The first readings Abigail Edgar took of hydrogen sulfide and methane at oilfields in Caldwell County in 2021 were so high that she thought her equipment was malfunctioning.
“It was off the scales. Methane was off the scales and hydrogen sulfide was off the scales,” said Edgar, a master’s student in geography at Texas State University. “The monitor would immediately start beeping when I crossed the property line.”
Edgar was recording dangerous levels of hydrogen sulfide at wells on private property in Caldwell County, 30 miles southeast of Austin. Hydrogen sulfide is a toxic and highly flammable gas often found in oil and gas formations. During the course of her research, the gas was so potent at three separate wells that Edgar’s respirator did not provide enough protection and she had to leave for her safety.
Edgar teamed up with University of Cincinnati environmental scientist Amy Townsend-Small, an expert on methane, to take another round of measurements in 2023. They found the wells were directly releasing gas — including hydrogen sulfide and methane — into the atmosphere in a process called venting. Some of the wells venting gas were alongside public roads. Others were next to backyards and driveways.
In a paper published in Environmental Research Com