On June 24, 1989 the Uruguayan motor vessel Presidente Rivera ran aground in the Delaware River near Claymont, Delaware. Approximately 307,000 gallons of No. 6 oil were released, contaminating the riverbanks of Pennsylvania, New Jersey, and Delaware for approximately 30 miles.

On June 23, 1989, the Greek tank ship World Prodigy struck Brenton Reef near Narragansett Bay, about 4 miles south of Newport, Rhode Island. The vessel was loaded with 8.2 million gallons (over 195,000 barrels) of No. 2 home heating oil. The grounding tore a 200-foot gash in the hull of the ship and released 290,000 gallons of No. 2 fuel oil into the Rhode Island Sound.

Image credit: Eric Gundlach, Research Planning Inc.

The Oil Pollution Liability and Compensation Act of 1989 was introduced into the Senate by Sen. George J. Mitchell, D-ME on April 4, 1989. It was later incorporated into H.R. 1465 as an amendment to the Oil Pollution Act.

On March 24, 1989, the Exxon Valdez oil tanker spilled almost 11 million gallons of oil into relatively pristine Alaskan waters. It was America's largest oil spill at the time, and is largely credited with inspiring the passage of the Oil Pollution Act.

Image credit: Exxon Valdez Oil Spill Trustee Council.

The Oil Pollution Act of 1990 was introduced into the legislative process for enactment on March 16, 1989. It was sponsored by Rep. Walter B. Jones, D-NC.

BP, the United States, and the five Gulf states agreed to a settlement, or  Consent Decree, resolving claims for federal civil penalties and natural resource damages related to the Deepwater Horizon spill. The $20.8 billion settlement, which included up to $8.8 billion for natural resource damages, was the largest environmental damage settlement in U.S. history.

Final Programmatic Damage Assessment and Restoration Plan and Final Programmatic Environmental Impact Statement released. Record of Decision for the Final Programmatic Damage Assessment and Restoration Plan and Final Programmatic Environmental Impact Statement in March 2016.

Deepwater Horizon trustees release Draft Comprehensive Restoration Plan for the Gulf of Mexico.

In the Clean Water Act Trial, Judge Barbier determined that 4 million barrels of crude oil were released from the reservoir, of which 3.19 million barrels or approximately 134 million gallons were released into the Gulf of Mexico.

Image credit: NASA. 

After four years shoreline assessments are  completed. Up to 18 SCAT teams operating simultaneously conducted ground surveys of over 4,300 miles of shoreline (over 28,000 miles with repeat surveys).

After addressing emergency restoration activities, NOAA and co-trustees negotiated with BP on a $1 billion framework agreement for early restoration.

Notice of Intent to begin restoration scoping and prepare a Programmatic Environmental Impact Statement.

The presidential commission’s final report, “Deep Water: The Gulf Oil Disaster and the Future of Offshore Drilling,” goes public.

BP confirmed that well kill operations on the MC252 well in the Gulf of Mexico are now complete, with both the casing and annulus of the well sealed by cement.

Trustees release a Notice of Intent to Conduct Restoration Planning.

In total, 609 trajectory forecasts were issued during the response. 

BP attempted to stop the flow of oil with a “static kill,” which involved pumping heavy drilling fluid, mud, and cement into the well. The operation was successful, though more work was required to permanently seal the well.

Image credit: BP. 

From July 10 to July 15, BP installed a new “capping stack” (a containment cap) with a tighter seal than the previous containment cap). At 2:25 p.m. (CT) on July 15, BP closes the valves on the cap and stops the oil leaking out of the riser.

From June 1 to June 10, BP begins its third attempt to contain the oil from the leaking well using a Lower Marine Riser Package (LMRP) Cap Containment System; oil continues to leak from the Top Cap and make its way to the surface.

Tests confirmed that tarballs from the Deepwater had washed ashore in all five Gulf states.