Utah’s Great Salt Lake may turn into a toxic dust bomb. Can a dried-up California lake help stop it?

A sign warns of harsh conditions at Owens Lake near Lone Pine, California, on Feb. 28. The dry lakebed used to be the single biggest source of dust pollution in the United States.

Climate change and ever-thirstier people are helping to dry up the iconic Great Salt Lake. The long-gone Owens Lake offers a cautionary tale — and a way forward.

LONE PINE, Calif. — Peering at the data displayed by one of 13 air-quality monitoring stations scattered across the dried-out expanse that was once Owens Lake, Phillip Kiddoo was impressed. “I’d guess that’s the cleanest air in the country right now.”

The level of PM10 — particulate matter no wider than a fifth or so of a human hair, which can make breathing difficult and worsen heart and lung problems — averaged 4.6 micrograms per cubic meter of air over the previous 24 hours.

Outside the station on a chilly late February day, the wind was blowing, but not too strongly. The sky was blue, with some clouds hanging out over the snowy Sierra Nevada to the west. And the maybe-best air quality in the country could be found at a dried-up lake that not so long ago was the United States’ single biggest source of PM10 pollution.

To put that 4.6 microgram reading into perspective, anything under 40 is “good,” according to the Environmental Protection Agency; above 80 gets into “poor” territory, and above 300 reaches “extremely poor.” Kiddoo, the air pollution control officer for the Great Basin Unified Air Pollution Control District (GBUAPCD), said 20 to 30 years ago, there were days when PM10 would reach 20,000 micrograms per cubic meter. What would that do to a person breathing it in?

“Instant death,” he said. “You’d suffocate.”

In many ways, Owens Lake — which dried up early last century when the city of Los Angeles began diverting the lake’s water supply to a major aqueduct — is a cautionary tale and a harbinger of disasters to come. Climate change is altering patterns of drought and rainfall across the world, and demand for water is growing. Just 500 miles from Owens Lake, Utah’s Great Salt Lake is drying rapidly and creating another stream of toxic dust. And while Owens Lake has finally managed to get its air pollution problems in check, it came at enormous cost. In a sense, it is lucky that there is such an example already out there, if only to demonstrate how important it will be to avoid a similar fate.

The death of Owens Lake began in 1913, when Los Angeles built the L.A. Aqueduct to capture the flows of the Owens River and other nearby surface water and route it south toward the city. By 1926, the lake was dry. Once the lake bed was exposed, windy days would dislodge tiny dust particles and send plumes of them skyward, capable of severely harming any people unlucky enough to be within a 50-mile radius, at least.

This continued, unabated, until the late 1980s, when the EPA officially cited the region as being in violation of federal air quality standards and the area’s pollution control district was given authority to force the city of Los Angeles to fix the problem. A few decades later, the dust-control measures implemented by the L.A. Department of Water and Power beginning around 2000 and overseen by Kiddoo and his team — a combination of ideas that at root are about having something on top of the dust to prevent wind from blowing it up — are working.

“It really is a success,” Kiddoo said. “Nobody was doing it. Nobody knew how to do it.”

Now, Owens Lake is starting to export that success. Delegations from places around the world with drying lakes have come to learn the tricks of the trade, from the Salton Sea in California all the way to Lake Urmia in Iran. Most urgently, the Great Salt Lake and its vibrant, crucial ecosystem sits at the precipice of a new dusty disaster.

A ticking time bomb

The Great Salt Lake has always been shallow, with a depth of just 35 feet before the current crisis began. Since the late 1980s, water levels in the lake, a remnant of the massive prehistoric Lake Bonneville, have dropped almost 20 feet. The Great Salt Lake has lost more than half its total volume and more than half its total surface area. In 2022, its surface level dropped to a record low of about 4,190 feet above sea level.

It is still much, much bigger than Owens Lake — so as it dries and turns into a source of dangerous dust, a far greater number of people would be at risk. About 40,000 people live in immediate range of the blowing dust from Owens Lake, but the Great Salt Lake has 2.5 million on its doorstep — and it is one of the most rapidly growing population centers in the country.

“You could take Owens Lake and put it literally in Farmington Bay, which is just one lobe of the Great Salt Lake,” said Kevin Perry, a professor and chair of the department of atmospheric sciences at the University of Utah, sitting in his office in Salt Lake City. Owens Lake covers about 110 square miles of area in total. Just the dried-up parts of the Great Salt Lake already exceed 800 square miles.

Growing demand for water upstream is the biggest factor behind the Great Salt Lake’s disappearing water. Climate change is also playing a role: Between 8 and 11 percent of the water loss is due to increased evaporation from warmer temperatures, and another 15 to 23 percent can be traced to the ongoing megadrought in the western U.S., which itself has a major climate component.

These factors are combining to accelerate the Great Salt Lake’s dust problem. “My estimation is that the number of dust hot spots have increased by 40 percent in the last four years,” Perry said. Even without the dust, Salt Lake City already has some of the worst air issues in the country. In the winter, cold air can trap pollution in the valley, blanketing the city in bad air; the summer brings wildfire smoke growing ever worse thanks to climate change and ground-level ozone problems that are also a human health hazard. In a quirk of bad luck, the biggest dust seasons are spring and fall, completing a particularly dark bingo card for the region.

Perry finished a study of the dust emanating from the shrinking lake in 2018, only to see water levels drop another 5 feet since then. But the total exposed lake bed isn’t the whole story: Only about 9 percent of the currently dry area is acting as a dust source because of a hard protective mineral crust that covers much of it. The longer that crust is exposed to the elements, though, the more it will wear away.

“We essentially have a ticking time bomb that is just waiting to be set off,” Perry said. “And we don’t know if that’s five years, or 10 years, or longer.”

A dried harbor at Antelope Island in the Great Salt Lake in Utah, on March 2. — A dried harbor at Antelope Island in the Great Salt Lake in Utah on March 2.

Plants, gravel, water

I met up with Kiddoo in the parking lot of the Museum of Western Film History in Lone Pine, whose postcard views of the Sierras to the west and the Inyo range to the east have drawn hundreds of movie productions, from “Tremors” to “Django Unchained.” We hopped in his SUV and, accompanied by enthusiastic pollution control dog Bella, drove out onto what was once Owens Lake.

In the late 1990s and early 2000s, after a period of legal wrangling and study, the L.A. Department of Water and Power finally began helping mitigate the problem it had caused. In the decades since, officials have tried a number of pollution control measures with varying degrees of success. Standing atop the monitoring station, Kiddoo and I could see one of the more effective measures in action: gravel.

Gravel in this case means smallish rocks, about the size of a child’s fist, big enough that you definitely wouldn’t want to be hit with any. The rocks were spread out across a few square miles in various parts of the lake bed to a depth of 4 inches, or 2 inches when a sort of black fabric is laid down beneath the gravel. It is remarkably good at keeping the dust down, but at significant cost — at least $25 million per square mile, even when the rocks are locally sourced.

Phillip Kiddoo, the pollution control officer for the region that includes Owens Lake in California, atop an air quality monitoring station at the lake on February 28. — Phillip Kiddoo, the pollution control officer for the region that includes Owens Lake in California, stands atop an air quality monitoring station at the lake on Feb. 28.

In general, Kiddoo said of the dust-control program, “it’s not cheap.” Owens Lake’s 13 monitoring stations, for example, cost $180,000 each. Over the life of the project, the price tag has exceeded $2.5 billion, an amount that starts to seem all but impossible when you multiply the areas involved at Owens Lake out to something the Great Salt Lake’s size.

We drove on from the gravel, past other control measures: managed vegetation, where hardy native plants manage to hold their surroundings in place; reddish brine pools, where high salinity helps prevent evaporation; and tillage, a method Kiddoo said made him nervous since it used the dusty lake bed itself as a control measure, tilled into mounds and clods and mixed with a few inches of water. Some methods failed quickly and were abandoned; they planted trees at one point, only to find that the windblown dust sheared their bark clean off.

The most obvious, simple and effective method is known as shallow flooding — basically, adding enough water to put a lake back where a lake used to be. We stopped briefly at the aqueduct off to the lake’s west side, the original sin of the country’s biggest dust source, to look at a contraption that essentially created a diversion of a diversion.

From that point, a 60-inch pipe takes water from the aqueduct back out toward the lake; the pipe runs all the way across and around Owens Lake, for 26 miles, eventually shrinking down to a diameter of 18 inches. Numerous smaller outlets shoot off from the main line, sending about 55,000 to 60,000 acre-feet of water per year out to various parts of the lake. (An acre-foot is a unit of water that can cover 1 acre of land to a depth of 1 foot — about 326,000 gallons, or what a family of four might use in a year.) Kiddoo thinks they can get that down to 45,000 acre-feet eventually, allowing more water to head south again to Los Angeles.

The Inyo mountains reflected in the water at a part of Owens Lake where managed vegetation is used to control dust pollution, on February 28. — The water at a part of Owens Lake where managed vegetation is used to control dust pollution reflects the Inyo mountains on Feb. 28.

All these methods combined have brought Owens Lake’s dust problem largely under control. Twenty years ago, the area had around 45 days a year of “nonattainment,” where the 150 microgram-per-cubic meter threshold set by the EPA for PM10 was exceeded. Overall, Kiddoo said, the region had the worst air quality in the country for 25 years.

There are still a few days a year where the air crosses that EPA limit, but the total dust kicked up is down substantially. Early this century, a big year could mean as much as 86,000 tons of dust produced from Owens Lake. Now, that’s down to around 5,000 to 7,000 tons, though 2022 was a bad year at 10,000 tons.

“We aren’t at the finish line yet,” Kiddoo said.

Dusty questions remain

If Owens Lake is at least nearing that finish, the Great Salt Lake is more or less standing at the starting line. The lake is drying, but it is not fully dry. Too much water is being diverted on its way down the mountains and rivers, but water conservation efforts have significant potential to fix that. Officials have yet to implement any dust-control measures, and discussions about their use have only really just begun. And crucially, while Owens Lake has among the most monitored and studied air in the entire country, huge knowledge gaps remain about the dust issues in Salt Lake City — even something as basic as how many times per year the dust storms kick up.

“We don’t know the answer because we don’t have the monitoring put in the right places,” Perry told me, ballparking an estimate of between 15 and 30 per year. The really severe storms, where visibility in town drops to less than a mile, now pop up a couple of times each year. Often, the prevailing winds in the area push the dust off the lake to the north, where there is essentially no monitoring in place. By the time the wind turns and brings the dust south where monitoring is better, it has dissipated such that a good understanding of the total amounts is hard to come by — even as the effects on the city are abundantly clear.

“After a big dust storm, you can see the line of cars at the car wash,” Perry said. “It’s amazing.”

There is also the question of what the dust contains. Research is ongoing on the arsenic and other heavy metals that could contribute to some of the human health effects; as a so-called terminal lake, without any outflowing water, the Great Salt Lake probably still contains any contaminants that have entered it since industrial activity began nearby.

Molly Blakowski, a Ph.D. student in watershed science at Utah State University and a board member of Friends of Great Salt Lake, said that dust particles have enough surface area that they can easily pick up other pollutants as they float through the air.

“We have all those oil refinery smelters, waste incinerators, those are all emitting things into the atmosphere that the dust can pick up,” she said, sitting in a coffee shop in downtown Salt Lake City. “Eventually, that dust will maybe settle in the Salt Lake area, or settle in the Wasatch Mountains, or be transported further. It’s getting dirtier as it gets further away from the lake bed.”

While 10-micron-wide PM10 particles are the pollutant of primary concern, the dust also contains smaller PM2.5 particles, which can penetrate deeper into the lungs and cause even more health issues. The larger particles stay aloft for a few hours, capable of moving up to around 150 miles in total; the smaller bits won’t come down until a raindrop brings them down, after an average of a couple of weeks. “That will be transported globally,” Perry said. It isn’t clear if that means this particular dust will have health effects many hundreds or thousands of miles downwind; one of the various ongoing research projects involves creating a sort of “fingerprint” of the dust, to differentiate it from other sources and better understand its long-term and long-distance effects.

Blakowski, Perry and other researchers spend hundreds of days out on the dry expanse of the Great Salt Lake’s exposed lake bed, hoping to paint a much more complete picture of the dust — how much, how often, how dangerous. They walk and bike carefully in colleagues’ footprints and wheel treads, trying to minimize any damage to the protective crust keeping the dust in place.

The work is not without its hazards: Perry recounted getting stuck out in a severe lightning storm, the tallest thing for miles (“That one was my fault”), when he decided to abandon his equipment and hustle back to his car. In his office, he picked up two bullets from a shelf where they sat next to a coyote skull — they were shot at him from over a mile away on shore, by whom he isn’t sure. On his wall are a couple dozen photographs of scenes from the lake, remarkably varied in color, landscape and content.

“Every time I go out there, almost every single time I see something new and different that I’ve never seen,” he said.

While the researchers look to fill in the knowledge gaps, the state is now pondering some of the policy levers that might fix the problem. The Great Salt Lake Strike Team, made up of experts from both Utah State and the University of Utah, has analyzed a number of those levers; in their recommendations on dust-control measures for certain hot spots, they specifically cite the lessons learned at Owens Lake. The best possible solution, though, is to treat the drying of Owens Lake as a cautionary tale and make every effort to not let the Great Salt Lake reach its breaking point.

Death on the horizon

A report from researchers at Brigham Young University, released in January, garnered a lot of attention by saying that without intervention, the Great Salt Lake was on track to disappear within five years. Perry called that specific conclusion and some recent reporting describing a potential dust “nuclear bomb” as “bunk” because of a quirk of the lake’s salty nature: As the water level falls, its salinity will increase, and with increasing salinity evaporation decreases, meaning there is something of a limit to how far the lake level can fall. “There will always be water out there,” he said.

The real tipping point, though, is the lake’s surprisingly vibrant ecosystem. Salty as it is, the Great Salt Lake is far from dead; it is home to brine shrimp — an industry worth more than $50 million per year to the region — and brine flies, creatures on the bottom of a food chain that supports tens of millions of birds. And that increasing salinity is threatening that ecosystem’s entire existence.

An exposed bit of lakebed next to Antelope Island in the Great Salt Lake, on March 2. — A bit of lakebed is exposed next to Antelope Island in the Great Salt Lake on March 2.

Driving out across the causeway to Antelope Island — itself home to a thriving population of bison, among many other animals — all the various issues seemed immediately visible: Thousands of those birds rested and flocked in the shallows to the north of the causeway, and huge swathes of exposed lake bed were clearly visible spreading outward from the island’s beaches, like the lowest of low tides had shown up and decided to stay awhile.

“It will become dead in five years if we don’t do anything,” Perry said. “At that point it’s like the Dead Sea. … There’s no brine shrimp. There’s no brine flies. And there’s no birds.”

Back in California at Owens Lake, a byproduct of the dust suppression measures has been the return of some of its wildlife. As we crisscrossed the raised dirt roads past the flooded bits of the lake, Kiddoo and I saw around 20 bird species, if not more, of the 100 or so known to stop by every year — brilliant cerulean mountain bluebirds, snow geese and what Kiddoo guessed were yellowlegs. Ravens flew by, and at least four or five duck and other waterfowl species enjoyed the flooded areas. At one point, Bella the dog bounded back to us soaked and happy, having chased some ducks out into the water.

Along with birds, Owens Lake now plays home to many other creatures, including coyotes, ring-tailed cats, rabbits, bears, elk, sidewinders and more. Back in the lake’s dustier days, all of these animals would have stayed far away.

Because of its unique nature, letting the Great Salt Lake die might mean its ecosystem never makes such a comeback. “I do not think it is an overstatement to say that there is an ecological emergency at Great Salt Lake right now,” Blakowski told me. “But that is going to expand into a public health emergency if left unaddressed.”

Don’t breathe

The specifics of the public health emergency at these dry lakes are strangely hard to come by. The effects of PM10 and PM2.5 are well understood, but hard data on what the dust has done or is doing to people essentially don’t exist — at Owens Lake, because there simply aren’t enough people around to study it well, and in Salt Lake City, because researchers would need more time to see things like heart disease and cancers develop.

Kiddoo said that some very basic research has gone on, such as a small project looking into increased hospitalizations on dusty days, but in large part the health emergency is an anecdotal one.

Michelle Hykes, a manager at the Mt. Whitney Restaurant in Lone Pine, chased me out the door to talk when she overheard I was there to learn about the dust. She told me the area has a lot of autoimmune disorders and breathing problems. “I truly believe we got sick from that lake,” she said.

Her son, Kelby, who also works at the restaurant, said they used to get warned not to go outside on bad days. “The air quality here is really good — but not when the wind blows,” he said. Reporting in the late 1980s highlighted some residents’ health issues, and “too many people dying in this town of lung disorders.”

Bella the dog eyes up some waterfowl in a flooded portion of Owens Lake in California on February 28. — Bella the dog eyes up some waterfowl in a flooded portion of Owens Lake in California on Feb. 28.

A 1998 report from the GBUAPCD did estimate the increase in cancer risk in tiny Keeler (population 50), a collection of mobile and other homes that was once a mining town directly on the eastern shore of Owens Lake. It found that the arsenic, cadmium and other toxic substances in the dust would lead to an additional 24 cases of cancer per million people — far above the threshold of one excess case per million that would be considered a “significant” risk.

In Salt Lake City, Perry said the increasing understanding of the potential health exposures is what has started to shift both public and political momentum. “Wildlife biologists have been sounding this alarm for 20 years,” he said. “Honestly, dying birds just doesn’t seem to resonate with people. They just don’t seem to care. But when it came to air quality, and ‘What am I breathing?’ and ‘What are my kids breathing?’ — that resonated.”

Still time to intervene

It has resonated enough that, in spite of the ecological nightmare scenario and the dust “time bomb,” there is hope for the Great Salt Lake.

“If you had talked to me four years ago, I would have said, ‘It’s dead.’ You know, nobody cares. It’s on the steep decline. Nobody’s even aware of the issue,” Perry said. And now? “I’m cautiously optimistic about the future of the lake. … It just takes the collective will, because we do have control over the situation.” In a way, climate change’s somewhat muted contribution to the problem to this point is a bright spot; localized water usage is easier to fix than warming temperatures.

Along with strong public support for lake-saving measures, the state legislature is also on board — mostly. In its previous session, the legislature made what Perry called “the most sweeping changes to water law that have ever happened in the history of our state of Utah.” This included investing heavily in water conservation measures, allocating money to buy up water rights and other moves.

This year’s session, which ended the day I spoke with Perry in his office, was somewhat disappointing. Most notably, a nonbinding resolution that would have set target water levels at 4,198 feet above sea level, around 8 feet higher than it is today, was blocked in committee by Republicans claiming it would make the lake too much of a priority. That water level would stave off the ecosystem collapse but would still leave 50 percent of the dust hot spots exposed.

Other proposals were also tabled, thanks in large part to the temporary reprieve of a remarkably snowy winter. “Mother Nature really helped us out,” one lawmaker said. The wet winter means that once the snow starts to melt, the lake can expect to rebound by 1 or 2 feet this year, following years of sharp declines. But huge cuts in water usage — upward of 30 percent, much of which will have to come from the agriculture sector, which uses 80 percent of the region’s water — will still be necessary to stave off the worst outcomes.

Blakowski, the Utah State Ph.D. student, shares Perry’s optimism, since the attention is being paid before catastrophe strikes and there are readily available lessons from dust prevention and control in California.

“It’s absolutely imperative to do everything we can right now to protect the ecosystem,” she said. “As we’re doing that, we need to be planning to make sure that we are not the next Owens Lake.”

Thanks to Lillian Barkley for copy editing this article.

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Utah’s Great Salt Lake may turn into a toxic dust bomb. Can a dried-up California lake help stop it?