Residual Thorium Issues
As Mayor of West Chicago, I am gratified to report that
any lingering questions related to the residual thorium issues
raised at some homes within our community should be satisfied
this year. I established a joint team with the EPA, the State
of Illinois and Tronox, to encourage and track responses to
our concerns. That team has remained committed to the goal
of ensuring that those 32 properties initially cleaned up in the
1980s when standards were less strict, be re-tested to meet
new Agency guidelines. This is being accomplished by a procedure
developed by the EPA.
Since late in 2007 and 2008, 23 of the 32 properties have
been tested through surface gamma scans, downhole gamma
logging and soil sampling. The EPA has recently obtained
access to four of the remaining nine identified properties, and
testing at those properties will take place this spring. Efforts to
obtain access to the last five properties continue. I have
offered the City’s assistance to the EPA with those efforts.
Additionally, files from both the original clean-ups in the
1980s and the 1990s/2000 were reviewed to confirm that the
correct areas were targeted for this additional testing.
The EPA has completed a thorough evaluation of each of
the 23 properties tested so far to address the serious concerns
I have raised on behalf of our community. To date, they have
done more than 1,100 boreholes, and found only 11 with any
elevated reading at all. While those readings may be due to
residual thorium, they may also be due to substances like fertilizers,
bricks or other common materials. Those 11 boreholes
were located on 8 properties, two of which are owned by
Tronox and which were unoccupied houses. The EPA collected
at least one soil sample from each borehole with an elevated
reading and found only 5 (less than one-half percent) that
had a reading above 7.2 pCi/g, which is the current clean-up
standard. Those five readings were located on four properties,
again two of which are owned by Tronox.
It is important to note that every elevated reading, whether
from a surface scan, or downhole logging, does not mean that
thorium above the clean-up standard is present. Based on the
work done by EPA to date, it is clear that very little residual
thorium in excess of the clean-up standard is present on the
tested properties, and then only on a very few properties.
The EPA will continue its testing program until all of the
questioned properties are evaluated. For those few isolated
spots found to have residual thorium, the EPA will provide
that information to Tronox, who has already agreed
to address the findings.
I am committed to pressing the EPA and
Tronox to continue to understand the City’s
concerns and address them quickly, so that
our community can be assured that the residual
thorium question is finally behind us.
Michael B. Kwasman, Mayor