Indoor Inhalation Amendments and Other TACO Updates
On May 16, 2013, the Illinois Pollution Control Board added the indoor
inhalation exposure route to Illinois EPA’s risk-based cleanup methodology
called the Tiered Approach to Corrective Action Objectives, 35 Ill. Adm. Code
742 (TACO). These
amendments are effective on July 15, 2013.The purpose of the indoor inhalation amendments is to minimize the exposure
occupants to volatile chemicals that have the potential to migrate from the soil
groundwater to indoor air. This migration process is called vapor intrusion.
The indoor inhalation pathway will be managed similarly to the existing
exposure routes under TACO.
It follows the basic framework of TACO’s three tiers, includes calculations for
both residential and
industrial/commercial remediation objectives, and allows for pathway exclusion,
including the use of
building control technologies to prevent or minimize human exposures to
Inserting a new exposure route into TACO required comprehensive changes to
the existing regulations.
As would be expected, these amendments contain new definitions, equations,
remediation objectives, and mechanisms for managing the indoor inhalation
Illinois EPA is preparing fact sheets to help cleanup program participants
comply with the indoor inhalation amendments. We’re also coordinating with the
Environmental Regulatory Group to offer training webinars in the spring. Details
posted here when available.
In the meantime, here are answers to common questions about the proposed rule.
Q. Will Illinois EPA re-open sites that have already earned a No Further
Remediation letter and require them
to evaluate the indoor inhalation pathway?
A. No. Illinois EPA would take action only if new site-specific information
indicates a vapor intrusion problem.
Q. I have an approved remedial action plan under the existing TACO
regulations. What happens if the rule
takes effect before I receive the final NFR letter?
A. You will be required to evaluate the indoor inhalation exposure route in
accordance with the amendments. Please note that the NFR letter does not need to
be issued prior to effective date as long as all of the information required to
issue NFR is received prior to the effective date. For example, in the case of a
site where a Highway Authority Agreement has been submitted to IDOT and
completion report has been submitted to Illinois EPA before the July 15, 2013
effective date of the rules, indoor inhalation does not need to be addressed to
be eligible for NFR.
Q. What other changes do these amendments make?
A. Certain tables are being updated for all chemicals, not just volatile
chemicals, to minimize confusion and avoid complicating the footnotes. The
updated tables include the Similar-Acting Noncarcinogenic and Carcinogenic
Chemicals in Appendix A, Tables E and F, and the Default Chemical and Physical
Parameters in Appendix C, Table E.
fact sheet introduces concepts unique to the indoor inhalation exposure
route and describes the specific changes being made to the Subparts and Tables.
Other Fact Sheets
Pathway Exclusion of the
Indoor Inhalation Exposure Route
Modified J&E Model
Soil Gas Sampling Protocol
Indoor Inhalation Exposure Route at SRP Sites
Intrusion Assessment for Leaking UST Program Sites
School Sites with Environmental Cleanups
Addressing the Indoor Inhalation Pathway