QUICK FACTS

Vapors in soil gas from contaminated soil and groundwater enter buildings through cracks in the foundation and openings for utility lines. Atmospheric conditions and building ventilation are shown to influence soil gas intrusion. 

Vapor intrusion is the general term given to migration of hazardous vapors (e.g., petroleum hydrocarbons and chlorinated solvents) from any subsurface vapor source, such as contaminated soil or groundwater, through the soil and into an overlying building or structure. These vapors can enter buildings through cracks in basements and foundations, as well as through other conduits/openings (e.g., sewers, drain lines). All types of buildings, regardless of foundation type (e.g., basement, crawl space, slab-on-grade), have openings that render them potentially vulnerable to vapor intrusion. 

Septic systems are designed for waste that bacteria can break down quickly and easily. This does not include most chemicals. Flushing or discharging hazardous chemicals simply relocates them under your lawn then surface water. Any household cleaning products, chemicals, or medicines that you flush down the toilet could end up in surface water, so don’t use your toilet as a trashcan. Chemicals discharged into septic systems can negatively impact water quality and public health in both groundwater and surface water sources, even in very small amounts. Contact your local hazardous waste disposal facility to ask about how to correctly dispose of these materials.