The steel scrap-EAF route of steelmaking requires substantially lower primary energy consumption (70kg in terms of carbon) and associated CO2 evolution than the Iron ore-BF-BOF route (440kg in terms of carbon) to produce one metric ton of steel. This substantial difference is attributed to the considerable energy required to reduce iron ore into iron in the latter route. For the time being, perhaps even in the very near future, no technologically effective means will be made available to stabilize evolved CO2 and prevent the CO2 accumulation in the atmosphere. Measures to be taken are, therefore, the reduction of CO2 evolution (reduction of fossil fuel consumption) for the sustainable development. Recycling of steel scrap considerably contributes to this goal. Accordingly, energy and environmental issues encourage the use of the scrap-EAF route. So far, the scrap-EAF route has been used mainly to produce either long products (shapes, bars, rods and wires) of commodity grades in large quantity from obsolete and prompt industrial scrap or the same and forgings of high quality grades mostly from home-and/or prompt industrial scrap. In recent years, however, the new thin slab casting technology has enabled scrap-EAF steelmakers to produce flat products. Thin slab casting technology was pioneered by SMS, Germany, in the Compact Strip Process (CSP), and reached operational maturation at Nucor Steel Inc., USA. Similar processes have subsequently been developed, including the In-line Strip Process (ISP) of Demag/Arvedi. Thin slabs are cast into either a funnel shaped taper mold or straight taper mold 60-100mm in thickness at the outlet, subject to reduction to about 50mm in thickness during strand withdrawal while they still retain a liquid core, and reduced in-line to about 30mm in thickness followed by hot rolling with tandem hot strip mill consisting of a smaller number of roll stands. An integrated line comprising an advanced EAF-thin slab caster can produce up to about 1 million ton/year with much lower investment in facilities and much less energy consumption. The typical composition of such mills is shown schematically in this figure. There has also been considerable progress in improving the efficiency and productivity of EAFs, including preheating of scrap, continuous feeding of scrap, twin shell furnaces, and a variety of DC-Arc furnaces. Combined with such EAFs, technology has made it possible to eliminate roughing mills and to carry out in-line rolling at an attractive investment wherever scrap is available. As the thickness of the slabs is about 30-50% that of conventional continuously cast slabs, the casting speed should be two to three times higher, or about 6m per minute for a thin slab caster with 1 million ton /year of production. In such high speed casting, some steels sensitive to cracking tend to suffer surface degradation and in an extreme case of medium carbon peritectic steels, casting cannot yet be performed due to deterioration of slab surfaces by crack formation. This difficulty should be overcome by further development of the process. In view of the increasing generation of scrap in the industrialized countries, the scrap-EAF-thin slab caster combination will gain an increasing share in world steel production. Qualitywise, these steelmakers have concentrated on the commodity grades, but now are upgrading to high quality products, including deep drawing steels. Obvious limitations for the upgrading are, however, that the scrap-EAF route should not cause either deterioration of the properties of the resulting steels due to residuals such as Cu, Sn, As, Sb, Bi, or associated pollution from accompanying volatile residuals such as Zn and Pb and waste such as some plastics, which generate harmful dioxines.