When the Dust Settles

Eva Hershaw’s story, which recounts how the frequent dust storms blowing through Texas feedlots might be spreading antibiotic resistance, won NASW’s Science in Society Award in 2016. Hershaw is a freelance journalist based in Italy. 

The curtain of dust that swept over the Panhandle on October 17, 2011, descended from the northwest. It was a chinook wind, a cold front that slid off the eastern slope of the Rockies, pulling milky clay particles from the flatlands of New Mexico as it raced across the state line. It had been the driest year that Texas had ever known, and the soil that lay on the harvested cotton fields was bare for the taking. As it passed Amarillo, the storm cloud engulfed entire herds of cattle.


These awards honor and encourage outstanding investigative reporting about the sciences and their impact on society. This story was honored in the Science Reporting for a local audience category in 2017.

At 4:15 p.m., as the air grew dark and thick, the anemometer in Friona clocked the wind at 71 miles per hour. The Dimmitt police filed a report with the same time stamp: “Powerlines trees barn roof blown down.” Five minutes later, an update: “Duststorm with visibilities below 0.25 mile.” At 5:05 p.m., power lines went down in Plainview. Twenty minutes later, the roof of a gas station blew off in Levelland.

From the National Wind Institute, at the converted Reese Air Force Base, just outside Lubbock, radar tracked the progression of the now full-blown haboob, a collapsed thunderstorm riding the edge of the advancing cold front. As it cartwheeled toward Texas Tech University, it grew to more than a mile and a half in height, a moving wall of turbulent dust. Residents stopped at streetlights and leaned onto their dashboards, watching as it consumed what little blue sky remained.

The next morning, residents on the outskirts of Lubbock took little notice of the thin film that dusted their roofs and encased their window frames. The storm that wreaked havoc on the Caprock that October afternoon was fierce, but it was not uncommon. The Panhandle endures an average of three to four major dust events every year, and sits amid a stretch of rangeland that records the highest annual sustained wind activity of any non-mountainous region in the nation.

People in the area have grown accustomed to such devastation. But recent research suggests that those winds might carry a threat that no one had imagined. The Southern Great Plains are home to nearly 80 percent of the cattle that live on U.S. feedlots, sprawling bovine cities that hold an estimated 8.2 million cattle. Those animals don’t get to do much. They stand around and eat and sleep and try to shake flies from their hide. They also defecate, a lot. If it rains, some of the tons of waste created every year by those cattle will run into nearby holding ponds. But most of the feces are caked to the ground, desiccated by the sun, and bulldozed into piles that will fertilize nearby hay fields. Throughout this process, specks of those feces are swept up by the wind.

In addition to a steady diet of flaked corn and sorghum silage, cattle are regularly administered steroids, some portion of which is excreted in their feces. Eight years ago, a Texas Tech professor, Philip Smith, funded by a U.S. Department of Agriculture grant and with the cooperation of local feeders, tried to figure out if those steroid remnants went airborne, and what happened to them if they did.

Smith eventually determined that steroids were indeed blowing off of feedlots and settling into the local environment, where they could act as endocrine disrupters among nearby aquatic species. All in all, it was a good bit of science, the sort of thing that not only meets professional standards but might make a difference outside of the academy.

In 2010, as he was working on the study, Smith had lunch one afternoon with a colleague, Greg Mayer. As Smith discussed his work, Mayer started asking him about another substance that is found in cattle feces: antibiotics, which are regularly given to cattle. Were the antibiotics traveling in the air? And if so, what sorts of effects might they have? Smith was intrigued by these questions, and he soon asked Mayer to join him in conducting a follow-up study.

As a pair, the two men seem as well matched as a classic comedy duo. Smith, an early-life asthmatic and environmental toxicologist who has been at Tech for fifteen years, was born and raised in Kentucky. Mayer, who grew up in southern Illinois, just across the Ohio River from Smith, is a molecular biologist who arrived at Tech in 2008. Smith is jovial and speaks in a casual, off-the-cuff manner that undoubtedly endears him to students. He’s a microscope guy, well versed in the impact of environmental contaminants on local species. Mayer is an expert in DNA testing and the more measured of the two. In meetings, Smith has a habit of glancing at Mayer after making an extemporaneous statement and asking his friend for a reality check. “Am I wrong, Greg?” he’ll say. Often, Mayer will pause, nod, and offer a subtle correction. Likewise, when Mayer, talking with a journalist, wades deep into the details of their sampling methodology, Smith will gently steer him back to conversational English.

Between August and December 2012, the two men—this time without any help from feed yards or the USDA—carried out a new round of sampling. In the bed of a truck that they parked on county roads adjacent to ten Lubbock-area feed yards, they set up small, generator-powered vacuums. On a number of windy days, they collected upwind and downwind air samples. The results confirmed their suspicions: downwind, they found antibiotics—specifically tetracycline—present at significantly higher levels than in the upwind samples. Yet as they dug deeper, they discovered something even more worrisome. Along with the antibiotics, they found another hitchhiker: remnants of bacteria that had acquired a gene that made them resistant to tetracycline.

“The tetracycline resistance was 400,000 percent more prevalent downwind than upwind,” said Smith. At some of the locations, there was tetracycline resistance in 100 percent of the samples. “That was really the wow moment,” said Mayer.

When Smith and Mayer published their findings in the April 2015 issue of the journal Environmental Health Perspectives, public health experts and scientists called for action. “If I were living downwind of these facilities, this would be high on my list of concerns,” said Lance Price, an epidemiologist at George Washington University who studies antibiotic resistance. Bob Martin, the director of the Food System Policy Program at Johns Hopkins University, said that it was unexpected to see such research come from a university known for its ties to the industry. “It is very alarming,” he said. “I am afraid this might be a wildfire situation.”

But Smith and Mayer’s work also drew very different responses from others, placing the scientists and their school at the intersection of two forces that, in the Panhandle, reign supreme: the wind and the cattle industry.

A feedlot in the Texas panhandle. Photo courtesy of Wikimedia Commons.

There were approximately 68 million cattle in the United States in 1940. Today, the number stands at around 92 million. This growth has been attributed to increasing levels of efficiency, symbolized by the rise of the modern American feed yard, where cattle are confined during the final months of their lives and fattened up for slaughter. In the 150 to 220 days it spends on the feed yard, the average steer will gain between 600 and 800 pounds. In 1964 the average weight of an American cow at slaughter was 1,020 pounds. In 2015 the average weight was 1,364 pounds.

The Panhandle, with its vast tracts of sparsely populated land and proximity to abundant sources of grain, has been an ideal setting for the expansion of the feeding industry. The largest feedlot operator in the Panhandle—in fact, the largest private feedlot operator in the world—is Amarillo-based Cactus Feeders, which processes around 1 million cattle annually on ten feed yards. One of those lots, outside Tulia, holds an estimated 45,000 cattle. On a typical workday there last November, as I sat in the office of Cactus chief operating officer Paul Defoor, the sky was gray and the cattle turned in their pens, heads down. Defoor, tall and thin, wore an impeccably white cowboy hat and spoke passionately about the benefits of agricultural progress in a free society.

“This company’s history speaks to an era of this country when people were willing to take risks and had a vision for a food-production system that could sustain millions, not just themselves,” he said. “And that is what we are all enjoying today. Modern societies rely on modern agriculture. It’s the only way that your lifestyle can exist the way it exists today.”

In practice, modern agriculture relies heavily on antibiotics, which enhance the absorption of nutrients, treat and prevent disease, and counterbalance the negative effects of cattle’s grain-dependent diet (cattle evolved to eat grass, not grain). Currently, there are no state or federal reporting requirements for antibiotic use in agriculture, despite estimates that it accounts for nearly 80 percent of the nation’s use of antibiotics. “It comes down to a risk assessment that we have relied on our institutions to provide,” Defoor said. “And the FDA says that’s an acceptable, tiny, small risk given the value of the product that we are providing to mankind.”

The problem with such massive deployment of antibiotics is that the more they’re used, the less they work. Between 2000 and 2010, global consumption of antibiotics jumped 36 percent. Most of that jump, according to the Center for Disease Dynamics, Economics & Policy, a public health research organization in Washington, D.C., was caused by increased access to antibiotics in emerging economies like Brazil, Russia, India, China, and South Africa. The second significant driver is the growing international demand for animal protein.

An expansive body of scientific research has tied antibiotic use in animal food production to increased antibiotic resistance among bacterial populations. In recent years, scientists have been able to document that these resistant bacteria are capable of being transferred to humans. Last year, a team from the Center for Emerging Infectious Diseases, at the University of Iowa, found that farmers in Iowa who were exposed to livestock were more likely than other local farmers to have been colonized by antibiotic-resistant bacteria.

The World Health Organization has called antibiotic resistance the “single greatest challenge in infectious disease.” In 2013 an estimated 23,000 Americans—and 700,000 people worldwide—died from bacteria that no longer respond to antibiotics. But it’s tough for the powers that be to grapple with the problem. Last year, President Barack Obama’s senior science adviser, John Holdren, spoke to a commission tasked with fighting antibiotic resistance. Asked what he expected to be the biggest obstacle facing the commission, he said, “Folks who have been doing well under the status quo are generally reluctant to change it.”

In January 2015, eight days after Smith and Mayer’s findings were first publicized, in a university press release and by the Environmental Health Perspectives website, Ross Wilson, the president and CEO of the Texas Cattle Feeders Association, sat in the office of Duane Nellis, the president of Texas Tech. Wilson, who also serves as a lobbyist for the TCFA, had called the meeting to discuss what he regarded as “sensational comments” made by Smith and Mayer. Next to Wilson sat his longtime acquaintance Robert Duncan. From 1992 to 2014 Duncan served in the Texas House and Senate, and throughout his years in office Wilson and the TCFA had made modest contributions to his election campaigns. In 2014 Duncan was appointed chancellor of the Texas Tech University System.

Wilson, who describes the meeting as routine, explained to Duncan that the researchers’ preliminary findings—that antibiotic-resistant genes were spreading on the wind—had caused him a bit of a headache. This was a big accusation, he said, given that it was based on a “superficial, initial set of science.” What’s more, Wilson suggested that Texas Tech had engaged in a possible breach of protocol. It was his understanding, he said, that university press releases and statements by researchers would be thoroughly reviewed before publication, and he believed that this had not been done. According to Wilson, by the end of the meeting Nellis and Duncan said that they would review the case, to see if the proper procedures had been followed. (There is no evidence that a formal review occurred. Duncan says that Nellis was supposed to follow up on the matter informally but doesn’t know if he ever did. Nellis has chosen not to comment.)

A few months after the meeting, Wilson clarified his objections to Smith and Mayer’s work. “They found genetic material. That does not mean that there’s any organism that is out there that is going to transfer that potential resistance,” he said. “And if people expect us to sit idly by and not defend our members when some are alleging this is our fault, it’s not happening.”

Wilson was quick to note that if repeated studies by other scientists were able to establish that feed yards in Texas were generating live, antibiotic-resistant bacteria that were moving on the wind, the industry would take that very seriously. But, he says, “We still don’t know if we have a problem.”

A boomerang-shaped plume of dust sweeps across northern Texas on February 24, 2007. Photo courtesy of NASA.

One recent morning, Wes Burgett, a manager at the National Wind Institute, pulled up a radar loop from some years back. He wanted to illustrate the concept of single point source pollution, in which a specific place is a source of environmental contamination. In the Panhandle, these places are generally bare cotton fields and cattle pens, which can send large amounts of dust into the atmosphere. In a loop from December 2012, a red storm cloud moved across a black map with white lines demarcating the counties.

The fact that the storm appeared to be red indicated the high levels of dust in the air. As it passed into Bailey County, a speck of white appeared amid the red and then ballooned into a cloud of purple and then magenta, nested within the red storm cloud. Burgett paused the radar. “You see the individual plumes that are different colors here?” he asked. “This is where all the cattle are.” Similar streaks appeared across the Panhandle, single-source tributaries throwing bursts of dust into the air as the storm passed overhead.

Studies have estimated that every day the average cow generates about 28.5 grams of PM10 particles—fecal matter dried in the sun, aerosolized, and suspended in the air. PM10 particles, which are 10 micrometers in diameter or less, are of concern to the EPA because of their ability to pass through the nose and into the lungs. Of even greater concern are the smaller PM2.5 particles, which can remain suspended by the wind for much longer and pass deeper into the lungs. Many of the particulates that Smith and Mayer studied were smaller still.

Researchers have shown that bacterial communities, traveling in the upper atmosphere, have remained alive over long distances. In a bizarre event that illustrated the ability of pathogens to move on the wind, an aggressive fungus not normally found in humans rode a tornado in Missouri in 2011, infecting the wounds of a number of residents injured in the storm and eventually contributing to the death of five of them. In the same wounds, doctors found antibiotic-resistant bacteria that, scientists surmised, could have been picked up as the storm passed over livestock yards.

The case, while not a smoking gun, offers clues about what could happen if antibiotic-resistant bacteria travel on the wind. “There are a lot of things that remain unanswered,” said Mayer. “What is the consequence of the bacteria’s gene sequence when it lands? Can it cause an infection in humans?”

No one knows for sure, but established science does point us in a certain direction. Bacteria are highly promiscuous organisms that readily share and absorb DNA—even, implausible as it may sound, in the afterlife. If airborne bacteria are alive, they will act as ambassadors once they’re deposited onto the ground. Through direct contact, antibiotic-resistant bacteria can inject susceptible bacteria with a copy of its DNA in a process known as conjugation. These copies, known as plasmids, are loose pieces of DNA that float inside the bacteria, carrying its genetic backbone. Once the plasmid has entered the new cell, it will again copy itself and move on to more bacteria; the process can be repeated a million times over. In conjugation, the rate of transfer can be one in one hundred. That is, of every one hundred cells that contact one another, one bacteria will transfer its plasmid to another. “It sounds like the odds of that happening are very low,” says Jim Herrick, a molecular biologist at James Madison University, in Virginia. “But you have to put that up against the fact that there are literally, in a gram of soil, over a billion bacteria.”

If the bacteria are dead, though, then what Smith and Mayer found was naked DNA, which is released by bacteria after their cell walls have decomposed. When these pieces of DNA fall out of the wind, they can be picked up by bacteria on the ground, in a process known as transformation. If live bacteria downwind of the feed yard absorbed the DNA found in Smith and Mayer’s samples, they could acquire antibiotic resistance, though the process is much less efficient than conjugation.

Smith and Mayer don’t know if the bacteria they detected downwind of the feedlots were dead or alive. Nor do they know at what concentrations the bacteria might be found as they move farther away from the feedlots. But they had demonstrated that antibiotic resistance could be spread on the wind.

Four months after Wilson’s meeting with Duncan and Nellis, he got in touch with Texas Tech again. Smith and Mayer’s study had appeared in Environmental Health Perspectives and been noticed by the press, and Wilson’s in-box had been flooded with links to stories with apocalyptic headlines like “Mutant Antibiotic-Resistant Superbugs Are Spreading in Texas Winds” and “Superbugs Go Airborne, Triggering Fears of Global Epidemic.” He was also unhappy about an interview with Smith and Mayer that I conducted for the Texas Tribune, in which Smith claimed that his study was the first to indicate that “we could be breathing these things.” In that same interview, Mayer said that the study’s results had made him “not want to breathe.” Both comments, Wilson thought, were inflammatory. This time, rather than work through the administration, he went straight to the scientists.

It was raining the day Wilson drove to meet Smith and Mayer. He had two intentions. First, he wanted to discuss comments they had made to the media. Second, he wanted them to turn over their raw data—not just a summary of their findings, which is what peer reviewers usually work from, but the numbers they had drawn from their samplers in the field, data that are usually shared with another organization only if the research is carried out jointly, which was not the case here.

For Smith and Mayer, the request struck a nerve. Not only did it seem to disregard the legitimacy of the peer-reviewed journal that had published their work, it also, to their minds, revealed the entitled status that the TCFA enjoyed at a public research institution. “By saying they want to see the data, they create a cloud of suspicion,” Smith said. He and Mayer refused the request, because they feared that the TCFA would use the raw data to shoot holes in their work. “They have money,” said Smith, “and they’ll hire people to say, ‘Well, that peak should have been here.’ ”

Wilson denies any such intention. “I didn’t see it as being an unusual request,” he said, sitting in his office at TCFA’s headquarters in Amarillo this past February. To ensure the accuracy of the findings, he said, TCFA scientists should be able to review the raw data Smith and Mayer used to draw their conclusions. “I would like to see a little more openness on the part of these two gentlemen if we are going to be able to work with them,” he added. “But that remains to be seen.” (In April, at the request of the TCFA, three scientists released a two-page, non-peer-reviewed white paper that took issue with some of Smith and Mayer’s conclusions. The TCFA has now begun its own sampling effort, in an attempt to replicate Smith and Mayer’s study.)

In addition to asking the scientists to turn over their data sets, Smith and Mayer say, Wilson, in so many words, asked them to refrain from speaking to the media. “I told him no in no uncertain terms,” said Smith. “We would not not talk about our research.” They felt that they were being intimidated. “Especially when they sit us down at a table at our office and almost demand that we never say another word about anything,” said Mayer. It’s a claim that Wilson flatly disputes. According to him, that part of the conversation went a bit differently: “I would never ask them not to speak to the media. That’s their prerogative,” he said. “I asked them not to be so damn sensational.”

Asked why both scientists would have come away with that impression, Wilson sat forward: “Let me be candid with you: if the direction they would like to go with this article is that we, in any way, are trying to suppress information, then that is just another spin.”

Smith said that he and Mayer gave Wilson their word that they wouldn’t do anything to draw attention to their research but that they were unwilling to promise more. “We don’t say, ‘Hey, come here, we’ve got this data set, we’ve got this paper, we want you to come write a paper about it,’ ” said Smith. “But beyond that, I said if someone wants to know about our work, I am going to tell them, because in some respect, the public has a right to know.”

The incident upset Smith and Mayer, who have both grown weary of the controversy their research has sparked. “This is like nothing I have ever experienced in science before. And it’s not that we haven’t done cooler things, better things, more technical things,” said Mayer. “It’s just that there isn’t a big industry that cares about it.”

Smith put it another way. “They would like nothing more than for us to zip our mouths, put our instruments away, and never do another study,” he said. “You ask Ross—that would make him a happy man.” He sighed. “I just don’t like to be bullied. I don’t like to knuckle under to people.”

Then, about four months later, the controversy took another turn when Nellis implied that Smith and Mayer were, perhaps, not the only ones who had come under pressure. Nellis was in Laramie last December interviewing for the presidency of the University of Wyoming, when a member of the faculty asked him to clarify his position on academic freedom. Nellis said that he saw great value in industry-university collaboration. But, of course, he said, he considered academic freedom to be fundamental for scientific inquiry.

Without mentioning names, he offered an example, detailing the research done by Smith and Mayer. “The cattle industry is not very happy about that,” Nellis said. He noted that the university had supported the scientists’ work, despite the fuss. “The industry people want me to just go in and fire those faculty,” he added, with a chuckle. “But that’s just not the reality.”

As is usually the case with major public hires, the University of Wyoming put a video recording of the interview online. Someone alerted Smith to the video, and he sent me the link. Hours later, it was placed behind a password-protected firewall. A day after I made a media request, I was granted access to the recording, and during my February meeting with Wilson I played the audio portion of the interview for him and his communications officer, Jayce Winters. Neither of them had heard it before. When Nellis mentioned the cattle industry’s trying to get Smith and Mayer fired, Wilson spoke over the recording without raising his head. 

“That was never discussed,” he said, calmly. Once the tape was paused, he said it again, more slowly: “That was never discussed.”

He was shocked that Nellis would say such a thing. It was blatantly untrue, he insisted. A week later, Wilson sent me an email reiterating his objection. “If you are able to talk with Dr. Nellis, you can tell him I stated he has a horrible memory,” he wrote. “I stated several times in my meeting that we support academic freedom, as it is critically important to the scientific process. How can one support academic freedom and ask that researchers be fired? Dr. Nellis’ comment is absurd.”

After several interview requests, Texas Tech’s office of communications eventually delivered a brief statement from Nellis, explaining that his comments in Wyoming were not meant to be taken literally. “In higher education, the results of faculty research often spark discussion and, on occasion, disagreement,” he wrote, and declined further comment.

By that point, Nellis was no longer Texas Tech’s president. In January, Nellis—who had made other comments during his Wyoming interview that seemed to be critical of Duncan—announced his resignation and went back to teaching. When I spoke to Wilson in February he said he was surprised to learn of Nellis’s move. Despite the misstep in Laramie, he thought Nellis had been doing a good job.

Today, Smith and Mayer are relieved to report that their phones are no longer ringing. They have no interest in confronting the industry and no illusions about transforming it.

“I’m Irish, so you tell me not to do something and I want to jump in with both feet,” Smith said. “But in the end, I am not out to change the cattle industry.” Mayer, too, was eager to put this chapter behind him. When one of our conversations stretched toward the two-hour mark, he made a move for the door. “I have to go feed mice,” he said. “Call me back when you want to talk about the gut microbiome’s reaction to Stevia.”

But they aren’t staying away from the subject that has caused them so much trouble. This past Fourth of July, Smith spent the day at home, drafting a proposal for additional research into wind-borne pharmaceuticals. In their next paper, due out later this year, Smith said that they would answer the question of whether the antibiotic-resistant bacteria blowing off the feed yards are dead or alive. He was careful not to advance any details about their findings but suggested that people stay tuned.

In the end, he said, this wasn’t about proving any person or any interest group right. “In my mind, this is simply an honest pursuit of knowledge.”

This article was reported with support from the UC Berkeley-11th Hour Food and Farming Journalism Fellowship.

 You may read this story in its original format on Texas Monthly.