More than 450 kilograms of cocaine valued at more than US$20 million was allegedly hidden beneath the floorboards of a commercial truck and flatbed trailer carrying rebar, according to U.S. federal authorities.

The seizure occurred at the Calexico Port of Entry and is the second-largest cocaine seizure in the Southern District of California this year.

According to U.S. authorities, the commercial truck was loaded with 269 bundles of rebar when U.S. Customs and Border Protection officers, working with Homeland Security Investigations and the Drug Enforcement Administration, selected it for inspection.

An X-ray examination revealed anomalies in the trailer floor, and a drug detection dog alerted to the shipment. After the rebar was removed, officers unscrewed the wooden floorboards and discovered 366 packages of suspected cocaine concealed inside.

Authorities seized 1,002.13 pounds (454.56 kilograms) of cocaine.

The driver and sole occupant of the truck, Jose Manuel Lopez Lopez, 44, of Mexicali, Mexico, was arrested and charged with importing cocaine into the United States. The offence carries a maximum penalty of life imprisonment and a mandatory minimum sentence of 10 years if convicted. Lopez pleaded not guilty during his initial appearance in federal court. The charges have not been proven in court.