Cancer Alley is the regional nickname given to an 85-mile (137 km) stretch of land along the Mississippi River between Baton Rouge and New Orleans, in the River Parishes of Louisiana, which contains over 200 petrochemical plants and refineries. This area accounts for 25% of the petrochemical production in the United States. Environmentalists consider the region a sacrifice zone where rates of cancer caused by air pollution exceed the federal government's own limits of acceptable risk.