Ixtoc I was an exploratory oil well being drilled by the semi-submersible drilling rig Sedco 135-F in the Bay of Campeche of the Gulf of Mexico, about 100 km (62 mi) northwest of Ciudad del Carmen, Campeche in waters 50 m (160 ft) deep. On 3 June 1979, the well suffered a blowout resulting in one of the largest oil spills in history.[3]