DES MOINES, Iowa (AP) _ A state worker's union has filed a complaint against Gov. Terry Branstad over asking workers to pay part of their health care premiums. The American Federation of State, County and Municipal Employees filed a complaint with the Iowa Public Employee Relations Board on Tuesday The complaint says health insurance is covered under collective bargaining laws and the governor is prohibited from approaching workers about making changes. Branstad signed an executive order last week allowing state workers to voluntarily pay 20 percent of their premiums. He says he and the lieutenant governor will do so beginning Aug. 1. Branstad spokesman Tim Albrecht says it's outrageous that Iowans, who pay their own health care costs, are forced to foot the bill for state workers.