Natural gas suspected in Mexico oil company blast

Christmas in August

An employee culls through debris searching for office documents amid the rubble left from an office building explosion, in Mexico City, Saturday, Feb. 2, 2013. A Thursday blast collapsed the lower floors of the Mexican state-owned oil company Petroleos Mexicanos, or Pemex, headquarters, crushing at least 33 people beneath tons of rubble and injuring 121. A Pemex spokesman said the floors hit by the explosion housed administrative offices. (AP Photo/Marco Ugarte)MEXICO CITY (AP) — A water-heating system may have leaked natural gas into a tunnel beneath the headquarters of Mexico's national oil company for more than seven months before it was accidentally detonated by a maintenance crew's improvised lighting system, officials said Tuesday, adding fresh detail to the narrative of the petroleum giant's worst disaster in a decade.

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