City and county leaders Wednesday unveiled warning signs at several South Bay spots where high levels of hydrogen sulfide gas from the Tijuana River Valley have been recorded.
San Diego County Supervisor Paloma Aguirre and San Diego Mayor Todd Gloria revealed the new signs at Tijuana River Valley Regional Park and at Saturn Boulevard in San Diego.
Since 2018, more than 200 billion gallons of toxic sewage, trash and unmanaged stormwater have flowed across the United States-Mexico border into the Tijuana River. The impact on neighboring communities includes long-lasting beach closures and lingering effects on public health, the environment and water quality.
In September 2024, high levels of noxious gases such as hydrogen sulfide and hydrogen cyanide were measured by scientific teams in the river valley. The chemicals created a rotten egg smell noticeable miles from the border.
Ultimately, crews from San Diego County determined there was no immediate health risk, but many residents had doubts. In two U.S. Centers for Disease Control-led surveys, some reported lingering health issues they believed were tied to the ongoing sewage pollution.
Those surveys spurred the county and city to work together on the signs. They include a QR code to take people to a county website dedicated to health and environmental concerns in the area.
The website explains what efforts have been undertaken in the Tijuana River Valley and directs people to the Air Pollution Control District website where they can claim a free air purifier.
In July, Democratic leaders in both houses of Congress introduced legislation to help combat the ongoing Tijuana River sewage pollution by appointing the Environmental Protection Agency as the lead agency on the crisis.
EPA Administrator Lee Zeldin also met with Mexico’s Secretary of the Environment and National Resources, Alicia Bárcena Ibarra, at the Council of the Commission for Environmental Cooperation.
Both nations agreed to expedite stormwater and sewage infrastructure projects on both sides of the border. Per the terms of that agreement, the U.S. will release previously withheld EPA Border Water Infrastructure Program funding to complete the rehabilitation of Pump Station 1 and Tijuana River collection pipes.
In exchange, Mexico agreed to fund and begin construction on two projects this year.
In addition, earlier this year, Sen. Cory Booker, D-New Jersey, visited Imperial Beach to see the crisis up close.
Sens. Alex Padilla and Adam Schiff, both D-California, and Booker, along with Rep. Juan Vargas, D-San Diego, introduced the Border Water Quality Restoration and Protection Act of 2025.
In it, the legislators call for the EPA to create a new geographic program to manage each watershed through a comprehensive water quality management plan.
