The death toll from an ammonia leak in southern Mexico has risen to seven after a pipeline rupture Tuesday that caused an explosion. State-owned oil company Pemex said Wednesday that at least three people are still being treated for injuries sustained in the blast, while 40 others suffered from inhaling ammonia. The government of the southern state of Oaxaca said the leak happened when construction machinery hit a pipeline carrying ammonia to a petrochemical plant. About 1,200 people were evacuated from nearby homes. The explosion is not the first accident to hit Pemex this year; in January, an explosion caused by a gas leak at the company's Mexico City headquarters killed 37 people and injured 126 others.
