Lead Paint or Lead-Based Paint is any paint or surface coating that contains more than .5% lead by weight or 5000ppm. It was commonly used as a pigment in paint manufactured before 1978. It made the paint more durable, weather resistant, abrasion resistant, flexible and the colors vibrant.
Lead Paint was banned from household paint in 1978 but is can still be used for industrial applications like bridges, marine applications like cargo and container ships, and even as road stripes on highway, road and parking lots.
25 to 38 million homes in the US are estimated to contain lead paint on at least one surface.