The Karnes County Sheriff's Office responded to a report of an exploded oil pump, Tuesday afternoon.
It happened off FM 792 and County Road 343, between the towns of Kenedy and Helena.
According to Karnes County Sheriff Dwayne Villanueva, the pump exploded at an oil field facility. The pump was shut off but hydrogen sulfide gas, or H2S, still managed to escape, according to the sheriff. The company in charge of the oil field, Encana, called it "a well control situation."
According to the Occupational Safety and Health Administration, hydrogen sulfide is a "colorless, flammable, extremely hazardous gas with a 'rotten egg' smell." Industrial activities that can produce the gas include petroleum and natural gas.
Neighbors in the area were immediately evacuated and no injuries were reported. Encana said they were working to shut the well down and determine the exact cause.