Federal auditors looking into Maryland's flawed health insurance exchange are subpoenaing documents as part of their probe and have sought information from the lead contractor hired by the state to build the site. North Dakota-based Noridian Healthcare Solutions, the former prime contractor with a multimillion-dollar deal to design Maryland's online insurance marketplace, received a request for documents related to the project from the inspector general of the U.S. Department of Health and Human Services on July 30, the company's president said Tuesday. Tom McGraw, Noridian's president and CEO, said the company "is cooperating fully as [the inspector general's] office continues its ongoing review" of the exchange.