Sharing a stormwater drainage system with Nogales, Mexico, means that Nogales, Arizona, is a popular spot for cartels to push their contraband across the U.S. border undetected. The southern Nogales has about six times the population of its U.S. namesake and the city pushes right up against the border fence.
Recently, two tunnels were discovered in Nogales, bringing the Tucson-sector tunnel count to 125 found since 1990. In early December, the first of the two tunnels was discovered when U.S. Border Patrol and Mexican Federal Police collaborated for a routine sweep of the stormwater system.
The tunnel’s entrance was concealed in the floor of an existing drainage system by a pile of dirt; it was capped with a Styrofoam and concrete mixture, according to Customs and Border Protection (CBP).
It extended 10 feet underground and 20 feet into the United States, CBP said. At its exit, the tunnel was approximately three feet wide and over four feet tall.
Days later, Border Patrol found another tunnel about 50 feet away and alerted the Mexican Federal Police to check the location of the entrance from the southern side.
Both tunnels have been remediated with concrete filler, according to CBP.
Further west, in Yuma, Arizona, Border Patrol agent Jose Garibay recounted the story of a tunnel discovered in his sector in August 2018. The tunnel extended from San Luis, Mexico, to San Luis, Arizona. It was 600 feet long—the length of two football fields—and was shored up by vertical wood planks on the walls.
The tunnel popped up into an old KFC building in San Luis, and the exit point was about eight inches in diameter and just wide enough to bring up pounds of narcotics, said Garibay.
“A lot of them are hand-dug tunnels, which, regardless of how they’re dug, it takes a lot of precision to get them from the south side to the U.S. side and come up in the exact same spot that they want it to,” he said.
“Especially since they dug under a canal. So they had flowing water above them. It took a lot of engineering to be able to get it to work properly and not collapse.”
The tunnel was discovered through “human intelligence,” Garibay said, being careful not to reveal too many details. Federal and local law enforcement arrested a man who was transporting drugs out of the building.
When caught, the suspect was transporting more than three kilograms (more than six pounds) of fentanyl, six kilograms of cocaine, more than 20 kilograms of heroin, and 118 kilograms of methamphetamines, worth a combined $1.2 million.
During a traffic stop, a K-9 alerted officials to the drugs, which were in two toolboxes in the man’s pickup truck, said Scott Brown, Phoenix Homeland Security Investigations special agent in charge.
“Just the three kilograms of fentanyl translates to over 3 million dosage units,” Brown said at the time. “In a nation in the midst of an opioid crisis, obviously, this is a very significant seizure.”
The agent said the Mexico entrance of the tunnel was accessed via a trapdoor under a bed located in a residential compound.
Garibay said the tunnel was built by the Sinaloa cartel. According to the Drug Enforcement Administration, tunnels found along the border are generally associated with the Sinaloa cartel. Most tunnels are found in California and Arizona.
The tunnel was sealed at the border, then filled with concrete up to the exit point.
Some previously discovered tunnels, mostly in the San Diego area, have had lighting, ventilation, and rail systems. One such unfinished tunnel that was discovered in San Diego in 2018 was 627 feet long and went to a depth of 31 feet. A rail system ran the entire length of the tunnel, CBP said.
Garibay said no technology exists yet that can detect small cross-border tunnels, which are generally three feet wide and five feet tall.
“There’s nothing as of now that would allow us to go operational with it and detect it with a high rate of accuracy,” he said. “We’ve sent guys to Israel because [Israel has] a big problem with tunnels. So we were working with them. And they’re working on technology to try to detect tunnels more accurately.”
It’s impossible to tell how many pounds of drugs enter the United States through tunnels each year. Most of the drugs that CBP seizes along the border come through ports of entry in vehicles.
CBP officers and Border Patrol agents intercepted more than 82,100 pounds of drugs in November 2019—a 32 percent increase over October.