Authorities find longest Southwest border smuggling tunnel

US authorities on Wednesday announced the discovery of the longest smuggling tunnel ever found on the Southwest border, stretching more than three-quarters of a mile from an industrial site in Tijuana, Mexico, to the San Diego area.

The tunnel featured an extensive rail cart system, forced air ventilation, high voltage electrical cables and panels, an elevator at the tunnel entrance and a drainage system.

While there were no arrests, no drugs found at the site and no confirmed exit point in the US, the length more than 14 football fields stunned authorities.

This one blows past (the second-longest), said Lance LeNoir, a Border Patrol operations supervisor. We never really thought they had the moxie to go that far. They continue to surprise me. The tunnel exposes limitations of President Donald Trump's border wall, which stretches several feet underground in the area and is considered effective against small, crudely built tunnels often called gopher holes.

The one announced Wednesday was found about 70 feet (21 meters) underground, well below the wall.

Following the discovery in August, Mexican law enforcement identified the entrance and US investigators mapped the tunnel that extends a total of 4,309 feet. (1,313 meters). The next longest tunnel in the US was discovered in San Diego in 2014. It was 2,966 feet (904 meters) long.

The newly discovered tunnel is about 5.5 feet (1.68 meters) tall and 2 feet (0.61 meters) wide and runs at an average depth of 70 feet (21.3 meters) below the surface, officials said.

Agents discovered several hundred sandbags blocking a suspected former exit of the tunnel in San Diego's Otay Mesa industrial warehouse area. It went under several warehouses in Otay Mesa, where sophisticated tunnels have typically ended, and extended into open fields.

US authorities say they are confident that the tunnel exited in San Diego at one time, based on its trajectory.

LeNoir, a veteran on the multiagency task force of tunnel investigators known as tunnel rats, said he made his way through about 50 feet (15 meters) of sugar sacks blocking the tunnel but couldn't go any farther.