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Stainless steels are a corrosion resistant family of iron alloys that have a minimum of 10.5% Chromium. Their corrosion resistance is largely due to the formation of a passive chromium (III) oxide (Cr2O3) layer, approximately 1 to 5 nanometers (nm) thick, on the surface of the steel. If this layer is damaged by cutting, scratching or abrasion, it will regenerate, provided sufficient oxygen is available. By contrast, Stainless steels have poor corrosion resistance in low oxygen environments since the oxide layer cannot be repaired quickly enough. In addition to chromium, Nickel, molybdenum and niobium are also alloyed to improve corrosion characteristics.

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Lead-based paints have been used extensively for painting the interior and exterior surfaces of homes. These paints were applied to almost any surface; however, they were most commonly found on interior and exterior woodwork including: doors, window frames and windowsills, cupboards and interior moldings. Almost all of the homes constructed before 1970 contain some lead-based paint. Until 1950, some of these paints contained up to 50% lead (500,000 ppm) and by the late 1960s, paints containing more than 1% (10,000 ppm) were still being used.

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