“The BCMEA remains committed to bargaining in good faith and seeking a fair and balanced deal that recognizes the expertise of the waterfront workforce, while ensuring West Coast ports remain competitive, resilient and affordable for all Canadians,” the port operators said in a statement responding to the strike authorization.

It’s the latest potential wrinkle for the global supply chain, which relies on shipping hubs to move billions of dollars worth of cargo every month.

A strike by Canadian dockworkers could have grave implications for the ports’ American counterparts on the West Coast, which have been locked in a labor dispute with their port operators since July. Canadian ports represented by the ILWU Canada collectively handle $225 billion worth of cargo each year, a portion of which is transported to their destinations by American trains and trucks.

Like U.S. dockworkers, the main priorities for ILWU Canada members revolve around wages and protection from automation.

What to know about the West Coast ports’ slowdown

Though the U.S. dockworkers union has not authorized a strike, port operators represented by the Pacific Maritime Association say union workers have caused delays and work stoppages at several major shipping hubs. Portions of the ports at Los Angeles, Long Beach, Calif., Oakland, Calif., and Seattle — gateways for container ships that bring imports from Asia — have intermittently shuttered or slowed in recent weeks amid ongoing contract negotiations.

If Canadian ports were to temporarily shut down, the inbound cargo would likely be redirected to the West Coast ports, leading to further congestion, said George Kochanowski, chief executive of Staxxon, a company that makes shipping containers.

“The shippers from Asia, country lines don’t mean anything to them, it’s about the final destination — North America. But there’s a fixed amount of land, of warehouses, of roads to get there,” Kochanowski said.

The economy relies on ships, trains and trucks to transport goods, and it only takes a small disruption to one part of the supply chain to cause congestion in the others.

Though contract negotiations in the United States have made significant progress on issues tied to automation, pay remains a sticking point, according to two people briefed on the negotiations, who were not authorized to speak publicly about the talks.

President Biden’s acting labor secretary Julie Su met with both parties in San Francisco on Tuesday to help mediate in the U.S. negotiations, a representative of the Department of Labor confirmed to The Washington Post.

Among retailers, there’s a growing concern that more labor disruptions and stoppages at Canadian and West Coast ports could impact “back to school” shopping, with merchandise like backpacks and shoes not arriving in time for their peak season. Shippers are eyeing ports in both Mexico and on the East Coast as alternatives, but the longer travel times are costly.

“The insiders are all saying that they’ll just go to the to the other coast, where the people seem to be more reasonable,” Kochanowski said. “But it’s a big expense, and the fear is that the consumer will not want to pay the price.”

Major companies that use the Canadian ports include furniture giant Ikea and retailer Canada Tire. Midwest manufacturers and automakers, which rely on West Coast ports and railways to deliver material inland, also stand be to be affected by port closures.