Complex sentence: They faced difficult work conditions, including unpredictable hours, poor ventilation, and a low wage piece work system, in which they were paid for each garment produced instead of by the hour even though such systems often violated living wage laws in Los Angeles.
Split into simpler sentences: They faced difficult work conditions, including unpredictable hours, poor ventilation, and a low wage piece work system. In a piece work system, they were paid for each garment produced instead of by the hour even though such systems often violated living wage laws in Los Angeles.