titanium, tungsten, arsenic, beryllium, bismuth, cerium, cadmium, niobium, indium, gallium, germanium, lithium, selenium, tantalum, tellurium, vanadium, and zirconium. Some types of metals are radioactive. These may be "naturally occurring" or formed by nuclear reactions. Metals that have been exposed to radioactive sources may also become radioactive in settings such as medical environments, research laboratories, and nuclear power plants. OSHA guidelines should be followed when recycling any type of scrap metal to ensure safety. Ferrous metal recycling Ferrous metals are able to be recycled, with steel being one of the most recycled materials in the world. Ferrous metals contain an appreciable percentage of iron and the addition of carbon and other substances creates steel. Description In the United States, steel containers, cans, automobiles, appliances, and construction materials contribute the greatest weight of recycled materials. For example, in 2008, more than 97% of structural steel and 106% of automobiles were recycled, comparing the current steel consumption for each industry with the amount of recycled steel being produced (the late 2000s recession and the associated sharp decline in automobile production in the US explains the over-100% calculation). A typical appliance is about 75% steel by weight and automobiles are about 65% steel and iron. The steel industry has been actively recycling for more than 150 years, in large part because it is economically advantageous to do so. It is cheaper to recycle steel than to mine iron ore and manipulate it through the production process to form new steel. Steel does not lose any of its inherent physical properties during the recycling process, and has drastically reduced energy and material requirements compared with refinement from iron ore. The energy saved by recycling reduces the annual energy consumption of the industry by about 75%, which is enough to power eighteen million homes for one year. According to the International Resource Panel's Metal Stocks in Society report, the per capita stock of steel in use in Australia, Canada, the European Union EU15, Norway, Switzerland, Japan, New Zealand, and the US combined is (about 860 million people in 2005). Basic oxygen steelmaking (BOS) uses 25–35% recycled steel to make new steel. BOS steel usually contains lower concentrations of residual elements such as copper, nickel, and molybdenum, and is, therefore more malleable than electric arc furnace (EAF) steel, and is often used to make automotive fenders, tin cans, industrial drums, or any product with a large degree