At 12:04 am on the morning of March 24, 1989, the Exxon Valdez oil tanker ran aground on Bligh Reef in Prince William Sound, creating the largest-ever oil spill in US waters and the most extensive and expensive spill cleanup in history.
The Exxon Valdez was a single-hulled oil tanker, built in 1986. It was 300 metres long, 50 metres wide, with a capacity of 235 million litres of oil, manned by a crew of 21 and capable of making 16 knots. On March 23 at 9:12 pm it left Valdez Terminal in Northern Alaska with 200 million litres of Prudhoe Bay crude, bound for Washington State. A pilot steered it out through Valdez Narrows and returned control to the ship captain, Joseph Hazelwood. The presence of icebergs forced the Valdez out of shipping lanes. The captain turned control over to the third Mate and an Able Seaman, both tired and inadequately rested from a previous shift. The Captain went to his quarters. The on-duty crew failed to make a planned return to the shipping lanes, and the ship ran into Bligh Reef at 12:04 am on March 24.
The impact ruptured 8 of 11 tanks on board, spilling over 40 million litres of oil into Prince William Sound in 6 hours. The oil slick would eventually spread over 470 miles, affecting 1100 miles of coastline, helped by a storm on March 26. The spill killed an estimated 250,000 to 500,000 birds, 1000 sea otters, 12 river otters, 300 harbour seals, 250 bald eagles, 22 orcas, and billions of salmon and herring eggs.
Cleanup began almost immediately. A helicopter spread dispersant by air, with limited success. A containment boom was erected around the vessel within 35 hours. A controlled burn of some escaped oil reduced its volume by 95% and made cleanup easy. However, the March 26 storm spread and frothed the oil slick, making dispersant and burning impossible. Much of the oil ended up high on shore because of spring tides, and had to be steam-cleaned off by hot water jets.
The cleanup and recovery cost Exxon Mobil an estimated $2 billion, with much of that recouped through insurance. It involved over 11,000 personnel, 1400 boats, and 85 aircraft, and continued for 2 years. Monitoring continues to this day. The NOAA states that, as of 2007, more than 98,000 litres of oil remain in coastline sand, dispersing at a rate of 4% per year.
The Exxon Valdez eventually underwent $30 million in repairs, and was recommissioned as the Seariver Meditteranean, working for a subsidiary of Exxon Mobil. It remains in service in 2009.