Coal tar is a known human carcinogen (USGS 2015). PAHs from coal-tar-based sealcoat can contaminate house dust, a particular risk for small children, who spend time on the floor and put their hands and objects into their mouths. Although unseen, releases of PAHs to the atmosphere (volatilization) from freshly coal-tar-sealed pavement are tens of thousands of times higher than from unsealed pavement. This is a potential human-health concern because inhalation is an important pathway for human exposure to PAHs. Runoff from coal-tar-sealcoated pavement is also acutely toxic to aquatic life. Dust on coal-tar-sealed parking lots contains bits of abraded sealcoat particles, and PAH-contaminated dust that is not trapped by stormwater management devices can be transported to streams and lakes, where it settles.