Maryland’s labor unions are strongly backing approval for the slot machine referendum on the November ballot, they announced Friday. They said it represents a chance to bolster finances for education and other important programs they support and an opportunity to create good union jobs at the slots locations.“Passage of the slots referendum will be a fiscal win for the state of Maryland,” said Fred Mason, president of the Maryland and DC AFL-CIO. He said the political committee “will be mobilizing our members,” which includes 300,000 members in 500 unions. One in four households in Maryland has a union worker, he said. “They understand that much revenue is going to neighboring states.”