Thousands suffer nausea, delirium and other health issues from toxins in the Tijuana River

SAN DIEGO– The smell of rotten eggs permeates Steve Egger’s Southern California home, especially at night, as the nearby Tijuana River fills with sewage from Mexico before flowing into the Pacific Ocean.

Egger, 72, says he and his wife have frequent headaches and wake up congested, coughing up phlegm. Their home is equipped with a hospital-grade filtration system that circulates the air every 15 minutes.

Despite these measures, “most nights we breathe a foul odor,” he said. “It’s horrible.”

Since 2018, more than 100 billion gallons (378 billion liters) of raw sewage laden with industrial chemicals and waste have flowed into the Tijuana River, according to the International Boundary and Water Commission. The river passes through land where three generations of the Egger family once raised dairy cows. The United States and Mexico signed an agreement last year to address the long-standing problem by upgrading wastewater treatment plants to keep up with Tijuana’s growing population and industrial waste from the plants, many of which are owned by U.S. companies.

In the meantime, tens of thousands of people are exposed to sewage. Environmental Protection Agency Administrator Lee Zeldin said during a visit to San Diego in February that it would take about two years to resolve one of the nation’s most serious and long-running environmental crises, which affects a largely poor Latino population.

Raw sewage doesn’t just smell bad. It emits hydrogen sulfide, a toxic gas that can erode neurons in the nose and trigger asthma attacks. According to the Centers for Disease Control and Prevention, it can cause headaches, nausea, delirium, tremors, coughing, shortness of breath, skin and eye irritation, and even death. Its long-term health issues are only beginning to be understood.

There are no federal safety standards for hydrogen sulfide except for workers at sites where the risk is extreme, such as wastewater treatment plants or manure pits. A few states established standards decades ago, but they are outdated. A California proposal would require the state’s 56-year-old standard to reflect the health risks of gas. In Texas, lawmakers are also considering updating the law.

“I think when you look back when the standard was first set and then revised, it was all about nuisance — essentially, it was about odor,” said the author of the California bill, Democratic Sen. Steve Padilla, who represents the Tijuana River Valley. “I don’t think we understood scientifically what the health impacts were here, and now we do.”

Even if the bill passes, the new standard likely won’t be developed until 2030.

A “Stop the Stink” sign sits on Egger’s fence, part of a campaign launched by Citizens for Coastal Conservancy to demand that authorities clean up transboundary sewage.

The 195 km long river originates in the Mexican city of Tijuana, flows through California and empties into the ocean. Beaches in nearby San Diego County have been closed for years, and Navy SEALs who train in the water have fallen ill.

Since January alone, the Tijuana River has transported 10 billion gallons (38 billion liters) of mostly raw sewage and industrial waste across the U.S. border, according to data from the International Water and Boundary Commission. For comparison, a massive pipe that ruptured in January sent 244 million gallons (924 million liters) of untreated sewage into the Potomac River, affecting affluent, largely white communities. This spill triggered a federal response within weeks.

In 2024, sampling by San Diego County and the CDC representing approximately 40,000 households near the Tijuana River found that 71% could smell sewage inside their home and 69% had a family member who became ill from exposure.

Even at low levels, “you’ll feel like it’s in your sinuses. You can’t get rid of the smell. It’s going to be a constant irritation,” said Ryan Sinclair, associate professor of environmental microbiology at Loma Linda University’s school of public health.

The EPA said it was working with local and state officials to find ways to mitigate the odor.

San Diego County has distributed more than 10,000 air filters to homes this year. But the air remains a threat. The river foam is now visible from space.

In September 2024, Kimberly Prather, a chemistry professor at the University of California, San Diego, and a team of researchers installed air monitors in the neighborhood where Egger lives.

What they found stunned them: Hydrogen sulfide concentrations were 4,500 times higher than typical urban levels and 150 times higher than California atmospheric standards when river flows peaked at night.

Many residents, like Egger, felt vindicated.

“They were kind of lit up and told, ‘There’s gas. It’s a nuisance. It smells, but it’s not bad,'” Prather said.

She said her researchers had since detected thousands of other gases coming from the river that had no odor “and many of them were more toxic.”

Egger said doctors told him to move, although they did not give him a written diagnosis as suffering from hydrogen sulfide exposure.

But his family’s roots run deep. His wife grew up in Tijuana. His brother and his late brother’s family live in the houses next to the former Egger dairy. Nearby are the dilapidated milk barn and rusty farm equipment.

“This is where I’ve lived my whole life, with my family, my parents, my grandparents,” he said. “This is my home.”

When Egger was a child, he swam in the river which only flowed during the rainy season. Today mainly filled with sewage and industrial waste, it circulates all year round. He says the river should return to its historic route, which is closer to the border and further from most homes and schools. He thinks then it wouldn’t build up, creating hot spots of hydrogen sulfide gas.

Less than a half-mile from Egger’s home, the smell is overwhelming where the river bursts through pipes after being briefly forced underground near Saturn Boulevard.

Scientists call it “Saturn’s hot spot.” The stench permeates passing cars with their windows rolled up and lingers inside for days.

Dr. Matthew Dickson and his wife, Dr. Kimberly Dickson, run a clinic about a mile from the hot spot. Many of their patients suffer from migraines, nausea, wheezing, eye infections and brain fog. Asthmatics say they use their inhalers more when the air stinks.

“They said, ‘You know, I feel better when there’s no smell outside,’” Dr. Kimberly Dickson said.

In August 2023, a tropical storm caused the river to overflow into the streets. In a few days, the workload of doctors tripled.

Electronic medical records confirmed what doctors suspected. When the river’s flow increased, the number of patients treated for respiratory problems increased by 130%, they said.

“Every day that this problem is not addressed,” said Dr. Matthew Dickson, “more and more people are getting sick.”

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Pineda reported from Los Angeles.

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