Shortly after 11:00 a.m. on Wednesday, July 31, 2019, an explosion ripped through a processing unit at the Baytown Olefins Plant, an ExxonMobil oil refinery. The Olefins Plant explosion resulted in a large fire in the unit, the blaze contained by firefighters but still burning on Thursday. A large and growing smoke plume arose from the explosion site, drifted across the city of Baytown. The smoke plume potentially contains harmful toxins because the Baytown refinery processes light hydrocarbons, including propylene…