This day in history: November 19, 1984 – The Mexico City PEMEX disaster.

Petróleos Mexicanos, or PEMEX, is Mexico’s nationalized petroleum company. On November 19, 1984, the PEMEX LPG (liquefied petroleum gas) facility at San Juan Ixhuatepec, Mexico City was being filled from a local refinery when a pipe ruptured, releasing petroleum gas into the environment for several minutes. The control station noticed the drop in pressure but was unable to immediately identify the cause; as the operators worked to locate the source, the gas cloud (estimated at 60,000 cubic meters) drifted into a flare stack and ignited, exploding and starting numerous ground fires. Workers tried to flee the area and someone finally thought to initiate an emergency shutdown, but it was too late – the LPG storage tanks began to explode (registering on seismographs at the University of Mexico), some raining liquefied gas on nearby structures which then burst into flame. The terminal was totally destroyed, and more than 500 people lost their lives.

Sources: Fire and Blast Information Group, UK Health and Safety Executive