THE GREAT LAKES BlNATIONAL TOXICS STRATEGY
The Pacts about Coal Tar Sealants (CTS)
WHAT ARE COAL TAR SEALANTS?
Coal tar sealants (CTS) are used to protect, maintain and beautify
asphalt pavement for driveways and parking lots.
WHY ARE COAL TAR SEALANTS USED?
Asphalt pavement develops cracks overtime, and sealants may
help protect the pavement surface. However, CTS are only one
method of maintaining pavement.
PROBLEMS WITH COAL TAR SEALANTS
•	Coal tars and coal tar pitches are "known to be human
carcinogens" according to the U.S. Dept. of Health and Human
Services
•	CTS contain 3.4% to 20% polycyclic aromatic hydrocarbons
(PAHs) dry weight. PAHs are toxic to aquatic life, and several
are suspected human carcinogens.
•	CTS are a source of PAHs in stormwater runoff
•	PAH "hot spots" are found in streams adjacent to parking lots
using CTS
•	CTS contribute more PAHs to runoff than viable alternatives
LIMITATIONS OF COAL TAR SEALANTS
•	Tend to dry, shrink and crack with time
•	Need reapplication about every 2 to 5 years, depending on wear
•	Can cause surfaces to become slippery when wet
ALTERATIVES TO COAL TAR SEALANTS
•	Consider using asphalt-based sealers, which contain 0.03% to
0.66% PAHs, much less than CTS
•	Evaluate using permeable asphalt, which does not need
sealed and allows stormwater to infiltrate
•	Explore using gravel and concrete, which do not require
sealant and reduce the urban heat island effect
•	Promote shared driveways and parking lots to reduce the
need for paved surfaces
BE INFORMED
For more information about
the effect of coal tar sealants
on the environment visit
http://water.usqs.gov/nawqa/
asphalt sealers.html or
contact Barbara Mahler of the
U.S. Geological Survey at
bimahler@usqs.gov.
BE PROACTIVE
Municipalities may choose to
restrict the sale and/or use of
CTS in their community. It is
already happening! The City
of Austin, TX and Dane
County, Wl have banned the
use and sale of CTS. Visit
http://www.citvofaustin.org/
watershed/coaltar ban.htm
for more information.
BE CREATIVE
Consider the alternatives.
Grid gravel and pervious
concrete provide added
benefits such as stormwater
management, groundwater
recharge, durability, and an
enhanced aesthetic quality.
The Great Lakes Binational Toxics Strategy is committed to reducing or eliminating persistent toxic
substances, especially those which bioaccumulate, from the Great Lakes Basin.
For more information see http://epa.gov/greatlakes/bns/.
April 2008

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