Thousands of incidents occur each year in which oil or chemicals are released into the coastal environment. Spills into our coastal waters, whether accidental or intentional, can harm people, the environment, and the economy. To help, the Office of Response and Restoration has developed more than 3,300 Environmental Sensitivity Index (ESI) maps. These maps cover the majority of the U.S. coastline and include information on shoreline shape and biological and socioeconomic resources.  The maps are used to rank sensitivity to oil impact, but can also be used in evaluating coastal-erosion potential and coastal-storm vulnerability and in monitoring coastal change.