As the Salton Sea shrinks, a crisis deepens. The water levels of the 345-square-mile lake, located in an arid swath of agricultural land in Southern California’s Imperial County, have been receding for years, exposing the lakebed to strong winds that dry it, churn it to dust and drive the particles into surrounding communities. According to a recent academic study, the communities most impacted by the dust pollution are among the most socioeconomically disadvantaged in the state.

Yet some environmental researchers and advocates believe a draft environmental assessment from the federal government, released last month as part of a process for finalizing a new Colorado River water transfer deal, downplays the deal’s potential adverse health impacts on those communities. According to them, it would worsen dust pollution because it would continue a policy to divert water away from agricultural lands that drain into the Salton Sea, accelerating exposure of the dust-emitting lakebed.

Eric Edwards, an environmental economist at the University of California, Davis who co-authored the academic study published in May in the American Journal of Agricultural Economics, said the policy would exacerbate the conditions that have led to dust pollution around the Salton Sea. “They acknowledge as much in the environmental assessment. They basically say that this is going to accelerate the trajectory that the [water] depletion was already on,” he said. “All the same concerns are present with this policy.”

Edwards and his co-authors, in their analysis of the Salton Sea’s dust emissions, used a physics model to trace the likeliest paths of dust particles blown from the lakebed that was exposed when water levels receded between 1998 and 2018. They cross-referenced the projected paths of dust with air quality monitors to verify that the dust coincided with increased particulate pollution. They also traced which communities lay in the pollution’s path.

Using state health screening data, the researchers found that the Salton Sea’s dust pollution disproportionately fell on local areas that met California’s definition of a “Disadvantaged Community”—areas that are burdened by high exposure to pollution, poor health and low socioeconomic status, among other factors. (There is overlap between the census tracts that California identifies as disadvantaged, and those identified on the federal government’s environmental justice screening tool.) Much of the pollution likely fell on the eastern side of the state’s southern border, they found, including in the Imperial Valley, which is largely populated by Latino agricultural workers.

The Latino agricultural community consists of both monolingual speakers of Spanish and Purépecha (an Indigenous language from the Mexican state of Michoacán), according to previous studies that point to high rates of asthma in the region. According to the California Department of Public Health, children in Imperial County seek emergency-room care for asthma at twice the rate of the rest of California.

Edwards and his research team found that pollution around the Salton Sea began to increase around 2011, and that pollution disproportionately increased in disadvantaged communities after the Imperial Irrigation District (IID) began transferring water to San Diego and directing it away from the agricultural lands that run off into the Salton Sea. The result was likely an increasingly exposed lakebed—and a growing source of dust. 

The Salton Sea is itself a byproduct of an agricultural water diversion that went wrong. From 1905 to 1907, an irrigation canal carrying Colorado River water into the Imperial Valley flooded the area, creating what is now California’s largest lake.

The new draft environmental assessment, released late last month, is part of a process that would rubber-stamp IID’s Colorado River rights under a new agreement that seeks to conserve vast amounts of river water by 2026. The agreement would continue policies solidified under the previous water transfer deal. It would, for example, require some of the Salton Sea’s surrounding agricultural lands to lie fallow, reproducing the conditions that researchers believe have exacerbated the shrinking of the Salton Sea and led to a health crisis in the area.

Yet the assessment implies that the Salton Sea’s exposed lakebed is not a significant source of pollution that impacts environmental justice communities. Edwards noted that the report says there is no evidence that the acceleration of the exposed lakebed will exacerbate health problems.

“While this is technically true, because our paper only shows the increases in dust, not increases in health problems, there are other papers that show that increases in dust lead to increases in health problems,” he said. “So our paper suggests that by accelerating [lakebed] exposure, you move dust pollution—which we think occurs most immediately after [lakebed] exposure—forward three years. And that’s not costless.”  

The assessment comes after the U.S. Department of Energy announced that the Salton Sea region, which contains some of the world’s largest lithium deposits, “could produce more than 3,400 kilotons of lithium, enough to support over 375 million batteries for electric vehicles.” In 2022, the Biden-Harris Administration announced incentives for domestic extraction of minerals critical to electrical vehicle manufacturing, including lithium. Energy companies are now seeking to scale up commercial lithium extraction in the region.

Community advocates find some of the plan’s details troubling. Luis Olmedo, executive director of Comite Civico del Valle, an organization that works with environmental justice communities in the Imperial Valley, cited Edwards’ study in an emailed statement in which he disputed the assessment’s implication that increased lakebed exposure would not lead to poor health outcomes for environmental justice communities in the area.

The federal assessment also indicates that a full environmental review of the Colorado River transfer program is unnecessary because it wouldn’t affect environmental justice communities. 

“Unfortunately, I disagree,” Olmedo wrote in response. “The assessment assumes that the Salton Sea Air Quality Management Plan will fund restoration projects that will mitigate the short-term increase in exposed [lakebed]. However, the analysis predicts that those measures will not balance out the short-term increased exposure until 2045. This is very concerning.”

The environmental assessment “does not include any measures to improve the health of Salton Sea communities and improve the environmental conditions at the Salton Sea,” he continued. “A reasonable alternative would be to evaluate the ways to achieve water conservation goals AND support environmental justice needs, such as directly and immediately reducing the amount of exposed [lakebed] that is directly contributing to respiratory ailments in the Salton Sea region.”

The Bureau of Reclamation, in an emailed reply to questions, did not respond to the specific issues raised about the plan’s potential health impacts on Salton Sea environmental justice communities. A spokesperson for the federal agency wrote, “we don’t have any additional information to share currently,” and linked to instructions for submitting public comment. Public comments are being accepted until July 28.