Also see Reporting Demolition Hazards
1. The “Legacy” Toxins (Pre-1980s Materials)
Older structures frequently harbor materials that were standard industry practice for decades before being restricted or banned.
- Asbestos: Still the most critical hazard during demolition. It is found in pipe insulation, vinyl floor tiles, popcorn ceilings, roofing shingles, and siding. When disturbed, microscopic asbestos fibers become airborne, posing severe risks of lung cancer and mesothelioma if inhaled.
- Lead: Primarily found in lead-based paint (common in pre-1978 residential buildings). Demolition crushes this paint into fine, toxic dust. Lead is also found in older plumbing pipes, solder, and roof flashing.
- Polychlorinated Biphenyls (PCBs): Highly toxic, man-made chemicals widely used in construction between 1950 and 1979. In demolition debris, they are typically found in old fluorescent light ballasts, window caulk, joint sealants, and electrical transformers.
2. Heavy Metals
Crushing and tearing apart building infrastructure releases heavy metals into the air or allows them to leach into surrounding soil and water table systems.
- Mercury: Commonly found in older thermostats, silent light switches, and fluorescent light tubes.
- Arsenic & Chromium: Heavily concentrated in CCA-treated wood (Chromated Copper Arsenate). While banned for residential use in 2004, it is still frequently present in older outdoor decks, playsets, fences, and utility poles. Burning this wood or chipping it releases highly toxic arsenic dust and smoke.
- Cadmium & Beryllium: Frequently found in electronic waste (e-waste) left in buildings, industrial equipment, and certain rust-resistant metal coatings or batteries.
3. Hazardous Dusts & Synthetic Fibers
Mechanical demolition pulverizes structural elements into airborne particles that pose direct respiratory hazards.
- Crystalline Silica: Found in concrete, brick, mortar, tile, and stone. Grinding, cutting, or crushing these materials releases respirable silica dust, which causes silicosis (irreversible lung scarring) and increases lung cancer risk.
- Synthetic Mineral Fibers (SMF): This category includes glass wool (fiberglass), rock wool, and ceramic fibers used for thermal and acoustic insulation. They can cause severe skin, eye, and upper respiratory tract irritation during handling.
4. Modern Chemical Residues & Halocarbons
- Ozone-Depleting Substances (ODS): Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are present in the refrigerants of older commercial and residential air conditioners, refrigerators, and some rigid foam insulation boards.
- Volatile Organic Compounds (VOCs): Found in remnants of old solvents, industrial adhesives, chemical wood stains, and oil-based varnishes left behind in structures.
A Note on Landfill Risks: When these materials are dumped together, the presence of gypsum plasterboard (calcium sulfate) complicates things. In wet landfill conditions, gypsum breaks down to produce highly toxic, foul-smelling hydrogen sulfide () gas, which also lowers pH levels and makes it easier for heavy metals like lead and arsenic to leach into local groundwater.