2.1.1 Narrative
TRW, Inc. (the PRP at the site) has agreed to perform the
following actions to reduce TCE concentrations in the cave and gift shop:
1. Two ventilation wells will be installed on the main trunk of the cave system
upstream of the Jungle Room. The vent wells will be outfitted with blowers at
the ground surface designed to withdraw air from the cave. The operation of the
blowers may vary depending on weather conditions. The purpose of the system is
to capture and vent air that has migrated through the cave before it reaches
the developed portion of the cave.
2. An
evaluation will be conducted of the heating, ventilation and air conditioning
(HVAC) system in the gift shop to determine whether appropriate modifications
are necessary to reduce the amount of cave air entering the gift shop building.
This evaluation will be provided within 60 days after the ventilation wells
have been pilot tested and are fully operational or sooner.
3. Portable
air cleaners will be installed in the gift shop area, and the area between the
gift shop and the air lock doors. The cleaners will treat the air in these
areas to remove TCE. The continuing operation of these cleaners will be
evaluated as work is completed and may continue as necessary.
4. The
existing air lock doors will be upgraded and a signal system installed to
indicate whether one or both doors are open to avoid accidental simultaneous
openings of both sets of doors.
5. An alternative source of water will replace the
use of contaminated spring water for cleaning and maintaining the cave
features.
2.1.2 Response Actions to Date
To date, the following actions have been completed:
installation of two ventilation boreholes with blowers, installation of
portable air cleaners, installation of a permanent airlock to replace the
temporary airlock; improvement of the air-sealing and ventilation control at
the main entrance; and evaluation and improvements of the amphitheater entrance
ventilation control.
2.1.3 Enforcement Activities, Identity of Potentially Responsible Parties (PRPs)
A potentially responsible party has been identified as
TRW, Inc. and they are performing the removal action with EPA oversight.
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