If you thought the largest port in eastern Canada could pick up the slack for shuttered US ports, think again, at least for now.

Workers at the Port of Montreal went on strike on Monday, just hours before their counterparts at terminals on the US East Coast and Gulf of Mexico were scheduled to do the same.

The Maritime Employers Association said the strike impacted the Termont-operated Viau and Maisonneuve terminals, which handle about 41% of the port’s container traffic.

The three-day strike is expected to last until Thursday.

“We tried all possible means of averting tomorrow’s planned strike,” the group said on X. “Our efforts in mediation and at an emergency hearing this afternoon at the Canada Industrial Relations Board did not bear fruit.”

The hearing came after unsuccessful efforts to reach a deal with the International Longshoremen’s Union with the support of the Federal Mediation and Conciliation Service.

“We sincerely hoped to find common ground between the parties so that we could maintain operations. We are disappointed with this outcome,” the employer’s association said.

“Our priority remains the conclusion of a negotiated collective agreement within the briefest possible delay.”

MSC Mediterranean Shipping Company, the Swiss liner giant, is the biggest user of the impacted terminals.

The dockers’ contract at the terminal expired in December. Their union is part of the Canadian Union of Public Employees (CUPE).

The last time the collective bargaining contract was up for renewal, the government of Prime Minister Justin Trudeau intervened to prevent a strike.

“CUPE is calling on the federal government to resist pressure from CEOs and their conservative allies, and not intervene in the labour dispute at the Port of Montreal,” the umbrella union said on Friday.

The union said 98% of 1,200 dockworkers voted in favour of a strike.

“The Supreme Court of Canada has been crystal clear: the right to strike is constitutionally protected in Canada,” said CUPE national secretary and treasurer Candace Rennick.

“The prime minister and the labour minister should ask themselves: do they stand with workers and with the Charter, or with CEOs and rich companies who are trying to suppress the rights and wages of their employees?”