U.S. Customs and Border Protection agents seized 333 pounds of cocaine hidden inside a shipping container full of beach chairs in what was described as the largest drug bust at the port to date, the agency announced Tuesday.

Customs agents found and seized the cocaine on June 18. So far, no arrests have been made.

“This seizure illustrates the complexities of Customs and Border Protection’s multifaceted missions, from ensuring that imported goods comply with U.S. trade regulations to interdicting dangerous drugs that harm our communities,” Casey Durst, director of field operations in Baltimore for Customs and Border Protection, said in a statement.

Customs officers, along with Homeland Security Investigations agents and state and local partners, examined the shipping container, which arrived from China via Panama. The beach chairs were bound for an address in Maryland, according to the release. Authorities found four black bags concealing 125 bricks of a white powdery substance that authorities said tested positive for cocaine, with an estimated street value of $10 million.

Customs spokesman Stephen Sapp said the agencies were doing a routine inspection when the cocaine was found.

China is one of the world’s leaders for exporting counterfeit goods, but the drugs may have been put on the ship in Panama, he said.

“We’ve seen drugs from mostly South and Central America,” Sapp said.

Customs uses noninvasive, cargo-scanning technology — what Sapp described as an X-ray truck — to screen the contents of containers. When an anomaly is detected by the scanner, authorities then search the container, Sapp said.

Prior to this incident, the largest cocaine seizure by Customs and Border Protection at the Port of Baltimore was a 311-pound discovery inside a container from Ecuador in April 2007, the agency said.

The 333-pound discovery occurred just one day after 17.5 tons of the drug, the largest amount in agency history, were seized by agents at the port of Philadelphia. Sapp said it is too early to say whether the two incidents are connected.