A fashion bill pending in Congress could dramatically increase apparel lawyers’ work — and make it a lot harder for consumers to stay in style.

The Design Piracy Prohibition Act, S.B. 1957, would allow designers to copyright their designs — and not just their logos — for three years. That could lead to a flood of litigation as designers move to sue retailers who sell knock-offs intended for the mass market. And even as they acknowledge the potential business windfall, some L.A. fashion lawyers feel so strongly about the bill they’re joining an effort to stop its passage.