The sealants have been used for decades to keep pavement from cracking, but they contain high levels of toxic compounds called polycyclic aromatic hydrocarbons. PAHs are a concern because they're toxic to fish and other aquatic life. Several are probable human carcinogens.
A recent study by the U.S. Geological Survey found that coal tar sealants have contaminated 40 urban lakes, including Lake Washington and Lake Ballinger in Mountlake Terrace.
Representative David Frockt of Seattle says safer alternatives are available. Anne LeHuray with the sealant industry says a statewide ban would hurt small businesses.