[Federal Register Volume 65, Number 99 (Monday, May 22, 2000)]
[Proposed Rules]
[Pages 32058-32060]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-12520]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 300

[FRL-6702-5]


National Oil and Hazardous Substances Pollution Contingency Plan; 
National Priorities List

AGENCY: Environmental Protection Agency.

ACTION: Notice of intent to delete the Schofield Army Barracks site 
from the National Priorities List.

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SUMMARY: The Environmental Protection Agency (EPA) Region 9 announces 
the intent to delete the Schofield Army Barracks site (``the 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), which EPA promulgated pursuant to section 105 
of the Comprehensive Environmental Response, Compensation and Liability 
Act (CERCLA) of 1980, as amended. EPA and the State of Hawaii 
Department of Health have determined that the remedial action for the 
site has been successfully executed.

DATES: Comments concerning the proposed deletion of the Site from the 
NPL may be submitted on or before June 21, 2000.

ADDRESSES: Comments may be mailed to: Mark Ripperda, USEPA Region 9, 75 
Hawthorne Street, San Francisco, CA 94105, Mail Code SFD-8-3.
    Comprehensive information on this site is available through the 
Region 9 public docket which is available for viewing by appointment 
only. Appointments for copies of the background information from the 
Regional public docket should be directed to the EPA Region 9 docket 
office at the following address: Superfund Records Center, USEPA Region 
9, 75 Hawthorne Street, San Francisco, CA 94105.
    The deletion docket is also available at the following locations on 
Oahu: Wahiawa Public Library, 820 California Avenue, Wahiawa, Hawaii 
96786; and Directorate of Public Works, Environmental Division, Bldg 
105, 3rd Floor, Wheeler Army Airfield, Hawaii.

FOR FURTHER INFORMATION CONTACT: Mark Ripperda, USEPA Region 9, 75 
Hawthorne Street, San Francisco, CA 94105, Mail Code SFD-8-3; phone 
(415) 744-2408.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Introduction
II. NPL Deletion Criteria
III. Deletion Procedures
IV. Basis of Intended Site Deletion

I. Introduction

    The U.S. EPA Region IX announces its intent to delete the Schofield 
Army Barracks site in Honolulu County, Hawaii, 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), 
which EPA promulgated pursuant to section 105 of the Comprehensive 
Environmental Response, Compensation and Liability Act (CERCLA) of 
1980, as amended. EPA identifies sites that appear to present a 
significant risk to public health, welfare, or the environment and 
maintains the NPL as the list of these sites. EPA and the State of 
Hawaii Department of Health have determined that the remedial action 
for the site has been successfully executed.
    EPA will accept comments on the proposal to delete this site for 
thirty (30) days after publication of this document in the Federal 
Register.
    Section II of this document explains the criteria for deleting 
sites from the NPL. Section III discusses the procedures EPA is using 
for this action. Section IV discusses the Schofield Army Barracks site 
and explains how the site meets the deletion criteria.

II. NPL Deletion Criteria

    Section 300.425(e)(1) of the NCP provides that releases may be 
deleted from, or recategorized on the NPL where no further response is 
appropriate. In making a determination to delete a release from the 
NPL, EPA shall consider, in consultation with the appropriate State, 
whether any of the following criteria have been met:
    (i) Responsible parties or other persons have implemented all 
appropriate response actions required; or
    (ii) All appropriate Fund-financed responses under CERCLA have been 
implemented, and no further response 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, remedial measures are not appropriate.
    Even if a site is deleted from the NPL, where hazardous substances, 
pollutants, or contaminants remain at the site above levels that allow 
for unlimited use and unrestricted exposure, EPA's policy is that a 
subsequent review of the site will be conducted at least every five 
years after the initiation of the remedial action at the site to ensure 
that the site remains protective of public health and the environment. 
If new information becomes available which indicates a need for further 
action, EPA may initiate additional remedial actions. Whenever there is 
a significant release from a site deleted from the NPL, the site may be 
restored to the NPL without application of the Hazard Ranking System.
    In the case of Schofield Army Barracks, the selected remedy is 
protective of human health and the environment. The Army will maintain 
the landfill cover and the water treatment system, and will perform 
long-term groundwater monitoring. The first five-year review will be 
conducted by EPA, the State of Hawaii Department of Health (HDOH), and 
the Army in the year 2002. Reviews will be conducted every five years 
thereafter.

III. Deletion Procedure

    The following procedures were used for the intended deletion of 
this site: (1) All appropriate response under CERCLA has been 
implemented and no further action by EPA or the Army is appropriate; 
(2) HDOH has concurred with the proposed deletion decision; (3) a 
notice has been published in the local newspapers and has been 
distributed to appropriate federal, state, and local officials and 
other interested parties announcing the commencement of a 30-day public 
comment period on EPA's Notice of Intent to Delete; and (4) all 
relevant documents have been made available in the local site 
information repositories.
    Deletion of the site from the NPL does not itself create, alter, or 
revoke any individual's rights or obligations. The NPL is designed 
primarily for

[[Page 32059]]

informational purposes and to assist Agency management. Section 
300.425(e)(3) of the NCP states that the deletion of a site from the 
NPL does not preclude eligibility for future response actions.
    EPA's Regional Office will accept and evaluate public comments on 
EPA's Notice of Intent to Delete before making a final decision to 
delete. If necessary, the Agency will prepare a Responsiveness Summary 
to address any significant public comments received.
    A deletion occurs when the Regional Administrator places a final 
Notice of Deletion in the Federal Register. Generally, the NPL will 
reflect deletions in the final update following the Notice. Public 
notices and copies of the Responsiveness Summary will be made available 
to local residents by the Regional Office.

IV. Basis of Intended Site Deletion

    The following site summary provides the Agency's rationale for the 
proposal to delete this site from the NPL.

Site Background and History

    Schofield Barracks was established in 1908 to provide a base for 
the Army's defense of Pearl Harbor and the entire Island of Oahu. 
Initial construction of the post occurred between 1909 and 1917.
    Schofield Barracks is headquarters for the 25th Infantry Division 
and 45th Support Group, and currently houses approximately 21,000 
individuals. General operations performed at Schofield Barracks include 
administration, training, and small-scale industrial operations 
(vehicle repair and maintenance, weapons refinishing, laundering, 
electrical equipment service, sewage treatment, and municipal 
activities).
    Schofield Barracks is in the north-central plateau of the Island of 
Oahu in the State of Hawaii. Schofield Barracks encompasses a total 
area of approximately 27.7 square miles and is divided into two 
sections, the East Range and the Main Post. Wheeler Army Airfield lies 
between the two Schofield Barracks sections. The town of Wahiawa is 
immediately north of the East Range. The town of Mililani is 
approximately 2 miles south of the East Range.
    The recent history of reported groundwater contamination at 
Schofield Barracks began in April 1985, when the Army informed the 
Hawaii Department of Health (HDOH) that the industrial solvent 
trichloro-ethylene (TCE) was detected in wells supplying drinking water 
to Schofield Barracks at a concentration of approximately 30 parts per 
billion (ppb). In response to the detection of TCE in the water-supply 
wells, the Army installed an air-stripper treatment system in 1986 to 
remove TCE from the drinking water.
    Schofield Barracks was placed on the NPL in September 1990 because 
of the risk posed to human health by the TCE contamination in a major 
drinking water aquifer. The Remedial Investigation identified two 
distinct plumes of TCE at Schofield; one originating from the on-base 
landfill and a larger plume originating in the East Range, several 
miles up-gradient from Schofield's municipal water supply wells. The 
East Range is a mountainous area marked by numerous deep ravines and 
heavy tropical vegetation. A distinct source was not found, though the 
general area of the source was defined by the monitoring well network 
and concentrations within the plume. The risk assessment concluded that 
the only risk to human health and the environment at Schofield under 
CERCLA was posed by the contaminated groundwater.

Response Actions

    Overall, the remedial investigations and feasibility studies 
evaluated possible actions for four areas of the site: Operable Unit 1 
(OU1) included the 10 most likely sources of the TCE contamination. 
Operable Unit 2 (OU2) included the groundwater plumes. Operable Unit 3 
(OU3) included 34 additional possible sources of surface and subsurface 
contamination. Operable Unit 4 (OU4) included the Former Schofield 
Barracks Sanitary Landfill.
OU1 and OU3
    The Record of Decision (ROD) for OU1, the most likely source areas, 
was signed by EPA on January 24, 1996. The ROD for OU3, the other 
possible source areas, was signed by EPA on November 8, 1996. Both RODs 
selected no action for these operable units because the remedial 
investigations showed that those areas were not currently sources of 
contamination to the groundwater. The remedial investigations produced 
no evidence that any of the sites in operable units 1 or 3 were 
originally sources of groundwater contamination. None of the sites in 
operable units 1 and 3 posed unacceptable risks to human health or the 
environment.
OU2
    This operable unit consists of groundwater under Schofield Barracks 
that is contaminated with TCE. The Army, EPA and HDOH considered 
whether this contamination could be remedied within the aquifer or 
treated at the wellhead prior to the water being distributed for public 
use. The objectives for remediation are reducing risks to human health 
and the environment and satisfying applicable or relevant and 
appropriate requirements (ARARs). EPA determined that the federal 
drinking water standards, known as maximum contaminant levels (MCLs), 
are relevant and appropriate requirements within the aquifer. However, 
EPA may waive an ARAR where a selected remedy protects human health and 
the environment and it is technically impracticable to satisfy the 
requirement.
    Remediation within the aquifer can be pursued either through 
natural attenuation or with some type of active treatment. While 
natural attenuation appears effective at confining the plume to its 
current configuration, the concentrations of TCE within the plume are 
decreasing too slowly for it to be considered a viable remedy. Active 
treatment of the groundwater is not practicable because of the 
hydrogeological conditions at the site. The depth to the water table is 
over 500 feet, the aquifer is composed of fractured volcanic rock, the 
aquifer is over 1000 feet thick, and approximately 120 million gallons 
of groundwater flow through the aquifer per day. Because of these 
conditions, the Army, EPA and HDOH concluded that treating the 
groundwater to achieve the MCL for TCE within the aquifer is 
technically impracticable. Therefore, EPA granted a technical 
impracticability (TI) waiver to this ARAR for OU2. However, the final 
remedy is fully protective of human health and the environment because 
the water will be treated before being distributed for public use.
    The ROD for OU2, the groundwater aquifer, was signed by EPA on 
February 7, 1997. The selected remedy included the following actions:
     Continued treatment of contaminants in the Schofield 
Barracks Water Supply Wells by air stripping at the wellhead;
     The Army must consult with EPA and DOH prior to abandoning 
the water supply wells, because production at these wells may help to 
control plume migration;
     The Army must conduct semi-annual sampling and analysis of 
water supply wells, agricultural wells and monitoring wells in the 
region;
     The Army prepared plans to implement the contingency of 
wellhead treatment on water supply wells throughout the region. The 
Army will be required to install treatment systems on any wells that 
are impacted by the plume from Schofield Barracks above

[[Page 32060]]

one-half the maximum contaminant level (MCL) as established under the 
Safe Drinking Water Act;
     The Army must upgrade the treatment system or pay any 
incremental costs caused by contamination from Schofield Barracks at 
wells that already have a treatment system in place;
     Conduct five year reviews with the State of Hawaii and 
EPA.
    The following actions were taken to implement the remedy decision 
for OU2:
     The Army installed air-stripper treatment units on their 
four contaminated municipal water supply wells at Schofield and will 
continue to operate the treatment system as long as contaminants in the 
influent water are above maximum contaminant levels (MCLs) specified in 
the Safe Drinking Water Act.
     The Army has sampled drinking water wells, agricultural 
wells and monitoring wells semi-annually throughout the central plateau 
area of Oahu since 1993 and will continue to do so until such time as 
the Army, EPA and HDOH agree that contaminant levels throughout the 
plume are below action levels.
     The groundwater contaminant plume appears to be confined 
by a system of dike impoundments and natural attenuation. The EPA, HDOH 
and the Army believe that it will not impact any additional down-
gradient wells. Therefore, the contingency remedy for additional 
wellhead treatment is not expected to be needed.
     Institutional controls have been implemented that will 
restrict the placement of new drinking water wells into the contaminant 
plume. The Honolulu Board of Water Supply controls the installation of 
drinking water wells via a permit process. They will require the 
installation of wellhead treatment, paid for by the Army, on any wells 
that are drilled into the plume area.
OU4
    The ROD for OU4, the landfill, was signed by EPA on September 26, 
1996. The selected remedy included the following actions:
     Access restrictions and site security to limit human 
exposure to the landfill contents, prevent trespassing, and protect the 
integrity of the cap;
      Semi-annual ground water monitoring to monitor the 
effectiveness of the landfill site cap and determine groundwater flow 
directions in the vicinity of the landfill;
     Regrade the existing landfill cover;
     Remove Guinea grass from the existing cover and revegetate 
to improve future cap maintenance;
     Perform long-term maintenance of the landfill cover;
     Maintain existing passive landfill gas venting; and
     Install additional gas monitoring points at the perimeter 
of the landfill.
    The following actions were taken to implement the remedy decision 
for OU4:
     The Army installed chain-link fence around the perimeter 
of the accessible portions of the landfill as an access restriction and 
has installed signs warning of potential health risks. The Former 
Landfill is part of a military installation that has a guard stationed 
at the entrances to monitor access to the installation 24 hours per 
day.
     The Army completed regrading the cover, installing nine 
new multi-level gas probes, stabilizing the sideslopes, and replacing 
and improving the vegetative cover in June 1998.
     The Army has conducted semi-annual groundwater monitoring 
and quarterly gas probe monitoring since the completion of the remedial 
action in June 1998. The groundwater monitoring is conducted as part of 
the OU2 work and it shows that the groundwater plume around the 
landfill is stable and at low levels of TCE concentration. The gas 
probe monitoring typically detects methane in four out of the 27 gas 
probe sampling points. The highest detection during the February 2000 
monitoring event was 0.2 percent, which is well below the acceptable 
limit of 5 percent.
    On July 21, 1998, the Army, EPA and HDOH, conducted a final 
inspection and determined that the remedial action had been 
successfully executed for all OUs. EPA reclassified Schofield Barracks 
to construction complete status in September 1998.

Operation and Maintenance

    The Army is responsible for conducting long-term maintenance and 
upkeep of the landfill cover and for monitoring landfill gas, 
groundwater, and drinking water wells, in accordance with the approved 
Long-Term Operation, Maintenance and Monitoring Plans for OUs 2 and 4.

Five Year Reviews

    CERCLA requires a five-year review of all sites with hazardous 
substances remaining above the health-based levels for unrestricted use 
of the site. Since the cleanup of the site utilized containment of 
hazardous materials within the landfill and wellhead treatment for 
drinking water, the five-year review process will be used to ensure 
that human health and the environment remain protected in the future. 
The first five-year review is scheduled for the year 2002.

Community Involvement

    The Army published its final Community Relations Plan on January 
31, 1997, after interviews with local residents and officials. An 
information repository was established at the Wahiawa Public Library 
and all reports and fact sheets were sent to the repository as they 
were completed.
    The Army conducted public meetings prior to completing each of the 
four Records of Decision, and the public had no negative comments about 
any of the actions at Schofield.

Applicable Deletion Criteria and State Concurrence

    EPA has determined that all appropriate responses under CERCLA at 
Schofield Army Barracks have been completed, and that no further CERCLA 
response is appropriate to protect human health and the environment. 
The Hawaii Department of Health concurred with the proposed deletion of 
the site from the NPL in a letter dated March 13, 2000. Therefore, EPA 
proposes to delete the site from the NPL. Documents supporting this 
action are available from the docket at the Region 9 office and in the 
Army's docket on Oahu.

    Dated: April 25, 2000.
Felicia Marcus,
Regional Administrator, Region IX.
[FR Doc. 00-12520 Filed 5-19-00; 8:45 am]
BILLING CODE 6560-50-P