Residents didn’t know their neighborhood was built near an abandoned oil well spreading toxic fumes

SAN ANTONIO — In Texas, suburbs have sprung up where oil pump jacks once bobbed.

At the Preserve at Medina, a subdivision of brick-and-siding starter homes in southwest San Antonio, students filed off a school bus on a hot afternoon. One child turned down Vesper Branch, a street with a plugged oil well ringed by a heavy black metal fence:

“CAUTION flammable gas,” a sign on the fence warned…