Ixtoc I was an exploratory oil well in the Gulf of Mexico, about 600 miles south of Texas. On June 3, 1979, the well suffered a blowout and became the largest unintentional oil spill in history.

The firm Petroleos Mexicanos, known as PeMex, was drilling a 2 mile deep oil well, when the drilling rig lost drilling mud circulation. In modern rotary drilling, mud is circulated down the drill pipe and back up the casing to the surface. The goal is to equalize the pressure through the shaft and to monitor the returning mud for gas. Without the circulating mud, the drill ran into high pressure gas which blew out the oil (known as a blowout). The oil caught fire and the platform collapsed.

In the next few months, experts were brought in to contain and cap the oil well. Approximately 10 thousand to 30 thousand barrels per day were discharged into the gulf until it was finally capped March 23, 1980. Prevailing currents carried the oil towards the Texas coastline. The US government had two months to prepare booms to protect major inlets. Mexico declined the US requests for cleanup compensation.

External links

• Ixtoc I history detail - incidentnews.gov - an NOAA site, April 14, 2005