Final answer:
Real estate regulations require the disclosure of lead-based paint in residences to new purchasers and tenants due to its health risks.
Step-by-step explanation:
Regulations require that real estate agents and property owners must disclose to purchasers and new tenants if the residence contains lead-based paint. This requirement is based on the documented health risks of lead exposure. Lead-based paint was commonly used in homes prior to its ban in 1978. When it deteriorates or is disturbed during home renovations, it poses a significant health risk. The U.S. government, specifically the Environmental Protection Agency (EPA), has set regulations to ensure individuals are informed about the presence of lead-based paint to avoid potential health problems.
Other chemical pollutants such as radon, a naturally occurring radioactive gas, can also become trapped inside buildings and is known to increase the risk of lung cancer. However, the specific regulatory requirement for disclosure cited in the question pertains to lead-based paint.