A large blaze at an ExxonMobil refinery located in Baytown resulted in a large plum of potentially hazardous smoke spreading over the neighborhoods surrounding the plant mid-morning on Wednesday, July 31. The smoke is expanding in its reach and has the prospect of not only spreading across Baytown but also into the city of Houston itself. The fire erupted in a unit at the refinery that contains polypropylene, a chemical that can present health risks to people exposed to it….