Lead is a naturally occurring element found in nature in the form of ores; it is a heavy, soft, malleable bluish metal. The history of it's use traces back many centuries. The oldest known lead object was a statue excavated in Turkey and dated somewhere around 6500 B.C. During the Roman Empire, lead was used extensively in many aspects of life; to line vessels that stored water and wine, in utensils, and, in combined form, as a glaze on pottery.

In more recent years lead was widely used to extend the protective properties of paints, helped automobiles attain better fuel efficiency, protected occupationally exposed workers from harmful radiation and provided a suitably dense material for ammunition, and fishing weights. Even though it is no longer used in many of these applications, millions of homes remain painted with lead paint. It's been estimated that approximately 94% of the residential housing in San Francisco was built prior to 1978 and probably has lead-based paint. Lead-based paint chips, as well as soil and household dust contaminated with lead are the primary sources of childhood lead poisoning.