Indoor Inhalation Amendments and Other TACO Updates
On March 7, 2013, the Illinois Pollution Control Board adopted the
Second Notice proposal
to add the indoor inhalation exposure route to Illinois EPA’s risk-based
cleanup methodology, the Tiered Approach to Corrective Action
Objectives, 35 Ill. Adm. Code 742 (TACO).
During the 45-day Second Notice period, the proposal is reviewed by the
Joint Committee on
Administrative Rules (JCAR). The exact date of adoption depends on when the
amendments are
published in the Illinois Register. The effective date of the amendments
will be 60 days
after adoption and is estimated to be July 2013.
The purpose of the indoor inhalation amendments is to minimize the exposure
of building
occupants to volatile chemicals that have the potential to migrate from the soil
and
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
contamination.
Inserting a new exposure route into TACO required comprehensive changes to
the existing regulations.
As would be expected, these amendments contain new definitions, equations,
parameters, default
remediation objectives, and mechanisms for managing the indoor inhalation
exposure route.
Illinois EPA is preparing fact sheets to help cleanup program participants
understand and
comply with the indoor inhalation amendments. We’re also coordinating with the
Illinois
Environmental Regulatory Group to offer training webinars in the spring. Details
will be
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.
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.
This seven-page
fact sheet introduces concepts unique to the indoor inhalation exposure
route and describes the specific changes being made to the Subparts and Tables.
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