Polycylic Aromatic Hydrocarbons (PAHs) Polycyclic aromatic hydrocarbons (PAHs) are a class of chemicals that are formed in the incomplete burning of coal, oil, gas, or other organic matter. They can enter the air, water and adhere to particles in the soil. People are most likely to be exposed to PAHs by inhaling contaminated air. Workers at facilities that produce tar, asphalt, or incinerate trash are at the most risk; community exposure from vehicle exhaust, wood smoke, asphalt paving, or agricultural burning also occurs. Although less common, people can also be exposed by coming in contact with water contaminated with PAHs from discharges at wastewater treatment plants. The US Department of Health and Human Services classifies PAHs as “reasonably expected” to cause cancer. In animal studies, PAHs cause cancer, reproductive dysfunction, and birth defects. Asphalt shingles are roofing shingles that use asphalt for waterproofing. Because they’re inexpensive and easy to install they are the most widely used roofing covers in the United States, but the asphalt in them contains PAHs. In Wausau, Wisconsin, asphalt shingles waste has been buried as well as left in open-air piles. Case study: The grassroots community group Citizens for a Clean Wausau contacted The Center for Health, Environment & Justice (CHEJ) about the potential for these waste piles to leach PAHs into the air and soil, exposing surrounding residents. While much is unknown and the situation is ongoing, PAHs can leach out of asphalt at high temperatures and then be dispersed long distances by wind. This means Wausau residents may be inhaling PAHs, elevating their risk for developing cancer. To assess this possibility and the level of risk that may be posed to residents, measurements of contaminants in the shingles as well as in the surrounding air and dust would be necessary. The best way to ensure there is no risk to the community is to remove these shingles and destroy them safely. This PAH content is courtesy of "Toxic Tuesdays" at The Center for Health, Environment & Justice...