Final answer:
Federal law specifically mandates written disclosure for lead-based paint due to its considerable health risks and prevalence in older homes. While other substances like radon and formaldehyde are recognized as health risks, the requirement for written disclosure at the time of the home sale is unique to lead-based paint.
Step-by-step explanation:
Federal law requires written disclosure to be provided to purchasers for certain environmental hazards when buying a house. Among these, lead-based paint is a significant concern, and disclosure is indeed mandated. Lead-based paint was banned in 1978; however, many homes built before that still contain it. This is of particular relevance as deteriorating paint can expose residents to lead dust, leading to various health problems, especially in children.
For this reason, property sellers must disclose the presence of lead-based paint. While other hazards such as formaldehyde, asbestos, and radon are also health concerns, the explicit requirement for written disclosure at the time of sale is specifically emphasized for lead-based paint due to its widespread historical use and significant health impacts.