Inferno at Guadalajara

April 1992, Guadalajara, Mexico. On the 19th, residents start complaining of a strong gasoline-like smell coming from the sewers. Three days later, on the 22nd, numerous gas explosions in the sewers over a time span of four hours destroy kilometers of housing estate and killing 206 people. But who, if anyone, is to blame? What caused the inferno in Guadalajara?