If, in the immediate aftermath of Homo sapiens petrolerus, the tanks and towers of the Texas petrochemical patch all detonated together in one spectacular roar, after the oily smoke cleared, there would remain melted roads, twisted pipe, crumpled sheathing, and crumbled concrete.
White hot incandescence would have jump-started the corrosion of scrap metals in the salt air, and the polymer chains in hydrocarbon residues would likewise have cracked into smaller, more digestible lengths, hastening biodegradation.
Despite the expelled toxins, the soils would also be enriched with burnt carbon, and after a year of rains switchgrass would be growing. A few hardy wildflowers would appear. Gradually, life would resume.