Which substance has been eliminated from use in residential building construction due to health hazards?

Lead has been heavily regulated and largely eliminated from residential building construction due to its severe health hazards, particularly concerning lead poisoning. Lead exposure can occur from lead-based paints, plumbing systems, and various other sources used in construction prior to regulations that were implemented in the late 20th century. Specific health risks include developmental issues in children, neurological damage, and various other serious health conditions.

As regulations have increased, especially following the Environmental Protection Agency (EPA) guidelines and the Lead Renovation, Repair and Painting (RRP) Rule, it has become mandatory to handle and remediate lead-containing materials appropriately in residential properties, effectively removing its widespread use in new construction. While asbestos and formaldehyde also present significant health risks and have seen restrictions in their use, the context of dangerous materials in residential buildings highlights lead as a primary concern due to its historically prevalent use and the long-term health impacts associated with it. Mold is more of a biological concern than a building material and does not fit the same criteria as the others listed, which are all materials that have been used in construction.