The Pacific Maritime Association and International Longshore and Warehouse Union announced Wednesday night they had reached a tentative agreement on a six-year contract covering workers at 29 West Coast ports.

The tentative deal is subject to ratification by the two parties. The PMA and ILWU said they would not release any details of the agreement at this time.

Acting Labor Secretary Julie Su “played a key role” in reaching an agreement, according to the joint statement. The Labor Department chief joined negotiators in San Francisco earlier this week after a series of disruptions affected port operations in early June.

“The tentative agreement delivers important stability for workers, for employers and for our country’s supply chain,” Su said in a statement. “This important milestone is welcome news to all, and on behalf of President Biden, we are pleased to congratulate both parties on what they have achieved.”

The tentative deal comes after more than 13 months of negotiations, one of the longest contract talks in recent memory. It also comes at a critical time for the U.S. supply chain, as businesses prepare for a surge of imports typical of a summer peak shipping season.

“We are pleased to have reached an agreement that recognizes the heroic efforts and personal sacrifices of the ILWU workforce in keeping our ports operating,” said PMA President James McKenna and ILWU President Willie Adams in a joint statement. “We are also pleased to turn our full attention back to the operation of the West Coast Ports.”