Hydrogen sulfide hotspots, regulatory failure

By Will Evans, The Examination, and Caroline Ghisolfi, Houston Chronicle

We knew we had a story when Sam Birdwell answered our call and began talking openly. 

Birdwell had retired after a long career with the state of Texas, patrolling oil fields to make sure companies followed the rules concerning hydrogen sulfide (H2S), a toxic gas that comes up with oil drilling and can kill you in high concentrations. 

There’s no mistaking Sam Birdwell for an environmental activist. He’s proud of his Texas roots cowboying on ranches and roughnecking in the oil patch. Pumping fossil fuels out of the ground is just fine by him, as long as it’s done right. 

But Birdwell said there was something that still kept him up at night: the elderly residents and young children who were exposed to the gas — not enough to kill, but enough to make them sick. He’d seen too many oil facilities leaking H2S in residential neighborhoods, near schools and families. And he didn’t have the tools to make it stop. 

That conversation, and reporting from freelance journalist Tom Brown, set us on a path to learn how residents of oil-field communities are affected by this gas and what oil companies and regulators are doing — and not doing — about it. 

Along the way we realized that, in Texas, there’s nothing that shows the public where potentially dangerous hydrogen sulfide hotspots are located. We, at The Examination, teamed up with the Houston Chronicle’s Caroline Ghisolfi, Amanda Drane and Amelia Winger and mapped for the first time the oil and gas wells associated with high levels of H2S. We found that tens of thousands of people live nearby, facing risk of exposure. Some suffer headaches, nausea and other health effects, yet when Texas inspectors find the gas venting into the air, companies seldom face penalties. 

Finding people 

Our first challenge was to find the people affected by this invisible gas. The Texas agency that regulates air quality has a database of complaints, but doesn’t categorize which ones are related to H2S and does not include complainants’ names or addresses. We went through hundreds of them, flagging which ones were likely H2S leaks and filing records requests for the investigation files. We cross-referenced geographic clues in the complaints with another agency’s GIS of oil field facilities to pinpoint the problem location. Then we used Google Maps to locate nearby addresses and cold-called residents living nearby. 

That’s how we found Vanessa Hinojos. She and her family live in Odessa, Texas, across the street from an oil facility that has been leaking hydrogen sulfide for years — causing headaches, nausea and a lot of worrying about long-term health effects for their three kids. 

Identifying patterns

Reviewing so many files also revealed patterns. Inspectors kept coming back to the same problem spots, but the companies never seemed to face significant penalties and the leaks just continued. In one instance, inspectors found such high levels outside of the Hinojos house that they felt sick and fled. And still the problem wasn’t fixed. 

We created timelines in Google Sheets to keep track of all the complaints and investigations, and that helped bolster our finding that regulation was weak, and turned into a slimmed-down timeline that we published on the Hinojos case. 

Proving exposure 

Residents complained that the gas often affected them, but it’s invisible and floats on the wind, making it hard to document and easy to dismiss. We spoke to researchers who study air pollution, industry consultants and former state officials to devise a way to measure ambient H2S levels. We landed on two methods. 

One of them didn’t work out. Scientists had devised a way to detect H2S by exposing photo paper to the air (but not light) and seeing if exposure to the gas discolored the paper. We worked with one of the researchers, placing tubes of photo paper in several locations and sending them in to be developed. In the end, researchers said the samples confirmed the presence of H2S but it was hard to determine the exact level, so we left that out of the story. 

After consulting with experts, we also bought a portable data-logging H2S monitor — the kind that professionals use in the oil field — and placed it in the yard of the Hinojos family. The monitor logged ambient H2S levels every 15 seconds. We analyzed about two months of data and found that the levels of H2S were over the state limit on more than half of the days — at one point 90 times higher than the state limit. 

Showing scope 

We knew from our reporting that the Hinojos family was not alone — far from it. Yet no government agency clearly mapped out the full scope of exposure. While the Railroad Commission of Texas (it regulates oil, not trains) collects data on H2S levels and maps out oil wells, it doesn’t put those two datasets together. We parsed, cleaned and vetted millions of well records maintained by the Commission to correctly identify the location, activity status and historical H2S recordings associated with each oil and gas site. We mapped, for the first time, more than 54,000 wells associated with high enough concentrations of the gas to be potentially lethal on direct exposure. 

Then we estimated the number of residents living in the immediate vicinity of those wells and the number of schoolchildren who spent hours every day breathing that air. We leveraged a population gridding algorithm developed by the National Aeronautics and Space Administration, which draws from national censuses and population registers, to measure population density in the half-mile radius surrounding each well. We used Texas Education Agency data to tally the number of schoolhouses in those radiuses and their student populations. 

The numbers went straight into our findings and the map gave residents a tool to determine their proximity to this dangerous gas. 

In the end, it turned out Sam Birdwell was right — oil facilities were leaking H2S near families and schools, residents were getting sick and complaining, and regulators had failed to stop it.

Read the team’s reporting, and learn more about the 2024 Philip Meyer Award winners.