Communities near California’s Salton Sea are exposed to hazardous hydrogen sulfide gas far more frequently than official data suggests, according to a new study from Brown University and partners.
Key Points at a Glance
- Hydrogen sulfide emissions around the Salton Sea exceed state air quality standards regularly
- Government sensors underestimate the frequency and magnitude of the emissions
- Exposure linked to respiratory, neurological and quality-of-life impacts
- Marginalized communities face elevated health risks without adequate monitoring
Residents near the Salton Sea—California’s largest lake—are inhaling dangerous levels of hydrogen sulfide, a toxic gas linked to serious health issues. A newly published study in GeoHealth finds that government air monitoring significantly underestimates these emissions, putting already vulnerable communities at greater risk than previously thought.
“This is a public health crisis that’s been hiding in plain sight,” said Dr. Mara Freilich of Brown University, one of the study’s co-authors. The research team, including scientists from UCLA, UC Berkeley, and Loma Linda University, collaborated with local nonprofit Alianza Coachella Valley to conduct a detailed, community-engaged air quality assessment across the region.
The Salton Sea was formed accidentally in 1905 and has since become a repository for agricultural runoff and wastewater. Over time, increasing salinity and decaying organic matter have turned it into a hotspot for hydrogen sulfide emissions. The gas, recognized for its rotten egg smell, can cause fatigue, nausea, respiratory irritation, and long-term neurological effects—even at low concentrations.
Regulatory data from the South Coast Air Quality Management District (SCAQMD) already indicated exceedances of state standards in communities such as Mecca, Indio, and the Torres Martinez Indian Reservation. But the new research reveals those figures only scratch the surface. Using both regulatory and independent sensors—including devices placed directly within the lake—researchers showed that hydrogen sulfide is being released much more often and in greater quantities than reported.
During August alone, the Torres Martinez site recorded over 250 hours each year of hydrogen sulfide levels above California’s air quality standard. Many exceedances occurred when wind patterns directed emissions into residential areas, further confirming the lake as the emission source. Worse still, many shoreline communities remain unmonitored by current government systems, raising serious questions about invisible exposure.
“This is a textbook case of environmental injustice,” said Aydee Palomino of Alianza Coachella Valley, a co-author of the study. “Predominantly Latinx and Indigenous communities are breathing toxic air that isn’t even being counted.”
The study urges expanded air quality monitoring, particularly near unmonitored communities. It also highlights the value of community science: partnerships between researchers and residents helped expose discrepancies that traditional methods missed.
Despite the study’s urgent findings, future efforts may be in jeopardy. Freilich disclosed that NASA recently terminated the grant supporting follow-up work, including plans to share results with local communities.
“It’s devastating,” said Diego Centeno, a Ph.D. candidate at UCLA and study co-author. “Just as we’re making progress, we’re losing critical support to continue.”
The Salton Sea’s shoreline continues to recede, and with it, the risk of worsening emissions grows. Without immediate action, communities already burdened by poverty and pollution may face an even darker environmental future.
Source: Brown University
