The leading US autoworkers union charged Friday that a "firestorm" of interferenece from politicians and outside special interest groups affected a vote on union representation last week at a Volkswagen auto plant in Tennessee, according to dpa. Workers at the factory in Chattanooga voted 712-626 against representation by the United Auto Workers union (UAW) based on a model common in German industry. The UAW on Friday filed a complaint with the National Labor Relations Board (NLRB) saying politicians and "politically motivated third parties" put out a message prior to the vote that the economic future of the plant would be threatened by a move to unionize.