Labor groups have accused a Winslow-based aluminum trailer manufacturer of illegally firing employees for trying to unionize. Matt Schlobohm, executive director of the Maine AFL-CIO, says five employees at Alcom Inc. have been fired this month in connection with efforts to form a union to negotiate better pay, benefits and working conditions. Schlobohm said the firings violate the federal National Labor Relations Act, under which it is illegal to retaliate against employees seeking to unionize. Alcom President Trapper Clark denies the accusations. He tells the Kennebec Journal, he supports the right of workers to unionize and no one has been fired for exercising that right. He called the allegations “false” and “extremely unfortunate.” He says the company just improved health insurance options. The company has 185 workers in Maine.