A Seattle-bound cargo ship has spilled an estimated 90 shipping containers into the North Pacific between Russia and the United States.

Nine of the spilled containers are carrying flammable lithium-ion batteries and are considered dangerous cargo.

The Liberian-flagged Dyros was sailing to Seattle from Yantian in southern China when it encountered heavy seas Sunday night off Russia’s Kamchatka Peninsula.

The same rough seas that caused the 850-foot ship to spill 90 giant metal boxes damaged another 100 containers on board, according to Maersk spokesperson Povl Rasmussen in Copenhagen.

“Besides losing containers, there are damages to the vessel’s deck,” Rasmussen said in an email. “It needs inspection/repairs.”

Maersk is operating the Dyros under charter from Costamare, the vessel’s Athens-based owner. Both companies are among the world’s largest shipping firms.

”We view this as a very serious incident which will be investigated thoroughly,” Rasmussen said.

Costamare officials did not respond to a request for information on the spill.

The containers went overboard about 600 miles southeast of Russia's Kamchatka Peninsula and 600 miles southwest of Attu, the westernmost of Alaska’s Aleutian Islands.

The Dyros encountered winds approaching 50 miles per hour on March 19 and March 20, according to ship transponder data provided by MarineTraffic, a maritime analytics provider based in Athens.

According to MarineTraffic, the Dyros continued east for more than 1,000 miles after the spill, then made a sharp turn to starboard after nearing Unalaska Island, home of the Port of Dutch Harbor.

Peggy McLaughlin with the Port of Dutch Harbor said the port has had no communication with the Dyros.

McLaughlin said she expected the U.S. Coast Guard would issue a warning to mariners about the spilled cargo but had not done so yet.

Thousands of cargo ships each year ply the international waters where the containers spilled, part of the North Pacific's "great circle route," the most direct path between East Asia and North America.

Container spills are rare events. According to the World Shipping Council, cargo ships transported 226 million containers internationally in 2019, with less than one thousandth of 1% falling overboard.

Still, a lost container can remain a floating hazard to navigation for weeks and a source of ocean pollution for longer.

Containers lost at sea float for three months on average, according to Norwegian marine insurance firm Gard.

Beach cleanup crews on Vancouver Island are still finding debris from the Zim Kingston, a cargo ship that spilled 109 containers off the Olympic Peninsula in October, according to Josh Temple with British Columbia’s Coastal Restoration Society.

The Dyros was scheduled to reach the Port of Seattle on March 27, but the ship’s destination changed Thursday, according to its transponder data.

The Dyros is now expected to arrive at the Port of Lazaro Cardenas, on Mexico’s Pacific coast, on April 3.

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