With the increase in household products containing pollutants and the decrease in the quality of building ventilation, indoor air has become a significant source of pollutant exposure. Residents living in homes with wood floors treated in the 1960s with PCB-based wood finish have a much higher body burden than the general population. A study of indoor house dust and dryer lint of 16 homes found high levels of all 22 different PBDE congeners tested for in all samples. Recent studies suggest that contaminated house dust, not food, may be the major source of PBDE in our bodies. One study estimated that ingestion of house dust accounts for up to 82% of our PBDE body burden.