U.S. Customs and Border Protection officers made a record-breaking bust in California Thursday evening. Officials seized more than 15 tons of marijuana hidden inside a truck claiming to carry mattresses at the Otay Mesa Port of Entry. The pot shipment has an estimated street value of nearly $19 million, news station KNSD in San Diego reported Friday.

It’s the largest narcotics bust in the history of the Otay Mesa border crossing and the second-largest at any border crossing in the United States, KNSD reported. Otay Mesa is one of three ports of entry in the San Diego-Tijuana region.

A 46-year-old Mexican citizen drove the tractor-trailer to the commercial port at about 6 p.m. Thursday with a cargo shipment labeled as mattresses and cushions. After an anomaly was detected during an x-ray examination, officials found nearly 1,300 plastic-wrapped cannabis packages stacked inside the truck from front to back and floor to ceiling, with just a few mattresses along the wall at one end, according to a U.S. Customs and Border Patrol statement obtained by U-T San Diego.

The driver, who had a valid border-crossing card, was arrested and handed over to U.S. Immigration and Customs Enforcement. His name was not released, the Times of San Diego reported.

The smuggling attempt was “definitely very risky” and is suspected of being tied to a drug cartel in Mexico, Lauren Mack, spokeswoman for U.S. Immigration and Customs Enforcement in San Diego, told U-T San Diego. “Obviously they felt confident they were going to succeed,” Mack reportedly said Friday.

The nearly 32,000 pounds of marijuana seized at Otay Mesa Thursday far surpassed the port’s previous record in 2003 of 19,999 pounds. The amount came close to the largest ever seized at a U.S. border crossing, which was in Imperial County where 35,265 pounds of pot was seized at the Calexico East Port of Entry in July 2013, according to U-T San Diego. One ton is equal to approximately 2,200 pounds.