Sewage pollution plagues schools in this California beach town

from Deborah BrennanCalMatters

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Last week, a fog crept over the Tijuana Estuary in Imperial Beach, emitting a pungent smell of rotten eggs as hydrogen sulfide rose from the polluted Tijuana River.

Virginia Castellanos, the school nurse for Bayside STEAM Academy near the estuary, worries that students will get headaches, stomach upset or breathing problems from the foul smell. She had another pressing concern: her own seven-year-old daughter was sick at home with asthma that flares up when the pollution spikes.

“I’ve had headaches and nausea all week,” Castellanos said. “The smell was so bad. And I was already expecting my daughter to get sick, and sure enough, in the last few days she’s been showing symptoms and she’s like, ‘Mom, I need my inhaler.'”

Later that day, Thursday, March 19, air pollution monitoring data showed hydrogen sulfide levels of 500 parts per billion, more than 15 times the California state standard of 30 parts per billion. News reports indicate that last week’s high temperatures, combined with transboundary sewage flows from a broken pump at a sewage facility in Tijuana, contributed to the smell.

Castellanos had to leave work early the day before to bring her daughter home and expected to do so again Thursday to take her to the doctor. The risk went beyond the asthma attack itself; in previous cases, respiratory distress progressed to pneumonia and weeks of illness.

“When I smell it starting again, I can guarantee you she’s going to get sick,” Castellanos said.

The symptoms Castellanos sees in his students and his own family are common among residents of Imperial Beach and other parts of South San Diego affected by the Tijuana River pollution.

When untreated sewage enters the river in Mexico due to sewage system failure or spills, the health impacts are felt across the border. Imperial Beach residents describe asthma, migraines, rashes, nausea, eye irritation, dizziness and brain fog when the disgusting smell of hydrogen sulfide wafts from the water.

“Patients tell us,” said Dr. Kimberly Dixon, the physician who runs South Bay Urgent Care. “They come in and say, ‘The air smells awful, I need to use my inhaler more.’ The air smells terrible, I have a headache.”

The unpleasant smell often keeps children indoors, away from parks or beaches. At school, it forces them to stay in the classroom and off the playground and sometimes leaves them home sick. The coastal environment that attracted many families to the coastal community has become a hazard.

“We love working and living here and having our kids go to school close to home, but it’s toxic,” said Bethany Case, an Imperial Beach resident, Surfrider volunteer and mother of two teenage sons. “We live in this beach community and we don’t live the beach life.”

Parents try to cope with the effects of pollution by storing inhalers, using air purifiers and limiting outdoor activity. But they wonder if the exposure puts children at risk of worse health problems down the road.

“They smell that air and are exposed daily,” Castellanos said. “What damage is happening to their lungs? What damage is happening to their bodies, their eyes, their noses. We don’t know what’s going to happen next. What health impacts are going to happen to these children?

Excursion, then rash

For 9-year-old Alan Gonzalez, the trouble began after a visit to the classroom.

The salt marsh is Bayside Academy’s backyard. It’s a haven for wildlife, where herons, ducks and other shorebirds wade in ponds dotted with aquatic plants. West fence lizards bask in the sun on the trail and cottontail rabbits dart across the wetland grass.

On a recent nature walk, Allen and his classmates uprooted invasive flowers and planted native vegetation, said his mother, Farren Espinosa. He felt uncomfortable when he got home, but he is on the autism spectrum and finds it difficult to express his experiences.

“The next day he was really upset and irritated” and told her his whole body itched, she said. “So when I checked it, there was a rash all over it.”

Espinoza called Allen’s doctor, who diagnosed him with an allergic reaction and prescribed Benadryl and a topical lotion.

A week later, Alan was still upset. He scraped so much that he cut himself. Espinoza had to hug him to keep his hands still.

“I couldn’t scratch for a while because my mom was threatening me to go to the doctor,” Allen said.

Espinoza eventually took her son to a doctor, who gave him a new diagnosis and a course of antibiotics.

“He said he’s seen other kids with that kind of rash and usually it’s because they’ve been to the beach and been exposed to bacteria,” she said. “It’s been foggy lately, so it could actually be airborne bacteria. Yeah, they say it could be aerosolized.”

Even after the rash subsided, it left Allen with new fears about the natural environment near his school and home. Espinoza hoped to enroll him in a Saturday nature program where children explore the estuary and learn about habitats and wildlife.

“He doesn’t want to do that anymore because he’s afraid of a backlash.”

Impact on student health

The Tijuana River has posed complex challenges since the United States and Mexico began jointly managing its flows more than 80 years ago. A sewage system on both sides of the border kept pollution under control for decades, but those facilities began to fail in the early 2000s, polluting beaches and dissuading swimmers and surfers. The problems escalated about a decade ago, after major spills from demolished sewage plants.

The unsafe conditions closed parts of Imperial Beach’s shoreline for three years, and in 2024 researchers revealed that the pollution could become airborne, confirming the concerns of residents who complained of foul odors and baffling illnesses.

“I didn’t notice the smell until it got really bad three years ago,” Castellanos said. “It never occurred to me that it came from the sewers.”

As the problem escalated, the San Diego Health and Human Services Agency asked the Centers for Disease Control and Prevention to help measure it. There are no studies that comprehensively document the impact on schools and students, but two public health studies released in October 2024 examined how Tijuana River sewage pollution is disrupting the lives of residents, including school-age children.

A CASPER studyor Community Assessment of Public Health Emergency Response, found that about 20 percent of area households reported disruptions to school or work in the previous month due to sewage contamination, and nearly 8 percent experienced disruptions to day care.

Another called an ACE investigationor chemical exposure assessment, reports even more widespread problems. Nearly two-thirds of residents surveyed said their children missed work or daycare because of symptoms they believed were related to the Tijuana River sewage crisis.

South Bay Union School District tracks pollution levels using monitoring data from the San Diego County Air Pollution Control District, Amy Cooper, executive assistant to the superintendent, said in an email to CalMatters. The air district has surveillance devices on the grounds of the district near Berry Elementary, the campus closest to the source of the contamination. The schools also received more than half a million dollars from the air district to purchase 199 air purifiers and a five-year supply of replacement filters.

When hydrogen sulfide levels exceed state standards, officials call a “rainy day schedule” to keep kids in the classroom and run air purifiers in all indoor spaces, Cooper said. This happened last Thursday, March 19, when steam and a pump malfunction caused the smell in the drain.

Public school funding is based on average daily attendance, so when students are absent due to pollution-related illness, it can mean lost revenue. Cooper said the district tracks illness-related absences based on what parents report, but a 2024 search of its database found no cases of “borderline sewage” or “sewage” as reasons for absences.

“Because we cannot attribute specific absences to the pollution crisis and have no evidence that the pollution directly affects the ADA, we cannot file an ADA reimbursement claim as we would in the case of a natural disaster such as a wildfire,” she wrote in an email to CalMatters.

Even when students stay in class, symptoms caused by the smell of hydrogen sulfide can interfere with learning, Dr. Dixon said.

“They’re walking to school in the middle of it and then they have brain fog when they get there,” she said. “And then they go to school and they’re expected to perform.”

Despite steps by schools to mitigate exposure to pollution, parents lament that their children are missing out on opportunities for outdoor activities and adventures. Espinosa grew up in Imperial Beach and remembers a childhood spent on the water, with beach trips a regular part of her school schedule. He hoped Alan enjoyed the same opportunities.

“As a parent, you want your children to experience all the beautiful things you had in your own childhood,” she said. “You try to recreate those moments and we really can’t do it. I really can’t take him to the bay because it’s dirty and it smells.”

This article was originally published on CalMatters and is republished under Creative Commons Attribution-NonCommercial-No Derivatives license.