Mexico City – Three miners died from gas poisoning over the weekend in the northern Mexican state of Durango, state prosecutors said.
The accident happened on Saturday afternoon at the Santa Rita de Otaez mine, where the three miners - a supervisor, a driller and an assistant - were exposed to ammonium nitrate gas.
Two of the men, a father and son, went into a section of the mine that had been abandoned many years ago and where gas had apparently accumulated, the Durango state Attorney General's Office said.
The supervisor went looking for them after they failed to return within 10 minutes and was also overcome by the fumes.
Inhaling ammonium nitrate gas causes death within about two minutes, miners said.
An explosion killed 14 miners last month at the Sabinas artisanal coal mine in northern Mexico.
Sabinas is located in Coahuila state, where the worst mining disaster in Mexico's recent history occurred - an explosion on Feb. 19, 2006, at the Pasta de Conchos coal mine that killed 65 men.
The National Human Rights Commission, Mexico's equivalent of an ombudsman's office, said in May that it documented incidents in which public servants failed to ensure compliance with safety and hygiene standards inside mines.