Industrial activity, as well as the flow of people and cargo between Tijuana and San Diego, provides excellent cover for illegal activity. "The bottom line is, you can probably shoot a bullet in the air and it’ll land on a warehouse that’s doing something illegal in this area," Tim Durst, then the supervisor of the San Diego Tunnel Task Force, told GQ in 2014.
A military truck is parked outside a recycling plant where soldiers found a tunnel under construction at the Otay Mesa industrial park in Tijuana, July 12, 2012. The Mexican army located the tunnel in this border, which would be used for smuggling drugs, weapons and persons into the US, local media reported.