1989 : EXXON VALDEZ, etats-unis

- Quantité déversée : 38 500 tonnes

- Durée des opérations : > 1 an

On 24 March 1989, the American oil tanker the Exxon Valdez, which had just loaded 180,000 tonnes of crude oil at Valdez oil terminal, moved away from the shipping lane to avoid meeting with drifting ice blocks. The captain ordered the helm holder to switch to automatic pilot. Less than 30 minutes later, the ship ran aground at speed of 12 knots on Bligh Reef, situated some 10 m deep in Prince William Strait, an important fishing area.

The grounding damaged 11 of the 18 tanks and caused 38,500 tonnes of crude oil to be spilled. More than 7,000 km2 of oil slicks polluted 800 km of coasts (2,000 km including all the small islands and inlets).

This spill of 38,500 tonnes of crude oil made the Exxon Valdez the vessel responsible for the largest oil spill that the US had ever experienced.

This spill was a huge shock for the United States and the Exxon company, who had never imagined such a disaster possible.

During 1989, 11,000 people were employed by Exxon to clean up the damage as quickly and efficiently as possible. Tens of thousands of volunteers and unprecedented means were made available (1,400 ships, 85 helicopters and 1,100 people) to save sea birds and mammals and to clean the shore one beach after another.

In 1990, 1,100 people continued clean-up operations. This workforce was costly; Exxon paid each worker 1,000 dollars per week.

Bioremediation, the acceleration or promotion of natural breakdown processes by micro-organisms, was used. The reduction in the amount of oil covering the surfaces treated was three times more quickly. This technique is therefore recommended for clean-up. Source CEDRE