Sometimes they do blow up spontaneously. Methane gas is a natural substance that can leak into buildings. It can even be found in fresh water wells. And you are a teacher?<quoted text>
You right they spontaneously blow up.
Sunday Feb. 3, 2013
MEXICO CITY (KABC)-- A gas buildup is believed to be the cause of the explosion in Mexico City last Thursday at the headquarters of the Pemex oil company.
The blast killed 37 people and injured dozens of others. It was the petroleum giant's worst disaster in more than a decade.
Attorney-General Jesus Murillo Karam said an investigation found no evidence of explosives in the blast that collapsed several lower floors of the Petroleos Mexicanos administrative building.
"We've been able to determine that the explosion was caused by an accumulation of gas in the basement of the building," he said. "This explosion, at its peak, generated an effect on the structures of the floors of the building, first pushing them up and then causing them to fall, and that was the primary cause of deaths in the building."
The methane gas was apparently ignited by a spark from an electrical fault. The source of the methane gas has not yet been identified.