Scrap metal shredders can be equipped with different types of cutting systems: horizontal shaft, vertical shaft, single-shaft, two-shaft, three-shaft and four-shaft cutting systems. These shredder designs can be high speed, medium speed and sometimes slow-speed systems, they always include hammermills of a vertical and horizontal shaft design, and can also include in contrast to hammer mills slow speed technology which are also used to process or shred metal and plastic and other waste materials encountered in the scrap metal industry. The largest scrap metal shredders in the world often have 10,000
horsepower (hp) and are made by a wide range of companies. The designs originate from the 1966 patent applications of the Newell Group and the Williams Group for auto shredding or scrap metal shredding. One example is the 9,200 hp shredder from the Lynxs group at the Sims plant at the mouth of the
River Usk in Newport
Wales. This Lynxs shredder can process 450 cars per hour. However, the Lynxs shredders are not unique in this high hp range design. The Schnitzer Steel group installed their own custom made 10,000 hp unit in 1980, and there are many Newell Shredders that have these high hp designs. A 9,000 horsepower Mega Shredder at Sims Metal Management's Claremont Terminal in Jersey City, New Jersey processes 4,000 tons of metal a day. == Impacts on humans and environment ==