Sample of the element lead Pb in sheet form, rotating. Lead has the atomic number 82, and is a soft, dense post_transition metal. It is toxic, and overexposure can cause damage to the nervous system and the body in general. Uses of the metal and its compounds have decreased markedly since this toxicity was discovered, but it is still used in batteries, weights and bullets. Sheet lead such as this is used as a roofing material in the construction industry. It has one of the longest histories of use of any metal, and worked samples have been dated back to 6400 BCE.