Contract talks between a group of U.S. Pacific Northwest grain exporters and a dockworkers' union remained stalemated after the first bargaining session in three months, aided by a federal mediator, broke down.

A second meeting that was scheduled has been canceled.

No further talks were scheduled between the International Longshore and Warehouse Union (ILWU) and three of the four grain companies in the Pacific Northwest Grain Handlers Association: United Grain, Louis Dreyfus and Columbia Grain.

Cargill-CHS joint venture TEMCO, the fourth member of the collective negotiating group representing the Puget Sound and Columbia River elevators, reached a tentative contract agreement with the ILWU independently last month.

The ILWU wants the other three companies to consider implementing the terms of the TEMCO contract.

"It's pure greed that's stopping these profitable foreign grain merchants from reaching a win-win agreement with workers as their American counterpart TEMCO has done," said ILWU International President Robert McEllrath.

The companies are insisting on work-rule changes that they say would improve efficiency and put them on a more level playing field with rival exporters in the region.

"We are disappointed that the union presented us with a proposal less favorable than their last proposal of Dec. 12, 2012 - one which we previously advised was unacceptable," said Pat McCormick, a spokesman for the grain companies.

"It continues to be our position that we need parity with our competitors in Longview and Kalama," he said, referring to the rival exporters that are not part of the Grain Handlers Association.

A previous contract between the union and the Grain Handlers Association, which represent six of the nine grain export elevators in the region, expired in September.

Unsuccessful negotiations led terminal operators late last year to declare an impasse and impose the terms of their final contract offer. ILWU-represented employees continue to work under those terms at the Louis Dreyfus and Columbia Grain terminals.

Non-union workers and managers are handling shipments from the United Grain terminal after that company locked out union workers because it said a union leader sabotaged equipment there.

Elevators in the PNW ship nearly half of U.S. wheat exports and a quarter of other grain and oilseed exports every year. The PNW is the most direct outlet for U.S. shipments to major markets in Asia. (Reuters)