Which part of a home built before 1978 would be the least likely to contain lead?

The least likely part of a home built before 1978 to contain lead is the sheetrock (wallboard). During the time when many homes were constructed before the ban on lead-based paints in 1978, lead was primarily found in paint, particularly on surfaces that were frequently painted, such as walls and trims, and in some cases, even in the soil surrounding the home.

Sheetrock, on the other hand, is made from a gypsum core sandwiched between two sheets of heavy paper or fiberglass matting. The materials used to manufacture sheetrock typically did not contain lead. The concern regarding lead in homes primarily centers around lead-based paint and, to a lesser extent, lead found in plumbing systems, particularly in solder used in pipes.

Areas like outside dirt can also be contaminated due to lead from deteriorating lead-based paint or other environmental sources, which further supports that sheetrock is the least likely to contain lead.