Despite the relatively small amount of oil released, several factors contributed to the spill's severity: timing, location, abundance of wildlife and substandard cleanup efforts. In comparison, one of the largest oil spills in history, the rupture of an oil well in the Gulf of Mexico that released 140 million gallons (3.3 million barrels) of oil, caused relatively little damage because it happened in the open sea where currents and winds contained it until it disintegrated.