Liner operators that allow containers to remain at the US ports of Los Angeles and Long Beach face having to pay a surcharge under plans unveiled Monday.
The two US west coast ports said the move was designed to "improve cargo movement amid congestion and record volume".
Media reports Monday said almost 80 containerships were waiting in San Pedro Bay to berth at the two ports, while a further 29 ships were at berths.
Under the new policy, the ports will charge liner companies for each container that falls into one of two categories.
In the case of containers scheduled to move by truck, ocean carriers will be charged for every container dwelling nine days or more.
For containers moving by rail, ocean carriers will be charged if the container has dwelled for three days or more.
Beginning 1 November 2021, the ports will charge liner companies with cargo in those two categories $100 per container, increasing in $100 increments per container per day.
Before the pandemic-induced import surge began in mid-2020, on average, containers sat on container terminals for between two to four days.
“Those numbers have increased significantly, making it difficult to clear cargo off the terminals and bring in ships at anchor,” the two ports said.
Port of Los Angeles executive director Gene Seroka said the port had to expedite the movement of cargo through the ports to work down the number of ships at anchor.
"Approximately 40% of the containers on our terminals today fall into the two categories. If we can clear this idling cargo, we’ll have much more space on our terminals to accept empties, handle exports, and improve fluidity for the wide range of cargo owners who utilize our ports," he said.
Port of Long Beach executive director Mario Cordero said the ports were "running out of space" and this move will make room for the containers sitting on those ships at anchor.
"With the escalating backlog of ships off the coast, we must take immediate action to prompt the rapid removal of containers from our marine terminals," he said.
The move has the backing of the port envoy to the Biden-Harris Supply Chain Disruptions Task Force, John D. Porcari, who said: "These actions aim to expedite the movement of goods and reduce congestion in our ports.
"As our economy continues to grow, increased demand and disruptions caused by the pandemic are putting our supply chains to the test," he said.
"While we've seen new records set in terms of throughput this year at West Coast ports, we need more players throughout the supply chain to keep stepping up."
The two ports said the fees collected from dwelling cargo will be "re-invested by the two ports for programs designed to enhance efficiency, accelerate cargo velocity, and address congestion impacts throughout the San Pedro Bay".