Pressed wood products like particleboard, plywood, and MDF are major formaldehyde sources, along with glues and adhesives used throughout construction. Insulation materials, particularly urea-formaldehyde foam insulation, continue off-gassing for years after installation. Textiles including wrinkle-resistant fabrics, cleaning agents, disinfectants, and combustion byproducts from gas stoves and fireplaces add to contamination. The Lumber Liquidators scandal revealed that imported flooring can contain formaldehyde levels up to 20 times the safe limit, and this problem extends beyond one retailer to many imported products. Property managers need professional testing to identify contamination sources and protect building occupants.