Others opted to stay indoors and `` shut their windows and doors to make sure the acid cloud was not entering their home , '' she said . NEW : Environmental official says area evacuated , no traces of chemical remain . Toxic cloud forms Saturday after chemical spill at Pennsylvania plant . Local residents taken to hospital ; cause of death not known .
NEW : Environmental official says area evacuated , no traces of chemical remain . Toxic cloud forms Saturday after chemical spill at Pennsylvania plant . Local residents taken to hospital ; cause of death not known .