Tijuana River’s toxic sewer sludge dangerous for migrants and border agents


Border Patrol agents say human smugglers are exploiting the Tijuana River Valley culvert system meant to drain raw sewage at the U.S.-Mexico border; putting agents, emergency responders and migrants at risk for drowning and exposure to highly toxic substances.

During a storm, sewage flows from Tijuana’s hillsides into their tributaries, or streams, and then across the border into a maze of drainage pipes and culverts in the United States. Millions of gallons of waste water flows across, some of it eventually emptying into the Pacific Ocean.

When it rains, smugglers encourage migrants to cross into the United States through the storm drains that run under the border infrastructure, according to Border Patrol.


Since October, at least 45 people have been apprehended in the area for trying to enter the country through the sewer and storm water tunnels, according to Agent Jarrett Decker, a public affairs officer in the Border Patrol’s San Diego Sector.

Not only are the migrants and agents exposed to an unknown toxic cocktail of sewage, carcinogenic chemical waste and industrial compounds, they also risk drowning by unpredictable and fast-moving storm water when it rains, Decker said.

“A lot of times, agents are risking their own lives to save someone here,” he said.

During a downpour on Thanksgiving night, Border Patrol agents, San Diego lifeguards and Chula Vista firefighters rescued dozens of people from fast-rushing water near a drain in the Canyon del Sol culvert — one of five canyon collector culverts in the Tijuana River Valley.

“The force of the water is just too strong,” said Amber Craig, a Border Patrol agent who has worked in the area for about 20 years. “The storm just made it insanely dangerous. Add in the storm water, and they had no chance.”

At least one person sustained life-threatening injuries, and one body was found in the water of a beach near the west end of the Tijuana River, authorities said. It was unclear if the deceased person was among those who tried to cross that same culvert during the storm.

“We could hear a woman screaming down in the tubes,” said Justin De La Torre, the Border Patrol agent in-charge from the Imperial Beach Station, describing the dramatic rescue.

“Down in the tubes” refers to a 72-foot vertical drop down a drain that was quickly filling with toxic storm water while migrants were trapped inside.

The giant pipe, 6 feet in diameter, is typically covered by a large rectangular grate, but during heavy rains that screen is lifted to allow the debris-filled storm water to flow.

Border Patrol agents say when it rains, smugglers know the grates will be opened in several culverts along the border, allowing people an opportunity to cross without having to cut them open.

“Every time there’s a storm, they know,” Craig said.

De La Torre said scouts sit on banks on the other side of the border looking to see when the Canyon del Sol grate is lifted. He said anyone who tries to cross through the culvert is forced to pay smugglers.

“The criminal organization that owns this crossing will check and make sure anyone who comes through here has already paid,” he said.

The giant drain is in between the primary border fence and the newer secondary border structure. Border crossers can easily walk through the culvert under the first border fence, but then they must drop down into the storm drain and travel through the tubes to bypass the secondary border wall.

Agents said besides the secondary border wall, they have sensors, cameras and other technology in the area to detect when people are trying to cross.

“There’s no reward for this,” De La Torre said. “They do get apprehended and on top of that, you’re exposing yourself to potential disease and maybe even permanent damage or serious injuries.”

Several agents said last week they are concerned about what kind of toxins and chemicals the migrants and agents are being exposed to when they wade through the water.

“We don’t want to have to make these rescues, but we’re put in this dangerous position,” Decker said. “It’s not right for the agents and it’s not right for the people being told to cross.”

Agents said smugglers never tell their clients about the high levels of bacteria from human waste and the dangerous carcinogenic chemicals in the water.

“The transnational criminal organizations that get you into the country do not care at all about your safety,” Decker said. “They don’t tell you how dangerous it is or about the rushing water.”

Human rights activists say while the U.S. government blames Mexican criminal organizations, some fault lies with their own restrictive immigration policies that force migrants into taking increasingly dangerous paths to the United States.

Agents who work in the area have reported skin rashes, chemical burns, respiratory problems, nausea and flesh-eating bacteria. The toxic runoff can eat through an agent’s boots, and then seep into their socks, causing chemical burns on their feet, agents said.

The agency has been conducting water-quality testing since early 2018 in the Tijuana River Valley. Along with high levels of bacteria from human feces, the testing found carcinogenic chemicals — such as the banned pesticide DDT and dangerous industrial compounds like hexavalent chromium.

The extent of the pollution has yet to be fully documented. Levels for any one contaminant were not dramatically high, according to water quality officials. But the list contained more than two dozen potentially dangerous substances, including uranium and the internationally banned pesticide Aldrin.

The new United States-Mexico-Canada trade agreement reached earlier this month commits the federal government to provide $300 million for the Border Water Infrastructure Program to address pollution on the U.S.-Mexico border, including in the Tijuana River Valley region.

Some border agents hope the money is spent to help prevent debris from rushing downstream during storms, removing the need to open the grates on the storm drains.

Fry writes for the San Diego Union-Tribune.