* Grain shippers accuse union of slowing operations
* Company has clashed with union over contract
* Workers say Columbia Grain never wanted an agreement
By Tom Polansek
CHICAGO, May 4 (Reuters) - Grain shipper Columbia Grain on Saturday locked out longshore workers in the Pacific Northwest in the latest escalation of a simmering labor dispute.
The company, owned by Japanese trader Marubeni Corp , said it took action because members of the International Longshore and Warehouse Union (ILWC) were purposefully slowing down operations at its terminal at the Port of Portland, a key outlet for exports to Asia.
Columbia Grain said it had contingency plans to keep operations running during the lockout.
"With bargaining stalled and the longshore workers engaging in 'inside game' tactics, including slowdowns, work-to-rule, and demands for repeated inspections of the same equipment - all designed to negatively impact Columbia Grain's operations - we have decided that a lockout is our best alternative," the company said in a statement.
A contract between the union and the Pacific Northwest Grain Handlers Association, a collective negotiating group that includes Columbia Grain, United Grain Corp, Louis Dreyfus and TEMCO, expired in September.
The two sides were unable to come to a contract agreement so terminal operators late last year declared an impasse and imposed the terms of their final contract offer.
TEMCO, a joint venture of U.S. agribusinesses Cargill Inc and CHS Inc, said in February that it reached a tentative agreement with the ILWU on its own. ILWU-represented employees at the Columbia Grain facility and the two Dreyfus elevators continued to work under the company's final contract offer terms.
The region's nine export terminals are a critical outlet for U.S. grain exports. Nearly half of U.S. wheat exports and about a quarter of all U.S. grain and oilseed exports leave the country via the Pacific Northwest.
Columbia Grain has 42.5 million bushels of storage capacity and exports nearly 160 million bushels of wheat, barley, corn and soybeans through a state-of-the-art grain elevator at Terminal 5 in Portland, according to Marubeni.
The union on Saturday said Columbia Grain never wanted to reach an agreement with the longshore workers and that the company hired replacement workers last fall while negotiations were in their early stages.
"Marubeni-Columbia Grain has done what it's wanted to do all along, and locked out local workers who have made this company profitable for decades," said Bruce Holte, president of ILWU Local 8 and a Port of Portland Commissioner.
The union in March filed an unfair labor practice charge against United Grain Corp, a unit of Japanese trading company Mitsui & Co, after its members were locked out of the company's Vancouver, Washington, grain export terminal.