Steel is amongst the most widely utilised materials in modern society and has an important role to play in sustainable development. Steel has a number of environmental impacts which, in some cases, can be significant. Equally, steel is used safely and effectively in all aspects of modern life and has had a pivotal role in human technological development. Balancing the positive and negative aspects of steel are fundamental to achieving sustainable development. This note provides information on the environmental and sustainability impacts of steel and is intended to assist building design professionals in using steel more sustainably. The production of steel and it's most significant environmental effects are discussed in the context of sustainable development.