On November 14, 2011, the City Council approved an ordinance prohibiting the use of coal tar-based driveway sealers. Some of the chemicals (called polycyclic aromatic hydrocarbons, or PAHs) are known to cause cancer in people and fish, and to harm the aquatic food chain. In addition to the potential health risk of PAHs, there can be substantial costs for cities and private property owners to manage sediment in storm water ponds that are contaminated with PAHs from coal tar-based sealants. The MPCA keeps a list of Contractors who have pledged not use coal tar-based sealers. Asphalt-based sealers are an acceptable alternative. Click on this link to access the list of contractors.