It was either a gun powder explosion or a munitions dump that exploded. If any Spanish speaking anons can figure out the intent of the tweet below,
"Precaución! Explosión de polvorín en Chimalhuacán Estado de México, se aproximan servicios de emergencia."
https://twitter.com/Rescate_Condor/status/1110657143018004481
and some more photos,
https://twitter.com/GobChimalhuacan/status/1110671339923357697