FAIRFIELD, Iowa — Workers at a Dexter Apache Holding Co. commercial laundry manufacturing plant went on strike after voting 139-10 against a contract proposal. Picket lines went up Saturday night.The International Association of Machinists and Aerospace Workers Local 1293 represents about 210 workers at the Dexter Laundry Inc. plant. The union said the workers rejected the proposed five-year contract because it would have significantly increased insurance premiums and out-of-pocket costs for workers. The contract proposal called for a 90-cent an hour increase over the five years, the union added.Dexter officials issued a statement and said that they were disappointed in the strike, and that the offer to the laundry workers was better than the one ratified by their foundry workers recently. “It is pretty much business as usual in our company,” the company added. “We are making machines, servicing customer orders and evaluating alternative sources for increasing production capacity.”Negotiations between the company and union had been taking place for the last several weeks and the two parties had reached agreement on everything but pay and health insurance costs, the union reports.