three reasons: the oil spill occurred in a sensitive environment; natural processes would be faster and more effective than human efforts; and high-energy wave energy may break the oil up more effectively.
The following Environment Canada Web sites contain further information on oil spills, clean-up procedures and equipment:
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