What are the concerns?
The Minnesota Legislature banned the sale and use of coal tar-based sealants on January 1, 2014. These products were commonly applied to asphalt driveways, parking lots and some recreational trails to protect the underlying asphalt. However, these sealants contain high concentrations of chemicals called polycyclic aromatic hydrocarbons (PAHs), and environmental mixtures of PAHs are generally carcinogenic. At high enough exposures, environmental mixtures of PAHs may cause cancer.
PAHs are ubiquitous in the environment, so it’s recommended that people should limit their exposure to concentrated mixtures of PAHs. PAHs in coal tar-based sealants are released into the environment through volatilization into the air and as dust when the sealant breaks up over time. This dust can be tracked into homes or transported to nearby soils and waters via stormwater runoff. An MPCA study found that about 67% of total PAHs in the sediments of 15 metro-area stormwater ponds were from coal tar-based sealants. In some cases, high concentrations of PAHs have accumulated in stormwater ponds.
This is a concern for local governments responsible for managing stormwater ponds and disposing of sediments that have been excavated from them. Alternatives to coal tar-based sealants, such as asphalt-based sealants, are available that have far lower levels of PAHs.
The new law
Coal tar-based sealant is widely used to recondition asphalt surfaces, but there are serious environmental concerns with its use. Minnesota passed a law during the 2013 legislative session which bans the use and sale of coal tar-based sealcoats effective January 1, 2014. Coal tar-based sealants can no longer be sold or applied legally in Minnesota. The new law will help minimize the ongoing release of harmful and persistent chemicals that can harm our lakes and rivers and will also help minimize clean-up costs to taxpayers.
To learn more about coal-tar based seal coats, safer alternatives, or frequently asked questions please visit our Coal Tar-Based Sealcoat webpage or the information about Moving to safer alternatives to coal tar sealcoats webpage. Questions about safer alternatives or assistance to retailers, suppliers, commercial applicators, contractors and business associations about disposal of unused retail or commercial stocks may be directed to Al Innes, at 651-757-2457 or firstname.lastname@example.org
Sediment removal guidance and video on sediment removal
- Managing Stormwater Sediment Best Management Practice Guidance (wq-strm4-16)
- Summary of Stormwater Pond Sediment Testing Results (wq-strm4-79)
- Hydraulic dredging for removal of stormwater pond sediments
A short video highlighting key topics for sediment removal projects supplements the guidance document and provides a few visual examples associated with the removal of sediment from stormwater collection and conveyance systems. These guidance documents do not provide a comprehensive list of everything that should be considered when managing a sediment removal project, but they can help highlight important steps to be taken by those responsible for performing a sediment removal project.
Questions about operation and maintenance of stormwater collection and conveyance systems, sediment removal projects, or guidance about best management practices contact Don Berger, at 651-276-7235 or Donald.email@example.com.
More information about coal tar-related legislation in Minnesota or information about the phase-out of coal tar-based sealers in the Great Lakes region can be found below in the link to Background information.
The 2009 Legislature enacted a bill pertaining to the use of coal tar-based asphalt sealants. The bill restricted state agencies from purchasing undiluted coal tar-based sealant, directed the MPCA to develop a model ordinance for cities considering local restrictions on coal tar-based sealants, and directed the MPCA to study its environmental effects and develop management guidelines.
The MPCA and League of Minnesota Cities developed a model ordinance for cities that wish to restrict the use of coal tar-based sealants: Model coal tar ordinance (LMC).
The 2009 legislation was contained in House File 1231. References to coal tar-based sealants are in Article 2, Sections 4, 26 and 28. The main requirements outlined in the legislation have been implemented in the years since the bill was enacted.
- Notify state and local government units of the potential for contamination of stormwater ponds and wetlands by coal tar-based sealants
Completed January 2010.
- Inventory stormwater ponds
The MPCA must incorporate requirements to inventory stormwater ponds into the next permitting cycle for MS4 communities This requirement (contained in Appendix A, Table 2 of the 2013 Reissuance of the General NPDES/SDS Permit MNR040000 for MS4s). This inventory is required by Chapter 172, Sec. 28 of the 2009 Session Laws. The purpose of the inventory is to identify stormwater ponds, wetlands and lakes impacted by the collection, treatment and conveyance of stormwater. Completed 2013.
- State agency purchases of undiluted coal tar-based sealant restricted July 1, 2010
Implemented in 2010.
- Develop best management practices that can avoid or mitigate environmental impacts of coal tar-based sealants
Completed June 2012; see Managing Stormwater Sediment Best Management Practice Guidance for Municipalities
- Develop model ordinance on use of sealants for local units of government (LUGs)
Completed January 2010.
- Develop process and award sediment clean-up grants to cities enacting a ban ordinance
All funds have been exhausted as of September 2012. Questions may be directed to Don Berger, 651-276-7235 or Donald.Berger@state.mn.us.
Changes have been made to the guidance provided for stormwater sediment best management practices. These changes include:
- A permit is not required when performing routine maintenance on a stormwater conveyance and collection system.
- The MPCA no longer needs to be notified of the sediment removal activity using the “Stormwater Facility Dredge Report Form”. Municipalities and other MS4’s are advised to keep their own records of sediment removal projects, and
- The guidance includes best management practices summarized by cities for cities including topics beyond just regulatory concerns.
The MPCA grant funds to assist municipalities with removing contaminated sediment from stormwater ponds were exhausted as of September 2012.
Municipalities were eligible for grant money if they first established an ordinance restricting the use of coal tar-based sealants in their jurisdiction. The following cities received grant money to assist with the proper disposal of contaminated sediment from their stormwater ponds once they established an ordinance restricting the use of coal tar-based sealants:
- Circle Pines
- Golden Valley
- Inver Grove Heights
- White Bear Lake
Great Lakes Restoration Initiative
In 2011, the, MPCA was awarded a grant from U.S. EPA’s Great Lakes Restoration Initiative to promote the phase-out of coal tar-based sealants in Minnesota and in partnering Great Lakes states through 2014. Information on this grant project and continuing activity is available on the Great Lakes Coal Tar Sealcoat PAH Reduction Project webpage or by contacting Al Innes, at 651-757-2457.
In the years following the 2009 legislation, cities in Minnesota and across the U.S. passed local bans on coal tar-based sealants. A list of cities with bans, plus other jurisdictions and academic institutions with restrictions is in the following fact sheet — Summary of Coal Tar-based Sealant Bans/Restrictions in the U.S.
Frequently Asked Questions
Municipalities and others responsible for the operation and maintenance of stormwater collection and conveyance systems often contact the MPCA for more information about PAHs, coal tar-based sealers and managing contaminated sediments. See the FAQs and answers page for assistance.
Links to other information
- Coal-Tar Sealcoat, Polycyclic Aromatic Hydrocarbons, and Stormwater Pollution (U.S. EPA)
- Use of Compost to Biodegrade Sediments Contaminated with Polycyclic Aromatic Hydrocarbons
- Summary of Coal Tar-based Sealant Bans/Restrictions in the United States
- EPA's Stormwater Pollution Prevention Webinar Series - Stormwater, Coal-Tar Sealcoat, and Polycyclic Aromatic Hydrocarbons (PAHs)
- Parking Lot Sealcoat - A Major Source of Polycyclic Aromatic Hydrocarbons (PAHs) in Urban and Suburban Environments (2006)
- Contamination of Stormwater Pond Sediments by Polycyclic Aromatic Hydrocarbons
- Pavement Sealcoat a Source of Toxins in Stormwater Runoff
- Assessment of Water Quality of Runoff from Sealed Asphalt Surfaces (U.S. EPA)
- Coal-tar-based Pavement Sealcoat, Polycyclic Aromatic Hydrocarbons (PAHs), and Environmental Health
- Coal-Tar-Based Pavement Sealcoat and PAHs - Implications for the Environment, Human Health, and Stormwater Management
An overview of how PAHs from coal-tar-based sealant are contaminating the environment, including stormwater ponds. Information on environmental and human health concerns associated with these pollutants is also included. (Journal of Environmental Science and Technology, January 2012)
- Urban waterways - Polycyclic Aromatic Hydrocarbons (PAHs) in urban waters
NOTE: the MS4 Pond, Wetland and Lake Inventory form must be submitted within 12 months of the date permit coverage is extended, as found in Appendix A, Table 2 of the 2013 Reissuance of the General NPDES/SDS Permit MNR040000 for Municipal Separate Storm Sewer Systems (MS4s).
- MS4 Pond, Wetland and Lake Inventory Form This inventory is required by Chapter 172, Sec. 28 of the 2009 Session Laws. The purpose of the inventory is to identify stormwater ponds, wetlands and lakes impacted by the collection, treatment and conveyance of stormwater.