The incident involving the Amoco Cadiz occurred when the supertanker, registered in Liberia and owned by the American company Amoco, encountered severe weather conditions while navigating the busy shipping lanes off the coast of Brittany, France. Despite attempts to manage the situation and anchor the ship safely, it ultimately ran aground on the Portsall Rocks, approximately three miles from shore. The impact was devastating; the vessel split in two, resulting in a massive breach of its hull. This catastrophic failure led to the release of around 220,000 tons of crude oil into the Atlantic Ocean, making it the largest oil spill recorded at that time.

In the days and weeks that followed, the oil spread across a vast area, severely affecting the coastal ecosystem. The spill contaminated beaches, harmed marine life, and disrupted local fishing and tourism industries. The ecological consequences were dire, leading to the deaths of countless seabirds and marine animals, along with long-lasting damage to the coastal environment. The French government launched an extensive clean-up and recovery operation involving numerous agencies, volunteers, and environmental groups to address the spill's impact, but the effects lingered for years.

The disaster also spurred significant public outcry and raised awareness regarding the necessity for stricter regulations on oil transportation and environmental protection measures. International discussions on maritime safety protocols intensified, leading to an eventual reevaluation of safety practices in shipping and the prevention of similar incidents in the future.