This method, however, did not protect human health or the environment from harmful chemicals, nor did it salvage valuable parts and materials from these vehicles. Fluids leaked from the vehicles onto the ground, contaminating soils and ground water, while valuable metals and parts rusted away.

Today, end-of-life vehicle management practices attempt to minimize environmental impacts and to recycle vehicle materials through a network of vehicle salvage and shredder facilities. Through this network, fluids can be drained and properly collected, usable components can be salvaged, and recyclable materials (primarily metals) can be separated and recycled. These processes result in approximately 25 percent of vehicles being recycled, by volume, after shredding (75 percent by weight). In the United States, there are approximately 12,000 salvage facilities and 182 shredders that process end-of-life vehicles. Each year, this network processes approximately 10 million vehicles, generating more than 450 million cubic feet of auto shredder residue (ASR) that must be properly disposed of.

Interestingly enough, although vehicle shredding may efficiently separate metals from nonmetals, and ferrous (iron-containing) from nonferrous metals, it does not preserve the greatest material value. The most notable loss is in the "ASR waste stream" – a mixture of plastics and other recyclable materials that have been ground together so that the individual materials no longer have any commercial value. Additionally, metals are generally contaminated; for example, coatings such as paints and plated metals, and trace metals from the shredding process contaminate the metals separated from the rest of the vehicle. These contaminants both make the recycling process more difficult and may limit the applications for which the recycled material can be used.

Although recycling is one way to reduce the consumption of natural resources and the generation of waste, it is energy intensive and produces its own wastes and pollutants. Therefore, in order to address these issues, vehicle manufacturers should be encouraged to use fewer materials to achieve the same performance standards and substantially reduce life-cycle (particularly end-of-life) impacts.


Salvage Facilities
Vehicle salvage facilities, also known as "dismantlers," usually are the first places that receive vehicles after their useful life. Workers at the facility dismantle the vehicle, salvage usable parts, and crush the remaining vehicle "hulks" to allow further processing by the vehicle shredders.

After an initial inspection, salvage facility workers begin to dismantle vehicles by draining and collecting all fluids, such as fuel, various oils and lubricants, coolants and antifreeze, window-washing fluids, refrigerants, steering fluids, and brake fluids. These fluids should be collected separately to minimize cross-contamination and make it easier to recycle them.

Once drained, those vehicle parts that can be reused are removed. These parts may have resale value as used or refurbished after-market parts (e.g., radiators, engines, small motors for power windows, some electronics, alternators, and tires); other parts may have material value (e.g., lead in batteries or precious metals from catalytic converters). These parts are removed from the vehicles, collected, and sold.

What remains after all parts of value are removed from a vehicle is called the "hulk" – the metal components of the vehicle body, some electronics, and most of the plastics (e.g., seats, dash board, fabric), glass, and rubber. This hulk can be crushed by the salvage facilities (optional) and sold to vehicle shredders for materials recycling.


Vehicle Shredders
Vehicle shredders perform two primary tasks – shredding and separation. The shredding process chops the vehicle hulks received from the salvage facilities into small pieces no bigger than a fist. Once shredded, the pieces are separated according to the materials from which they are made.

Most of a vehicle's iron and steel is removed magnetically. While the shredded material passes under a powerful magnet, these metals stick to the magnet, while all the other materials continue on to other separation processes. The materials remaining after magnetic separation then are further separated through a variety of processes. For example, these materials may be washed in water, during which the heavy pieces sink to the bottom of the water bath, while light objects, such as plastics, float. The materials that sink are separated again into various metals (e.g., copper or aluminum, using eddy current or centrifugal separation), glass, and heavy rubber and plastic materials.

As many metals as possible are recycled. Iron and steel, aluminum, and other metals represent the 75 percent of the vehicle weight that is typically recycled. The materials that remain – plastics, rubber and glass – are called "fluff" or automotive shredder residue (ASR), and represent a massive waste stream generated by vehicle shredders and the automotive industry in general. About 4.5 million to 5.0 million tons of ASR, or 450 million to 500 million cubic feet, are generated each year in the United States and must be disposed of in landfills or incinerated.