On June 3, 1979, a major oil spill occurred. Pemex, a Mexican oil company, was drilling in a deep oil well using one of their rigs, Sedco 135. While drilling, mud began to circulate within the well and slowly fill the well column. As it began to fill with mud, the pressure became too much causing Sedco 135 to blow. This oil spill lasted months resulting in hundreds of thousands of barrels of oil spilled into the Gulf of Mexico. They implemented a variety of reactive measures to contain it such as putting steel, iron and lead balls into the well to slow the spill, drilling relief wells, placing barriers and skimmers nears bays and lagoons, and spraying chemical dispersants. This process lasted approximately 10 months costing Pemex close to $100 million.

This major oil spill was about 30 years prior to Deepwater Horizon. Why do these major oil spills happen? What can they do to prevent them? How can we learn from them?

(Resource: https://en.wikipedia.org/wiki/Ixtoc_I_oil_spill)