In Texas, two people were killed and nearly three dozen treated for chemical exposure Thursday following a leak of toxic hydrogen sulfide gas at a Houston-area oil refinery operated by Pemex, the Mexican state-owned petroleum company. Authorities issued a shelter-in-place order for Deer Park and neighboring Pasadena for several hours, telling residents to seal doors and windows and turn off air conditioners. Thursday’s disaster comes less than a month after hundreds of Deer Park families were forced to evacuate their homes after a pipeline explosion sent a massive column of fire and toxic smoke into the sky.