Southeast Rockford Groundwater Contamination Superfund Project: Update Residential Indoor Air Sampling

              UPDATE
Southeast Rockford Groundwater Contamination Superfund
Project
Residential Indoor Air Sampling
March 2003
Rockford, Illinois
When will the Illinois EPA conduct indoor air sampling?
The Illinois Environmental Protection Agency (Illinois EPA) plans to sample indoor air in at least ten
Southeast Rockford homes in late May or June. Actual sample dates depend upon the weather. At least
five of these homes will be in the residential neighborhood near Area 7 and five in the neighborhood
near Area 4. (See the map below.)
Why is the Illinois EPA sampling indoor air?
The Illinois EPA has found groundwater (water beneath the ground) contaminated by volatile organic
compounds (VOCs) in Southeast Rockford. VOCs are compounds containing carbon that volatilize
(evaporate or turn to vapor) readily under certain conditions. These contaminants originate from four
major source areas. (See the map below.) In 1992 and 1993, the Illinois EPA tested indoor air in homes
located near the source areas to make sure that vapors from these contaminants were not seeping into
nearby basements.
The Illinois Department of Public Health and Illinois EPA evaluated the 1992 and 1993 sample results
and determined that harmful levels of vapors were not in the basements sampled. Since harmful levels
of vapors were not found in homes near the sources of contamination, there was no need to sample
homes farther away. The Illinois EPA is resampling homes this spring to make sure that conditions have
not changed.
Why isn't the Illinois EPA sampling homes near Areas 9/10 and 11?
The Illinois EPA does not plan to sample homes near Areas 9/10 and 11, because those homes are
located a greater distance from the source areas and, for the most part, are upgradient from these
areas. Upgradient means that contaminated groundwater is flowing from the source away from the
homes.
Will the sampling this spring differ from sampling conducted in 1992 and 1993?
Yes, somewhat. Recently, the U.S. Environmental Protection Agency (U.S. EPA) issued new draft final
guidance on evaluating the possibility of underground VOC vapors entering homes. In 1992 and 1993,
the State of Illinois was in the forefront of this type of investigation since indoor air sampling was not
routinely performed at sites with VOC contamination. Since that time, scientists have increased their
understanding of VOCs. They have also increased their understanding of equipment used in indoor air
monitoring, so both the sampling methods and the guidelines for evaluating the results have improved.
The new draft guidance incorporates this new knowledge.
This draft guidance has gone through extensive review, and the U.S. EPA believes it is a technically
sound document. The U.S. EPA accepted public comments on the draft guidance until February 27,
2003. That agency is now in the process of evaluating those comments to determine whether the draft
guidance is acceptable, or whether it should be changed in response to public comments. The Illinois
EPA will use the draft guidance to evaluate the indoor air sample results.
How will the Illinois EPA decide which houses to sample?
Residential Indoor Air Sampling Update - Southeast Rockford Groundwater Contaminati... Page 1 of 4
http://www.epa.state.il.us/community-relations/fact-sheets/southeast-rockford/southeast-ro... 5/25/2012