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, directs the MPCA to develop a model ordinance for cities considering local restrictions on coal tar-based sealants, and directs the MPCA to study its environmental effects and develop management guidelines.

In 2011, MPCA was awarded a grant from U.S. EPA’s Great Lakes Restoration Initiative to promote the phase-out of coal tar-based seal coats in Minnesota and in partnering Great Lakes states through 2014. Information on this grant project is available on the Moving to safer alternatives to coal tar sealcoats webpage or by contacting Al Innes, at 651-757-2457 or alister.innes@state.mn.us.

City restrictions

In the years since the 2009 legislation, several Minnesota cities have passed local bans on coal tar-based sealants. A list of those cities based on the most recently-available information is available on the following fact sheet: Summary of Coal Tar-based Sealant Bans/Restrictions in the United States (tdr-g1-12)

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. Model ordinance (wq-strm4-82)

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 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 (expected late 2012).
• State agencies’ purchase of undiluted coal tar-based sealant restricted July 1, 2010
  Implemented.
• 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 (wq-strm4-16)
• 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, 651-757-2223 or Donald.Berger@state.mn.us.

Changes have been made to the guidance provided for stormwater sediment best management practices.  These changes include:

1. A permit is not required when performing routine maintenance on a stormwater conveyance and collection system.
2. 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
3. The guidance includes best management practices summarized by cities for cities including topics beyond just regulatory concerns.

Video on sediment removal

A short video highlighting key topics for sediment removal projects is also now available on the MPCA web site. The video 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 that municipalities may want to consider when doing a sediment removal project.

Grant money

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
• Roseville
• Waconia
• White Bear Lake

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.

More information is provided in the MPCA fact sheet  Coal-tar Based Sealcoat - Environmental Concerns (wq-strm4-12) .

This 2012 article in Environmental Science and Technology provides 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. Coal-Tar-Based Pavement Sealcoat and PAHs - Implications for the Environment, Human Health, and Stormwater Management (tdr-g1-13)

MS4 permittees

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

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 (PDF Version) (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 lakes impacted by the collection, treatment and conveyance of stormwater.

Frequently Asked Questions

Municipalities 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.

MPCA contact

For more information on PAH contaminated dredge material from stormwater best management practices or for more information on prevention, contact Don Berger at 651-757-2223 or Don.Berger@state.mn.us.

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 (tdr-g1-15)
• Summary of Coal Tar-based Sealant Bans/Restrictions in the United States (tdr-g1-12)
• 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 (tdr-g1-07)
• Symposium - PAHs in Our Environment – Their Science and Regulation
• 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