Health Crisis Unfolds Along Tijuana River Due to Sewage Contamination
Thousands of residents in Southern California are experiencing significant health problems caused by toxins from sewage in the Tijuana River. The foul odor of rotten eggs permeates homes, particularly at night when the river foams with wastewater from Mexico before flowing into the Pacific Ocean.
Steve Eggers, 72, and his wife wake up congested, coughing with phlegm, and suffering frequent headaches. Despite having a hospital-grade air filtration system that circulates air every 15 minutes, Eggers stated, "most nights we breathe a horrible stench." His family has lived on what was once their dairy ranch for three generations, now affected by the polluted river.
Massive Sewage Volumes and International Agreement
Since 2018, over 100 billion gallons (378.5 million cubic meters) of raw sewage, containing industrial chemicals and trash, have been discharged into the Tijuana River, according to the International Boundary and Water Commission. Last year, Mexico and the United States signed an agreement to clean the river through modern wastewater treatment plants and build new facilities to address Tijuana's population growth and industrial waste—much from U.S.-owned factories.
However, tens of thousands remain exposed to the sewage. Lee Zeldin, administrator of the Environmental Protection Agency (EPA), noted during a February visit to San Diego that resolving one of the country's worst and longest environmental crises, affecting a predominantly poor Latino population, may take about two years.
Toxic Health Impacts and Regulatory Gaps
Untreated sewage emits hydrogen sulfide, a toxic gas that can damage nasal neurons and trigger asthma attacks. It also causes headaches, nausea, delirium, tremors, coughing, breathing difficulties, and skin and eye irritation, per the U.S. Centers for Disease Control and Prevention (CDC). Long-term health impacts are only beginning to be understood.
There is no federal safety standard for hydrogen sulfide, except for workers in high-risk sites like wastewater plants. Some states set their own standards decades ago, now outdated. A bill debated in California would require updating the 56-year-old state standard to reflect health risks. Texas legislators are also considering updates for better public protection.
"I think if we look at when the standard was first set and then revised, it was all about nuisance; basically, it came down to odor," said Democratic Senator Steve Padilla, the bill's author. "I don't think we understood scientifically what the health repercussions were in this case, and now we do." If passed, new standards might not be implemented until 2030.
Pollution Scale and Community Response
A sign reading "Stop the Stench" hangs on Eggers' fence, part of a campaign by Citizens for Coastal Conservancy demanding action from officials. The 120-mile (195-kilometer) river starts in Tijuana, crosses into California, and dumps pollution into the ocean. Nearby San Diego County beaches have been closed for years, and some Navy SEALs training in the water have fallen ill.
Since January, the Tijuana River has carried 10 billion gallons (37.85 billion liters)—mostly untreated sewage and industrial waste—across the U.S. border, per commission data. In comparison, a major pipeline break in January spilled 244 million gallons (924 million liters) of untreated sewage into Washington D.C.'s Potomac River, lined by wealthy, mostly white communities, prompting a federal emergency declaration within weeks.
A 2024 survey by San Diego County and the CDC, representing about 40,000 households near the river, found 71% could smell sewage indoors, and 69% had a family member sickened by exposure.
Even at low levels, "you'll feel it in your sinuses. You won't be able to get rid of the smell. It will be a constant irritation," said Ryan Sinclair, associate professor of environmental microbiology at Loma Linda University's School of Public Health.
The EPA is working with local and state officials to mitigate the odor. This year, San Diego County distributed over 10,000 air purifiers and filters to homes, yet air quality remains a threat, and river foam is visible from space.
Shocking Research Findings and Medical Advice
In September 2024, Kimberly Prather, a chemistry professor at the University of California San Diego, and her team installed air monitors in Eggers' neighborhood of Nestor. They discovered hydrogen sulfide concentrations 4,500 times higher than typical urban levels and 150 times above California air quality standards during peak nighttime river flow.
Residents like Eggers felt vindicated. "They were more or less being gaslit, being told 'there's gas, it's a nuisance, it smells, but it's not dangerous,'" Prather said. Her researchers have since detected thousands of other odorless gases from the river, many more toxic.
Doctors have advised Eggers to move, though he lacks a written diagnosis for hydrogen sulfide exposure. His symptoms disappear on vacation, but family roots run deep—his wife grew up in Tijuana, and relatives live nearby on the former Egger Dairy. As a child, Eggers swam in the river, which only flowed during rains; now, filled with sewage and industrial waste, it flows year-round. He advocates restoring the river to its historic channel, closer to the border and farther from homes and schools, to prevent stagnant pollution hotspots.
Less than half a mile from Eggers' home, the stench is potent where the river emerges from pipes near Saturn Boulevard, dubbed "the Saturn hot spot" by scientists. The odor infiltrates cars with closed windows and lingers for days.
Healthcare Burden and Patient Surges
Doctors Matthew and Kimberly Dickson run a clinic about a mile from the Saturn hot spot. Many patients suffer migraines, nausea, wheezing, eye infections, and mental confusion. Asthma patients report needing inhalers more often when the air stinks. "They tell us 'I feel better when there's no bad smell outside,'" said Dr. Kimberly Dickson.
In August 2023, a tropical storm caused the river to overflow and flood streets. Within days, the doctors' patient count tripled. Electronic medical records confirmed suspicions: when river flow increases, respiratory-related patient visits rise by 130%.
"Every day this isn't fixed, more people get sick," said Dr. Matthew Dickson. The Associated Press receives support from the Walton Family Foundation for environmental and water policy coverage, with the AP solely responsible for all content.
