DA Summer Stephan Seeks Records on Potential Industrial Pollution from Tijuana Businesses with U.S. Ownership

San Diego County District Attorney Summer Stephan announced today that her office is seeking records from Mexico’s federal environmental protection agency to help determine whether industrial businesses operating in Tijuana with U.S. parent companies or ownership interests may be contributing to pollution affecting the Tijuana River and Alamar River.

The request to Mexico’s Federal Attorney for Environmental Protection, known as PROFEPA, seeks records of environmental inspections, enforcement actions, sanctions, citizen complaints and potential sources of industrial pollution from January 2023 through September 2026. The information will help the District Attorney’s Office evaluate whether potential violations of environmental and consumer protection laws fall within its enforcement authority and what legal options may be available.

This action by the District Attorney’s Environmental and Consumer Protection Division was triggered by reliable evidence published by San Diego Coastkeeper on September 10, 2026, which documents the results of its 2025 Tijuana River Water Quality Monitoring Report. The findings continue to confirm the ongoing sewage contamination crisis and provide further evidence of industrial pollution, with detections of metals and industrial chemicals indicating inadequate wastewater treatment at Tijuana’s manufacturing maquiladoras. These pollutants appear to be entering the sanitary sewer system or being dumped directly into surface waters.

The DA’s office has engaged for several years in fact gathering as to any criminal or civil enforcement actions that can be taken within our state jurisdiction to this cross-border crisis. This new report by San Diego Coastkeeper helped focus the District Attorney’s investigation on the connection between the maquiladoras, particularly those with U.S. ownership, and the identified environmental pollutants identified in the region. These contaminants include volatile and semi-volatile compounds like heavy metals, pesticides, PFAs, acetone, phenols, benzoic acid and other harmful pollutants that are disproportionately harming our South Bay communities.

The key findings by this report warrant further investigation including the following findings: Industrial chemical detections indicate inadequate wastewater treatment at Tijuana’s manufacturing maquiladoras. These pollutants are entering the sanitary sewer system or being discharged directly into surface waters.

The effort comes as rain is forecast to move into San Diego County this weekend. Wet-weather events can worsen the region’s longstanding cross-border pollution crisis, carrying untreated sewage, trash and other contaminants from Mexico into the Tijuana River Valley and toward San Diego County communities and coastal waters. State water-quality records have documented tens of billions of gallons of transboundary flow in the Tijuana River.

“This request for information from the government of Mexico’s agency responsible for environmental laws is an important step to identify and gather evidence on the industries operating as maquiladoras with U.S. financial interests,” DA Stephan said. “We believe that when a company commits environmental violations that cross the border and continue to harm the water, air and people of San Diego County, those violations have consequences here that cannot be ignored. Just as we would pursue jurisdiction over a robbery that began in Mexico but continued into San Diego County, we believe the same principle should apply when environmental violations originating across the border continue to cause harm in our community. Environmental and consumer protection is about protecting people from harm. That responsibility doesn’t stop at the border. We are examining whether there are businesses whose conduct may violate the law and what we can do within our authority to protect our communities.”

WATCH DA SUMMER STEPHAN’S VIDEO MESSAGE HERE

The request seeks information about maquiladoras, or manufacturing and assembly operations in Mexico, with particular attention to facilities in Tijuana that have U.S. ownership or parent companies. Specifically, the office is seeking inspection reports, technical findings, administrative proceedings, fines, warnings, closures and records of complaints involving potential illegal discharges or improper handling of hazardous waste affecting the Tijuana and Alamar rivers.

The office is also seeking records of coordination between Mexican environmental authorities and U.S. agencies, along with information that may help investigators understand the nature of industrial operations and assess potential connections to reported environmental impacts.

For several years, the District Attorney’s Office has been reviewing legal, regulatory and technical materials related to cross-border wastewater impacts, including monitoring data, spill records and enforcement actions involving wastewater infrastructure and its operators. The newly requested records will help expand that review to potential industrial sources of pollution and the businesses that may be connected to them.

“I want to thank Supervisor Paloma Aguirre who has championed this important issue along with the County Board of Supervisors for their leadership and continued efforts to examine and address this longstanding cross-border pollution crisis,” DA Stephan said. “Protecting our communities and our environment requires sustained attention and collaboration across agencies and jurisdictions. Based on the significant recent San Diego Coastkeeper report, our office is laser focused on whether businesses may be contributing to this problem in violation of the law, and we look forward to building on these efforts to pursue accountability and protect the people of San Diego County.”

The San Diego County District Attorney’s Office enforces consumer protection and environmental laws within its jurisdiction. Its environmental enforcement includes investigating potential violations involving hazardous materials, waste disposal, water quality and other conduct that can threaten public health and the environment. We have brought many successful prosecutions against large companies for toxic dumping and other environmental and consumer protections. This is unique in its cross-border nature but not unique in terms of the substance and importance of the work.

“When business activity may be harming our environment, we have a responsibility to examine the facts, determine whether California law has been violated and pursue appropriate action when the evidence supports it,” DA Stephan said. “We are committed to using the tools available to us to protect the people and waterways of San Diego County.”