An environmental hazard commonly found in ceilings, floors, and insulation is

Radon is a naturally occurring radioactive gas that can accumulate in buildings, particularly in basements and lower levels. While it is a significant indoor air quality hazard, it is not commonly found in ceilings, floors, or insulation materials. Its primary concern lies in its presence in enclosed spaces rather than in structural components.

Lead-based paint is primarily a hazard in homes built before 1978, where it may chip and create lead dust. Though it poses a risk, it is not typically found in ceilings, floors, or insulation as a structural component, but rather as a finish on walls and surfaces.

Carbon monoxide is a colorless, odorless gas produced by burning fossil fuels and can be hazardous when accumulated indoors. However, it is not a substance found in ceilings, floors, or insulation materials, making it irrelevant to the question of environmental hazards associated with building materials.