The location of the chemical plant which exploded is near South Main (which is Highway 90) near the intersection of Fondren. Highway 90 goes to Stafford TX and Missouri City, and Sugarland TX. This is in the southwest part of Houston, outside the 610 Loop.
The major petrochemical industry area is many miles to the northeast -- along the Houston Ship Channel, which runs between Galena Park and Pasadena and lies to the north of Deer Park on the right side of the map.
Until the company was identified, I feared it might be the Texas Instruments plant in Stafford...