The Governor of Coahuila , Humberto Moreira Valdés , told Telling the Televisa television network that the mine 's ventilation service Supply , which uses Using fans to import oxygen and export dangerous gases , was still in operation .

after the murder Killing of two female hostages two-and-a-half days in , spetsnaz operators from federal security service ( fsb ) alpha and vympel , supported Supporting by a russian ministry of internal affairs ( mvd ) unk unit , pumped Self_motion an undisclosed chemical agent into the building 's ventilation system and began Process_start the rescue operation .

Most deaths were attributed Causation to carbon monoxide poisoning Bodily_harm due to power generators or kerosene heaters being used Using indoors without proper ventilation .

With no services running into the adjoining platform to create the piston effect pushing air into the station , ventilation was poor and temperatures in the tunnel rose to over .