Restriction on Coal Tar-Based Sealants

Coal tar-based sealant is widely used to recondition asphalt surfaces, but there are serious environmental concerns with its use.  The 2009 Legislature enacted a bill pertaining to use of coal tar-based asphalt sealants.  The bill restricts state agencies from purchasing undiluted coal tar-based sealant, and directs the Pollution Control Agency to study its environmental effects and develop management guidelines.

The  Legislation

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 will be implemented over the next two years as indicated below.

• Notify state and local government units
  By January 15, 2010 the MPCA must notify state agencies and local governments of the potential for contamination of stormwater ponds and wetlands by coal tar-based sealants.
• Inventory stormwater ponds
  The MPCA must complete a plan to inventory stormwater ponds in the state by January 15, 2010.
• State agencies restricted July 1, 2010
  State agencies may not purchase undiluted coal tar-based sealant after this date.
• Develop best management practices
  The MPCA must develop and make available best management practices that can avoid or mitigate environmental impacts of coal tar-based sealants.
• Develop model ordinance on use of sealants for local units of government (LUGs)
  available on this web site on or before January 2, 2010. 
• Develop grant process
  MPCA will develop a process by July 2010 for awarding grants to LUGs for treatment of contaminated sediment.  Ordinance must be in place to apply for a grant.  Watch this page for the RFP date (est. Sept. 2010) and application due date (est. Oct. 2010.)The bill contains other requirements for the MPCA but these are the ones of primary import for state and local governments and stormwater managers.
• Update: Grants to Help Manage PAH-Contaminated Stormwater Sediments
  Information about grant requirements and application materials is still under development and will be made available through this Web page on or before July 1, 2010. In the meantime, questions may be directed to Don Berger, 651-757-2223 or  This e-mail address is being protected from spambots. You need JavaScript enabled to view it.  

What Are The Concerns?

Coal tar, a byproduct of coal processing, contains high levels of chemicals called polycyclic aromatic hyrdrocarbons (PAHs).  Some PAHs are known human carcinogens.  It is commonly used in asphalt sealers.  Studies have shown when coal tar-based sealants are applied on parking lots and driveways, PAHs can be released into nearby surface waters, where they can accumulate to potentially harmful levels in sediments.  This also is a concern for local governments responsible for managing  stormwater ponds and disposing of sediments dredged from them.  Alternatives to coal tar-based sealer formulations are available that have far lower levels of PAHs.

This MPCA fact sheet provides more information on the environmental concerns related to coal tar-based sealant.

MS4 Permittees

By the next cycle of municipal stormwater permitting, permittees will be required to abide by all provisions of the legislation. 

NOTE: the MPCA recommends that permittees suspend conducting additional work on their stormwater pond inventory (beyond what you may currently have under contract), until the pond inventory guidance below is updated to reflect revised pond inventory requirements in the reissued MS4 General Permit. The schedule for the pond inventory requirements will be based on the issuance date of the next MS4 General Permit, expected in late summer 2012.

•  MS4 Stormwater Pond Inventory Form: (wq-strm4-30) 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 other water bodies impacted by the collection, treatment and conveyance of stormwater.
• MS4 Stormwater Pond Inventory Guidance (wq-strm4-31) (see note above)
• Model ordinance:  The MPCA and League of Minnesota Cities developed a model ordinance for use by cities that may wish to restrict the use of coal tar-based sealants.

MPCA Contact

For more information on PAH contaminated dredge material from stormwater best management practices, contact Chris Buntjer at 651-757-2252 or This e-mail address is being protected from spambots. You need JavaScript enabled to view it. . For more information on prevention, contact Don Berger at 651-757-2223 or This e-mail address is being protected from spambots. You need JavaScript enabled to view it. .

Links to Other Information

• Summary of Coal Tar-based Sealant Bans/Restrictions in the United States 2011. Minnesota Pollution Control Agency, St. Paul, MN. (tdr-g1-12)
• Coal-Tar-Based Pavement Sealcoat, Polycyclic Aromatic Hydrocarbons (PAHs), and Environmental Health, USGS Fact Sheet 2011
• Contamination of Stormwater Pond Sediments by PAHs in Minnesota. 2010. Minnesota Pollution Control Agency, St. Paul, MN.
• Symposium on "PAHs in Our Environment – Their Science and Regulation" given November 18, 2011 in Groton, CT. Sponsored by the Institute of Environmental Stewardship, LLC, University of Connecticut, and Sea Grant Connecticut.
• Thinking about Sealcoating your Driveway? Fact Sheet, University of New Hampshire Stormwater Center, 2011
• Assessment of Water Quality in Runoff from Sealed Asphalt Surfaces (EPA)
• Contamination of Stormwater Pond Sediments by Polycyclic Aromatic Hydrocarbons
• USGS Fact Sheet 
• Pavement Sealer Applications technical guidance. Washington State Department of Transportation.
• Characterization of Stormwater Pond Sediments. Final project report.  Metropolitan Council Environmental Services, St. Paul, MN.
• Managing Dredged Materials in the State of Minnesota.  2009. Minnesota Pollution Control Agency, St. Paul, MN.