Lead is a basic element. It is found in mines in Missouri, Alaska, Colorado, Idaho, Montana and Canada. For these reasons it is found in far more industries and exposures than most people realize. The contamination is believed to be in homes, including in airborne dust. It can also be in soil, including farm land, and even in the food chain.
Airborne dust is part of normal daily life.
Lead is in the dust in homes if lead paint was used on the walls, etc. Another area of exposure is dust from the removal process on bridges and industrial buildings. Soil contamination can come from leaded gasoline products, former gas station sites, and, again, the removal process from the exterior of industrial buildings and bridges. Large bridges are being stripped and painted continuously, each time adding to the lead contamination in the area. In many occupations involving exposure to lead, OSHA and other regulatory requirements provide protection from over-exposure.