Deepwater Horizon Natural Resource Damage Assessment

On April 20, 2010, an explosion of the Deepwater Horizon (DWH) drill rig caused the largest offshore oil spill in U.S. history. The well spewed oil for 87 days and released millions of barrels of oil into the Gulf of Mexico. The Department of the Interior responded quickly to the disaster, saving wildlife, documenting injury, and helping with the cleanup.

The Deepwater Horizon Natural Resource Damage Assessment Trustees conducted a natural resource damage assessment. The goal is to return the natural resources injured by the spill to the condition they would have been in if the spill had not occurred. In accordance with the Oil Pollution Act of 1990, the Trustees assessed injuries to natural resources and the lost use of those resources caused by the DWH oil spill.

During a typical NRDA process, injury assessment is completed before restoration projects are developed and implemented. The Trustees were able to begin restoration earlier in this case because in April 2011, BP agreed to fund up to $1 billion in early restoration projects before the injury assessment was completed.

Injury Assessment

The Deepwater Horizon NRDA injury assessment was the largest ever undertaken; thousands of pieces of data were collected.

The Trustees' injury assessment included hundreds of scientific studies. The Trustees looked at a variety of Gulf habitats, including deep sea sediments, water column, nearshore, and shoreline habitat; and wildlife such as fish, marine mammals, sea turtles, shellfish, corals, and birds. Both private and public lands were adversely affected, including critically important national and state wildlife refuges and parks, and national estuarine reserves. All the data collection efforts were completed in 2016 when the global settlement was reached. 

Interior assessed injuries to our trust resources - sea turtles, birds, and endangered species such as the Gulf sturgeon, beach mouse, brown pelican, the Kemp's ridley sea turtle, and others. Assessing injury involved everything from staff counting the number of oiled birds and sea turtles (alive and dead) to surveying damage to wildlife habitat such as the dunes and beaches that are essential to nesting birds and sea turtles.

Read more information about the natural resources affected by the spill >