One of AP Moller-Maersk’s container ships carrying goods from China to the U.S. lost part of its cargo in the Pacific Ocean during bad weather.

About 750 containers from the Maersk Essen fell overboard on Jan. 16 while sailing from Xiamen, China to Los Angeles, the company said in an emailed statement. All crew members are safe and a detailed assessment of the cargo is ongoing while the vessel continues its journey. The ship is expected at Mexico’s Lazaro Cardenas on Jan. 29 for cargo surveys, port operations and repairs.

Container ships are traveling fully laden with goods from China to the U.S. this year as freight rates surge to record highs and companies restock inventories. The incident comes after the ONE Apus container ship managed by NYK Shipmanagement Pte lost 1,816 containers at sea due to severe weather on Nov. 30 while en route to Long Beach, California, from Yantian, China.

‘Impossible’ Recovery

Winter in the North Pacific is notorious for bringing extreme weather and heavy seas, and large container ships are traveling at maximum speeds, Clive Reed, founder of Reed Marine Maritime Casualty Management Consultancy, said in an interview. Problems with rolling and bad weather can be overcome by the shipmaster slowing down, he said.

“However, current freight rates are high, and there is commercial pressure on the ships to arrive on time and consequently make more voyages,” Reed said. “These tight schedules leave the master little room to literally maneuver.”

Reed said recovering containers mid-ocean is an “economic non-starter.”

“It is close to impossible to retrieve containers lost overboard,” he said. “The majority will sink within a relatively short period of time.”