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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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