Final answer:
If a building was constructed before 1978, the Lead Paint Disclosure Form must be used to inform potential buyers or renters about the possible presence of lead-based paint.
Step-by-step explanation:
If a building was constructed before 1978, the Lead Paint Disclosure Form must be used. This is because lead-based paint was banned by the U.S. government for use in housing in 1978. However, many older homes still have lead paint underneath newer layers. The form is used to inform potential buyers or renters about the possible presence of lead-based paint in the building.