At least nine separate explosions were heard, starting at approximately 10:30 a.m. local time. They were said to have ripped a jagged trench that runs almost 2 km. The expanded trench was said to be contiguous with the city sewer system, and the open holes thought to be at least six meters deep and three meters across.



In several locations, much larger craters of fifty meters in diameter were evident with numerous vehicles buried or toppled into them. An eyewitness said that a bus was "swallowed up by the hole".

Damage costs were estimated at 75 million U.S. dollars. The sewer explosion was traced to the installation of a water pipe, by a contractor several years before the explosion, that leaked water on a gasoline line laying underneath. The subsequent corrosion of the gasoline pipeline, in turn, caused leakage of gasoline into the sewers. The Mexican attorney general sought negligent homicide charges against four officials of Pemex, the government-owned oil company. Also cited were three representatives of the regional sewer system and the city's mayor.