As beach closures in the San Diego area stretch past 1,000 days due to raw sewage flows from Mexico, residents of Imperial Beach have filed a lawsuit against Veolia Water, accusing the engineering consultant—who also manages the South Bay International Wastewater Treatment Plant on the U.S. side of the border for the International Boundary and Water Commission—of not doing enough to stop toxic sludge flows.

"Although it has received millions of dollars from the federal government to operate, manage and maintain the plant, Veolia has instead, caused, or contributed to, or failed to ameliorate, a public health and environmental crisis that continues to harm residents in Imperial Beach," says the suit filed on behalf of 10 residents. "Since 2018, the [federal agency] and Veolia have caused, or failed to prevent, over 500 illegal discharge incidents from the plant, resulting in over [one] billion gallons of raw sewage being dumped into the river that flows into South San Diego."

As a class action, other residents can still join the complaint. While action is only against Veolia Water—which provides water services to hundreds of municipalities and to other federal agencies—the suit says it will be amended to include the commission at a later date. Attorney Stephen B. Morris said the six-month waiting period to file suit against a federal agency was the reason for the delay.

"Veolia recognizes that transboundary pollution, caused by the continued population growth of Tijuana, Mexico, and the associated sewage that comes into the United States, is a serious problem," said Adam Lisberg, the firm's senior vice president of communications for municipal water. "Veolia looks forward to continuing to assist [the commission] with the [plant] operation and hopes that the substantial repairs, rehabilitation and expansion of the facility planned by [the commission] will bring relief to the affected communities in the near future."

Escalating Border Tension

The lawsuit states that by the commission's own timeline, the recently announced repairs would take at least five years to complete. Tension within border communities near the Tijuana River has escalated since Sept. 9 when researchers from San Diego State University, the University of California at San Diego's Scripps Institution of Oceanography and others reported finding high levels of toxic hydrogen sulfide and hydrogen cyanide in the air in the South Bay. 

The academic institutions and the California Environmental Protection Agency have been testing air and water in the South Bay for more than a year. The San Diego County Air Pollution Control District has also recommended that students and residents stay indoors for most of the year. While the county has supported efforts to deal with the effluent flow and backs construction projects like the recently announced South Bay plant expansion, Board of Supervisors Chairwoman Nora Vargas pushed back against the researchers' findings at a Sept. 10 press conference. 

"The air quality in the region is within safe limits and does not pose a public health threat at this time," she said. "As chairwoman, I want to reassure everyone that this is not an imminent threat, and it’s safe to be outside and attend school."

Vargas said county experts are gathering public health data and conducting research to provide the most accurate information and that she and the county are fighting to address the root of the issue—more pollution from the Tijuana side of the border. 

At the press conference, Vargas and Air Pollution Control District officials said researchers' results could have returned falsely high positive results for the presence of the toxic gas hydrogen cyanide, a byproduct of plastics, nylon and fumigant manufacturing around the Tijuana River Valley.

Disputed Numbers

The county Environmental Health and Quality Dept. said it is certain that air quality monitoring instruments that measure toxins in the air can show falsely high readings of hydrogen cyanide even when the gas is barely present if instruments are measuring air that also contains hydrogen sulfide. The latter is what they say caused the San Diego State high readings. This drew a strong response on Twitter from Kim Prather, chair in atmospheric chemistry and a distinguished professor at UCSD/Scripps and who leads its testing team.

"Just because [hydrogen sulfide] levels in South Bay are below the threshold for causing instant fatalities of all residents doesn't mean the air is safe @SupNoraVargas. Stop saying this." she wrote on Twitter. "You are causing serious harm to the community in so many ways. Please listen to [the] cries for help."

Prather further explained that researchers have identified "hot spots" in Imperial Beach where turbulence in the river releases extensive odor, as well as river spray aerosols containing viruses, bacteria and other pollutants, adding that the air currently is not safe to breathe due to a number of toxins causing headaches and sickness beyond just hydrogen cyanide. A 2023 research paper by Prather and the rest of the Scripps Institute team identified 40 to 70 million gallons of sewage that were discharged into the Pacific Ocean and became aerosolized since 2018, making the situation there akin to waterside communities before modern wastewater treatment existed.

The U.S. section of the border commission issued a strong statement Sept. 11 about finally stopping the sewage from coming across the border. 

Raw sewage flows from the Mexico side had been a problem throughout the early 2010s, but the situation began causing beach closures more frequently after a supply pipe rupture took offline a plant in Punta Bandera, Mexico in 2014. Former Mexican President Andres Manuel Lopez Obrador gave control of Punta Bandera plant reconstruction to the Mexican military in January.  

"The [commission] is very concerned about the high flows and sediment entering the United States from Mexico in the Tijuana River. We are implementing several steps to identify the sources of the flows, including working closely with Mexico and using satellite imagery," said the agency statement. "Once the sources are identified, we will request a plan of action from Tijuana's water utility to address needed repairs and monitor progress."