[Federal Register Volume 61, Number 56 (Thursday, March 21, 1996)]
[Proposed Rules]
[Pages 11597-11599]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-6561]



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ENVIRONMENTAL PROTECTION AGENCY
[FRL-5443-4]

40 CFR Part 300


National Oil and Hazardous Substances Pollution Contingency Plan 
National Priorities List

AGENCY: Environmental Protection Agency.

ACTION: Notice of Intent to Delete the New Castle Spill Site from the 
National Priorities List (NPL).

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SUMMARY: The Environmental Protection Agency (EPA) Region 3 announces 
its intent to delete the New Castle Spill Site (Site) from the National 
Priorities List (NPL) and requests public comment on this proposed 
action. The NPL constitutes Appendix B of 40 CFR part 300 which is the 
National Oil and Hazardous Substances Pollution Contingency Plan (NCP). 
EPA promulgated the NCP pursuant to section 105 of the Comprehensive 
Environmental Response, Compensation, and Liability Act (CERCLA) of 
1980, as amended. EPA and the Delaware Department of Natural Resources 
and Environmental Control (DNREC) have determined that all appropriate 
CERCLA actions have been implemented and that the Site poses no 
significant threat to public health, welfare, or the environment. 
Therefore, further remedial measures pursuant to CERCLA are not needed.

DATES: Comments concerning the proposed deletion of the Site from the 
NPL may be submitted on or before April 22, 1996.

ADDRESSES: Comments may be submitted to Stephanie Dehnhard (3HW23), 
Remedial Project Manager, U.S. Environmental Protection Agency, 841 
Chestnut Building, Philadelphia, Pennsylvania, 19107, (215) 597-3167.
    Comprehensive information on this Site is available for viewing at 
the Site information repositories at the following locations:
    U.S. EPA, Region 3, Hazardous Waste Technical Information Center, 
841 Chestnut Building, Philadelphia, PA, (215) 597-6633. Delaware 
Department of Natural Resources and Environmental Control, 715 Grantham 
Lane, New Castle, DE, (302) 323-4540.

FOR FURTHER INFORMATION CONTACT: Stephanie Dehnhard (3HW23), U.S. EPA 
Region 3, 841 Chestnut Building, Philadelphia, PA, 19107, (215) 597-
3167.

SUPPLEMENTARY INFORMATION:

    I. Introduction
    II. NPL Deletion Criteria
    III. Deletion Procedures
    
[[Page 11598]]

    IV. Basis For Intended Site Deletion

I. Introduction

    The Environmental Protection Agency (EPA) Region 3 announces its 
intent to delete the New Castle Spill Site, New Castle, Delaware, from 
the National Priorities List (NPL), Appendix B of the National Oil and 
Hazardous Substances Pollution Contingency Plan (NCP), 40 CFR Part 300, 
and requests comments on this decision. EPA identifies sites that 
appear to present a significant risk to public health, welfare, or the 
environment and maintains the NPL has the list of those sites. As 
described in Section 300.425(e)(3) of the NCP, sites deleted from the 
NPL remain eligible for remedial actions in the unlikely event that 
conditions at a site warrant such action in the future.
    EPA will accept comments on the proposal to delete this Site from 
the NPL for thirty calendar days after publication of this notice in 
the Federal Register.
    Section II of this notice explains the criteria for deleting sites 
from the NPL. Section III discusses the procedures that EPA is using 
for this action. Section IV discusses the New Castle Spill Site and 
explains how the Site meets the deletion criteria.

II. NPL Deletion Criteria

    Section 300.425(e) of the NCP provides that sites may be deleted 
from, or recategorized on the NPL where no further response is 
appropriate. In making a determination to delete a site from the NPL, 
EPA considers, in consultation with the state, whether any of the 
following criteria has been met:
    (i) Responsible parties or other parties have implemented all 
appropriate response actions required;
    (ii) All appropriate Fund-financed response under CERCLA has been 
implemented, and no further action by responsible parties is 
appropriate; or
    (iii) The remedial investigation has shown that the release poses 
no significant threat to public health or the environment and, 
therefore, taking of remedial measures is not appropriate.
    Sites may not be deleted from the NPL until the state in which the 
site is located has concurred on the proposed deletion. EPA is required 
to provide the state with 30 working days for review of the deletion 
notice prior to its publication in the Federal Register.
    Pursuant to the NCP, 40 CFR 300.425(e)(3), all sites deleted from 
the NPL are eligible for further Fund-financed remedial actions should 
future conditions warrant such action. When there is a significant 
release from a site deleted from the NPL, the site can be restored to 
the NPL without application of the Hazard Ranking System.

III. Deletion Procedures

    Section 300.425(e)(4) of the NCP sets forth requirements for site 
deletions to assure public involvement in the decision. During the 
proposal to delete a site from the NPL, EPA is required to conduct the 
following activities:
    (i) Publish a notice of intent to delete in the Federal Register 
and solicit comment through a public comment period of a minimum of 30 
calendar days;
    (ii) Publish a notice of availability of the notice of intent to 
delete in a major local newspaper of general circulation at or near the 
site that is proposed for deletion;
    (iii) Place copies of information supporting the proposed deletion 
in the information repository at or near the site proposed for 
deletion; and,
    (iv) Respond to each significant comment and any significant new 
data submitted during the comment period in a Responsiveness Summary.
    If appropriate, after consideration of comments received during the 
public comment period, EPA then publishes a notice of deletion in the 
Federal Register and places the final deletion package, including the 
responsiveness summary, in the Site repositories.
    Deletion of a site from the NPL does not itself create, alter, or 
revoke any individual's rights or obligations. As stated in Section II 
of this Notice, Sec. 300.425(e)(3) of the NCP provides that the 
deletion of a site from the NPL does not preclude eligibility for 
future response actions.

IV. Basis for Intended Site Deletion

    The following site summary provides EPA's rationale for the 
proposal to delete the New Castle Spill Site from the NPL.
    The Site is a former manufacturing plant of the Witco Corporation 
(Witco) located 0.5 miles west of the Delaware River and 0.5 miles 
north of the City of New Castle, Delaware. Surrounding the Site is a 
mixed commercial and residential area. The Site is bordered on the west 
by a marsh and on the east by a dual highway.
    Among the chemicals Witco used in the production of plastic foams 
was the semi-volatile organic compound tris(2-chloropropyl) phosphate 
(Tris). Sometime before 1977 it is estimated that approximately 4-5 
drums of Tris, stored on the Site, were spilled on the ground 
contaminating the soil and shallow ground water beneath. Under the 
direction of DNREC, the ground water was pumped and discharged into the 
adjacent marsh. Numerous investigations of the soil and ground water 
followed, including an EPA Site Inspection in 1981. EPA proposed the 
Site for inclusion on the NPL on December 30, 1982 and finalized the 
listing on the NPL on September 8, 1983.
    Pursuant to an Administrative Order on Consent with DNREC, Witco 
conducted a remedial investigation (RI) and feasibility study (FS) from 
February 1988 to June 1989. These studies determined the extent of 
contamination, the risks to human health and the environment posed by 
the contamination, and cleanup alternatives to address those risks. The 
RI included sampling of soils, ground water, surface water, and marsh 
sediments.
    Results of the RI showed that the ground water in the shallow 
Columbia aquifer was contaminated with the organic compounds Tris, 
trichloroethylene (TCE), and 1,2-dichlorethene. Only Tris was 
determined to be present at levels that presented a significant risk to 
human health. TCE was determined to be from another source upgradient 
of the Site and was addressed through a separate State action. No Tris 
contamination was found in the deeper Potomac aquifer. Tris and several 
other organic compounds were found in soil samples but at levels that 
would not threaten human health or the environment and were no longer 
considered a source of contamination to the ground water. Contaminant 
levels found in the marsh area were well below levels that would 
threaten the wetland habitat or environmental receptors.
    Using the RI data, an endangerment assessment was performed to 
evaluate the risks that contaminants detected at the Site posed to 
human health and the environment. Of the numerous exposure pathways 
evaluated, only potential future exposure to ground water used as a 
potable water supply was determined to present a risk to human health 
that exceeded acceptable levels as defined by the NCP. As no one was 
using the Columbia aquifer in the area for a potable water supply, 
natural attenuation was determined to be the most appropriate means by 
which to reduce the Tris concentrations to acceptable levels. EPA 
developed a health-based drinking water cleanup level of 4.4 mg/l for 
Tris and estimated that it would take approximately four years for Tris 
to reach this level by natural attenuation.
    To document this cleanup approach, EPA and DNREC issued a Record of 
Decision (ROD) on September 28, 1989 which included the following

[[Page 11599]]
components: (1) Monitoring of the Columbia aquifer on a quarterly basis 
for Tris to ensure the effectiveness of the natural attenuation 
process; (2) monitoring of the Potomac aquifer on an annual basis for 
Tris to ensure that contamination has not migrated from the Columbia 
aquifer; (3) monitoring of the surface water and sediments of the 
adjacent wetlands on an annual basis for Tris, with further evaluation 
and bioassay testing required if trigger values of 100 ug/l Tris in 
surface water, or 1000 ug/kg Tris in sediments were reached; (4) 
institutional restrictions on the placement of wells in the Columbia 
aquifer in the vicinity of the Site; and, (5) a five year effectiveness 
review of the remedy.
    Public participation was encouraged in the remedy selection 
process. Prior to issuing the ROD, EPA and DNREC had released a 
proposed plan outlining the cleanup alternatives developed in the 
feasibility study and the preferred remedy. A public comment period 
followed the proposed plan's release from August 22, 1989 to September 
22, 1989. A public meeting was held on September 6, 1989 to discuss the 
proposed plan. All public comments were addressed and documented in the 
responsiveness summary which is part of the ROD.
    In April 1991, EPA and Witco entered into a Consent Decree whereby 
Witco agreed to implement the remedy selected in the ROD. Witco began 
quarterly ground water, surface water, and sediment monitoring in July 
1992 which continued through September 1995. Tris levels in the surface 
water and sediment samples were consistently well below the trigger 
levels specified in the ROD or not detected at all; therefore, no 
further evaluation or bioassay testing was necessary in the marsh. Tris 
was not detected in the Potomac aquifer in any sampling event.
    Of the 13 monitoring wells screened in the Columbia aquifer that 
were included in the monitoring program, only two wells showed 
concentrations of Tris above the ground water cleanup level of 4.4 mg/l 
during the entire monitoring period. By natural attenuation, Tris 
concentrations decreased with time in these two wells until they were 
below the cleanup level for the last several sampling events. During 
the last sampling event in September 1995, Tris concentrations ranged 
from approximately 1 to 2 mg/l. A statistical analysis of the data 
confirmed that there is very little chance that the Tris concentration 
will exceed the cleanup level in the future.
    In November 1990, pursuant to the ROD, DNREC instituted a Ground 
Water Management Zone (GMZ) in the vicinity of the Site to restrict 
installation of drinking water wells in the area. Now that the Tris 
cleanup level has been achieved in the area of the Site and there is no 
longer a need to prevent exposure to the ground water, DNREC will 
retract the GMZ following the deletion of the Site from the NPL.
    Based on the information presented above, EPA has determined that 
Witco, the responsible party for this Site, has implemented all 
response actions required and that no further action is appropriate. 
Thus, the required NPL deletion criteria presented in Section II, 
above, have been met. DNREC has concurred on this determination. 
Correspondence documenting this concurrence is included in the 
supporting documentation.
    The ROD stated that EPA would conduct a five-year effectiveness 
review to reevaluate the Site. The evaluation made to determine if the 
NPL Deletion criteria have been met serves as that review. In addition, 
EPA reviewed the most recent toxicological information available for 
Tris and determined that the cleanup level of 4.4 mg/l in ground water 
remains protective. Therefore, EPA has determined that the Site poses 
no significant threat to public health or the environment.
    The NCP at 40 CFR 300.430 states that EPA shall review remedial 
actions every five years if hazardous substances, pollutants, or 
contaminants remain at the site above levels that allow unrestricted 
exposure and unlimited use. Since neither of these conditions exists at 
this Site, further five-year reviews are not warranted and will not be 
conducted.
    EPA, with the concurrence of DNREC, believes that the criteria for 
deletion of the Site have been met. Therefore, EPA is proposing 
deletion of the Site from the NPL. Documents supporting this action are 
available in the site repositories of information.

    Dated: March 8, 1996.
Alvin R. Morris,
Acting Regional Administrator, U.S. EPA Region 3.
[FR Doc. 96-6561 Filed 3-20-96; 8:45 am]
BILLING CODE 6560-50-P