Two Democratic members of Iowa 's congressional delegation said Thursday they have asked the U.S. Justice Department to block Whirlpool Corp.'s proposed purchase of Maytag Corp. Rep. Leonard Boswell and Sen. Tom Harkin sent their request in a letter to Assistant Attorney General Tom Barnett. The Justice Department is investigating whether the merger of Whirlpool, the nation's leading appliance maker, and Maytag, the third largest, would concentrate too much of the appliance business in one company and violate antitrust laws. Industry observers have expressed skepticism that regulators would approve the merger. Stephen Calkins, a law professor at Wayne State University and a former Federal Trade Commission attorney, has said that regulators likely would have grave concerns about concentrating so much of the laundry market in one company.