Our town centres were often originally residential areas that contained small cottages that were filled with lead including plumbing, roof flashings, lead head nails, lead paint and paint with arsenic, cadmium and chromium based dyes. These early dwellings often went through a transitional industrial use prior to their demolition in the mid to late 1800s, both of which commonly resulted in significant contamination of the site. This early occupation layer is the most widespread source of contamination of urban land.