In the main industry tries to mitigate against accidents This can be small comfort when accidents do occur. Oil spreads rapidly once spilled. The longer the time, the more equipment needed. After four days a large spill can cover 40-50 square kilometres. Mechanical controlling equipment for oil spills is limited to a 200,000 litres estimated capability.
Larger spills require chemical intervention, which has serious environmental effects.
Highly viscous oil forms a 'mouse' in rough seas, making the volume to be recovered larger and more difficult. Most existing equipment cannot operate with waves greater than 2 metres, winds greater than 20 knots and currents greater than 1 knot. With strong current and large spills the impacts can extend for many miles. Technology does not currently exist to prevent offshore weather driven oil slicks reaching the shores. Current industry practice is to allow offshore slicks to disperse without clean up effort.