SAN DIEGO (AP) — Authorities say a 7-ton load of marijuana, worth about $8.6 million, was found inside the trailer of a truck trying to cross into the U.S. from Mexico.

U.S. Customs and Border Protection officers said Friday the load was discovered during an X-ray inspection at the Otay Mesa border crossing in San Diego.

The truck’s driver, a 45-year-old Mexican citizen, was carrying a manifest that claimed he was hauling metal racks. Officials said officers saw “an anomaly” on the X-ray and a police dog detected drugs.

When officers opened the trailer, they found 722 packages of marijuana hidden inside boxes. In total, they say the truck had nearly 15,000 pounds (6,803.96 kilograms) of marijuana.

Authorities say the driver’s visa was canceled and he was turned over to federal investigators.