PB97-963135
EPA/541/R-97/122
January 1998
EPA Superfund
Record of Decision Amendment:
Brio Refining Inc.
Friendswood, TX
7/2/1997
-------
BRIO REFINING SUPERFUND SITE
HOUSTON, TEXAS
AMENDED RECORD OF DECISION
DECLARATION
SITE NAME AND LOCATION
Brio Refining Site, Houston, Texas
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected amended remedial action for the Brio
Refining Site in Houston, Texas, developed in accordance with CERCLA, as amended by SARA,
and, to the extent practicable, the National Contingency Plan. This decision is based on the
Administrative Record for the site.
The State of Texas concurs on the selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this amended Record of Decision (ROD), may
present an imminent and substantial endangerment to public health, welfare, or the environment.
DESCRIPTION OF THE REMEDY
This remedy amends the original remedy selected in the 1988 ROD. This containment
remedy replaces on-site incineration as selected in the 1988 ROD. The containment remedy will
reduce the risks associated with exposure to contaminated materials and inhibit the migration of
contaminated groundwater from the site.
The major components of the amended remedy include:
• Installing a sub-grade vertical barrier wall enclosing the site;
• Capping the site with a cover system consisting of compacted clay, liner, and gas
collection system;
• Constructing a groundwater flow control system to manage the migration of
contaminants within the containment system; and
• Improvement to Mud Gully to ensure flow capabilities within the drainage system.
-------
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the environment, complies with
Federal and state requirements that are legally applicable or relevant and appropriate to the
remedial action, and is cost-effective. This remedy utilizes permanent solutions and alternative
treatment technologies to the maximum extent practicable for this site. The remedy does not
employ treatment as a principal element, which does not satisfy the statutory preference for
treatment; however, treatment components are incorporated into the remedy to address principal
threats. Additional incorporation of treatment was not practicable because of short-term emission
concerns from intrusive remedies.
Because this remedy will result in hazardous substances remaining on-site above health-
based levels, a review will be conducted within five years after commencement of remedial action
to ensure that the remedy continues to provide adequate protection of human health and the
environment.
Pate
Acting Regional Administrator
-------
BRIO REFINING SUPERFUND SITE
HOUSTON, TEXAS
AMENDED RECORD OF DECISION
DECISION SUMMARY
This Amended Record of Decision (ROD) revises and supersedes portions of the original ROD. The
portions of the original ROD that remain effective are dismantling and disposition of process
equipment and site debris, site control, the recovery of dense non-aqueous phase liquid (DNAPL),
and off-site soil contamination. The Amended ROD summarizes the information that can be found
in greater detail in documents contained in the Administrative Record for the Brio site, and this
Amended ROD will become part of the Administrative Record as required by the NCP. The
development and evaluation of remedial alternatives to address the contamination are presented in
the Feasibility Study Report, the Memorandum of Technology Screening and Development of
Remedial Alternatives, and the Scope of Work
-------
Brio Local Community Relations Office San Jacinto College -
10904 Scarsdale, Suite 295 South Campus Library
Houston, Texas 77089 13735 Beamer Road
(713) 922-4750 Houston, Texas 77089
(713)992-3416
U.S. Environmental Protection Agency Texas Natural Resource
12th Floor Library Conservation Commission
1445 Ross Avenue Park 35 Circle on IH-35 N.
Dallas, Texas 75202-2733 P.O. Box 13087
(214)665-6444 Austin, Texas 78711 -3087
(512)239-1000
Community Relations
This Amended ROD was prepared with the direct input of the CAG. The CAG held over 20
meetings that were open to the public during the formation of the proposed alternative. EPA
provided a $50,000 Technical Assistance Grant to the CAG for the services of a technical advisor
during this process
A community relations office has been established to facilitate public comment and inquiries as to the
status of the site and site activities. As required by the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA) and the National Contingency Plan (NCP), 40 Code
of Federal Regulations (CFR), Section 300.43 5(c)(2)(ii), the EPA solicited public review and
comment on this Amended ROD. Public comments on this Amended ROD were solicited in a
comment period from April 7 to May 7, 1997. In addition, a public meeting was held on April 15,
1997, to solicit public comment. A Responsiveness Summary addressing public comments received
is attached to the Amended ROD.
SITE DESCRIPTION AND BACKGROUND
The Brio Refining Site is located almost 20 miles south of Houston, Texas, and occupies
approximately 58 acres. The site is divided by Dixie Farm Road, with Brio North being historically
used for storage purposes and Brio South being primarily used for processing activities. A
neighboring residential subdivision (Southbend, now abandoned) is located along and north of the
northern boundary of Brio North. Mud Gully, a flood control ditch and local tributary of Clear
Creek, runs along the western boundary of the Brio site. Figure 1 shows the general location of the
Brio site and the site layout.
In general, processing activities consisted of reclamation of petrochemicals from various source
materials, most of which were residues, tank bottoms, and tars of other processes performed at off-
-------
site locations. Most of the feedstock materials for processing at Brio were stored in on-site pits.
many of which were located on Brio North. However, the disposal areas were on both the Brio
North and South Sites. EPA finalized the site on the National Priorities List on March 31. 1989.
Numerous investigations, studies, and site activities have been performed at the Brio Site in efforts
to determine the exact location of the former storage pits and the nature and extent of contamination.
The investigations found that the majority of the contamination at the site is found within the location
of the former storage pit areas. The pits were constructed within the uppermost geologic unit which
is called the Upper Clay. This unit occurs across the entire site and ranges in depth from 14 to 32
feet.
The Numerous Sand Channel Zone (NSCZ) and the Fifty-Foot Sand (FFSZ) are the two main water
bearing units that have been investigated at the site. The NSCZ lies below the Upper Clay and is
comprised of interbedded sands and silry clays. The NSCZ is encountered from 15 to 30 feet below
ground surface. The groundwater in the NSCZ is heavily contaminated, low yielding, and typically
flows toward and discharges to Mud Gully. The thickness of the NSCZ varies from 10 to over 20
feet.
The Middle Clay Unit (MCU) separates the NSCZ from the underlying Fifty-Foot Sand. The MCU
forms a confining layer and ranges from 8 to 20 feet thick. The FFSZ contains low levels of
contamination and flows in a south-southeast direction.
Following the site investigations, EPA issued a ROD on March 31, 1988, that selected remedial
actions consisting of on-site incineration of pit residuals, removal of surface contamination, channel
improvements to Mud Gully, demobilization of remaining process equipment and removal of debris
on the site, removal of dense non-aqueous phase liquids (DNAPL) and pump and treat for
groundwater in the NSCZ. The ROD addressed all the threats at the site as a single operable unit,
including groundwater contamination. A consent decree was entered in April 1991 between EPA and
the Brio Site Task Force (BSTF) for implementation of the ROD.
-------
Brio
Refinery
Peorland
Friendswood Road
Figure 1 - Brio Refining Site Map
-------
A remedial design was performed by the BSTF and approved by EPA in July 1993. The design
covered all aspects of the ROD with the exception of DNAPL recovery. DNAPL recover) is
proceeding under a different construction track because the work is not dependant on the type of
source control performed.
Demolition of the majority of the remaining process equipment was completed prior to mobilization
of the incinerator. In addition, a temporary groundwater treatment system was installed to address
the movement of contaminated groundwater into Mud Gully in 1994.
A rotary kiln incinerator and support equipment were mobilized to the site following the demolition
work. Temporary enclosures were erected over the pits requiring remediation in order to contain
emissions during excavation. The incinerator began clean burn operations with imported material,
and excavation began at Pit R on Brio South for shakedown operations and to stockpile material for
the trial burn. Emission problems during excavation led to a "stop work" order until appropriate
emission control equipment could be installed. Before additional controls could be installed, other
events described below led to the submittal of a force majeure claim by the BSTF, which eventually
resulted in the decision by EPA to allow the dismantling of the incinerator. The incinerator and
support equipment was demobilized by December 1994. Since demobilization, the groundwater
treatment system has continued to operate, the DNAPL remediation has proceeded, and drums
stockpiled since the inception of investigations at the site were disposed of off-site.
SCOPE OF THIS RESPONSE ACTION
Rationale for Amending the Record of Decision
In response to requests by the public, a review of Brio Site issues, and the remedial action plan was
started in early 1993 by the EPA Superfiind Revitalization Office (SRO) and the Ombudsman from
EPA Headquarters Office in Washington D.C.. The results of this review were published in a
document referred to as the SRO Report on April 1, 1994. The report stated that several issues
needed resolution before continuing with implementation of the on-site incineration re.nedy. The
issues included additional site characterization, additional air monitoring, and continual stack testing
after the trial bum period.
In May 1994, the BSTF submitted a force majeure claim stating that the short-term air standards set
by EPA during the remedial design for the implementation of the remedial action would result in a
delay of compliance with the milestone schedule in the Consent Decree. On June 2, 1994, the BSTF
petitioned the EPA to alter the response action for the Brio site. The BSTF claimed that in addition
to the short-term air standards, the SRO report conflicted with the remedy and would substantially
delay implementation of the incineration. On June 28, 1994, EPA suspended the milestone schedule
and began an evaluation of options including the performance of a focused feasibility study. EPA
held a public meeting on July 14, 1994, to solicit input on the options under consideration. The
attendees of the meeting overwhelmingly favored discontinuing incinerator operations and studying
the use of a containment remedy at the site. On August 2, 1994, EPA notified the BSTF that its
petition, along with community input, provided a basis to re-evaluate the incineration remedy. EPA
-------
noted that in addition to information presented in the BSTF's petition the following information was
also considered:
- Emissions during excavation of site materials was higher than expected, resulting in the need
for rigorous engineering controls;
•>
- Engineering controls to abate the emissions would add significantly to the cost of the
remedy;
- Air monitoring showed that fugitive emissions could leave the site even in an undisturbed
state; and
- The detection of off-site dense non-aqueous liquids might lead to actions not considered in
the current ROD.
The BSTF demobilized the incineration unit, replaced soils excavated in preparation for the trial bum,
and began a re-evaluation of the site remedy through a focused feasibility study. The focused
feasibility study process stopped following the submittal of the Memorandum on Technology
Screening and Development of Remedial Alternatives in August 1995, after the CAG rejected the
proposed alternative developed by the BSTF. The containment alternative that is evaluated in this
Amended ROD was the result of the focused feasibility study submittals and discussions between
EPA, CAG, and the BSTF; and other information contained in the Administrative Record.
Remedial Action Objectives
The remedial action objectives for the response action include:
• Protection of the health and safety of the community, workers, and the environment during
implementation of the remedy;
• Minimization, to the extent practicable, of disruption and inconvenience to the community
during implementation of the remedy;
• Long-term, effective control of migration of leachable organic liquids from the source area;
• Long-term, effective control of off-site migration of free-phase liquids or site constituents
moving through the groundwater, surface water, soil, or air pathways;
• Long-term, effective reduction of potential future risk to the community and the environment
resulting from off-site exposure to site constituents by maintaining or achieving:
- Target levels of public exposure to air emissions
- Target levels of affected soil dermal contact and ingestion
- Control of off-site transport of affected soils to acceptable levels
-------
- Protection of existing aquatic life in Mud Gully, and
- Target levels of organic constituents in the Fifty-Foot Sand Zone within a reasonable
time;
• Minimization of potential negative impact of natural disasters such as flooding, hurricanes,
etc.; and
• Long-term, effective site control and aesthetics.
The Endangerment Assessment developed specific target levels to achieve public health and
environmental protection goals. The target levels are based on restricted access and a trespasser
scenario and established the goals shown in Table 1. The target levels utilize 1 x 10"6 as the basis for
calculating the concentrations. See the Administrative Record for more detailed information about
site risks.
This Amended ROD changes the basis for the action levels established for Mud Gully in the 1988
ROD. The standards utilized in 1988 were based on acute toxicity levels for protection of freshwater
aquatic life. The standards were updated by the State of Texas in 1990. The revised standards are
applicable to Mud Gully and Clear Creek and are presented in Table 2. In addition, a human health
criteria is being applied for consumption of fish only. A human health criteria was not utilized in the
1988 ROD, however, fish testing in Mud Gully and Clear Creek by the Texas Natural Resource
Conservation Commission (TNRCC) in 1993 and 1994 found detectable levels of volatile organic
compounds associated with the Brio site. The utilization of a human health criteria in these segments
is applicable for the consumption offish. When human health criteria exceed the freshwater water
quality criteria, the freshwater quality criteria (chronic) will be used. This applies in the case of 1,2
dichloroethane because the calculated human health criteria for the consumption of fish exceeds the
chronic water quality criteria.
In addition, an updated analysis of the remediation goals for the NSCZ adds a new criteria for off-site
migration of contaminated groundwater. The 1988 ROD did not contain an action level for NSCZ
groundwater. A criteria was eventually defined in the Scope of Work for the remedial design and was
based on drinking water criteria. This Amended ROD is based on a determination that surface water
standards are relevant and appropriate requirements for the NSCZ groundwater and should be applied
outside the waste management area (i.e. the vertical barrier wall described below).
-------
TABLE 1
TARGET LEVELS ESTABLISHED IN THE ENDANGERMENT ASSESSMENT
Constituent
Non- Carcinogenic
PNAs
Carcinogenic PNAs
Benzo(a)anthracene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Benzo(a)pyrene
Dibenzo(a,h)anthracene
Indeno{ 1 ,2,3,c,d)pyrene
Volatile Organic and
Base Neutral
Compounds
1 ,2 Dichloroethane
1 , 1 ,2 Trichloroethane
Bis(2-chloroethyl)ether
Vinyl Chloride
Methylene Chloride
Exposure Scenario (matrix)
Infrequent Trespass
Ingestion (Soil)
40,200 mg/kg
1 0,200 mg/kg
1,200 mg/kg
580 mg/kg
44 mg/kg
74 mg/kg
7,400 mg/kg
2800 mg/kg
4300 mg/kg
230 mg/kg
109 mg/kg
33,000 mg/kg
Inhalation (Soil)
3,700 mg/kg
2300 mg/kg
640 mg/kg
Aquatic Protection
(NSCZ Groundwater)
21,300mg/l
l,700mg/l
1 0,400 mg/l
4,700 mg/l
9,700 mg/l
Groundwater Ingestion
(Fifty Foot Groundwater)
3.8/jg/l
6.1/vg/l
1 A/g/1
47/jg/l
Off-site Ingestion (Soil)
40,200 mg/kg
26.9 mg/kg
5.1 mg/kg
5.1 mg/kg
.04 mg/kg
.23 mg/kg
10.5 mg/kg
.13 mg/kg
1.4 mg/kg
-07 mg/kg
.02 mg/kg
12.5 mg/kg
Note: The lowest value for each matrix applies.
-------
Table 2
Revised Surface Water Criteria
Compound
1 , 1 ,2 Trichloroethane
1 ,2 Dichloroethane
1,1 Dichloroethylene
Vinyl Chloride
Clear Creek
Criteria
41.8/zg/l
l,794Mg/l
87.4 i/g/1
94.5 /ug/1
Mud Gully Criteria
4180 A*g/l
20,000 Mg/1
8740 ^g/1
9450 A*g/l
SUMMARY OF ALTERNATIVES
The remedial alternatives evaluated in this Amended ROD include the original remedy selected in
the 1988 Record of Decision and the new selected remedy. EPA chartered the CAG in September
1994 to assist with the development of a containment alternative for the site. The new containment
alternative was based on focused feasibility submittals, discussions between the CAG, the Brio Site
Task Force and EPA and other information in the Administrative Record. EPA acted as a facilitator
between the GAG and the BSTF in developing the proposed containment alternative. The utilization
of this process resulted in a remedial alternative that contains elements essential to address the
concerns of the community. The new proposed alternative addresses the environmental threats at the
site, provides assurance of long-term protection from site hazards, and addresses other issues (e.g.
Mud Gully relocation) that are a priority to the community. EPA is utilizing this process on a pilot
project basis evaluating the use of CAGs in the development of remedial alternatives.
*
It is important to note that this plan does not amend the component in the original ROD addressing
DNAPLs. The DNAPL Delineation and Recovery Project that was ongoing as a separate project
during the mobilization of the incinerator was not suspended in 1994 and will continue as an element
of the Consent Decree with the BSTF.
Alternative 1 - On-site Incineration (1988 ROD)
Affected materials and soils - Shall be treated using either incineration or biological treatment.
This media shall be defined as all contaminated sludges and liquids and waste material found to
exist above the action levels defined in the Endangerment Assessment (EA). This will include those
affected materials and soils existing in pits B, J. H/V, E, Q, and R (as defined in the EA).
Additionally, the Remedial Investigation identified sludges and liquids in pits F, G, I, K, L, and M;
therefore, these sludges and liquids (and any others found during remedial action) must also be
excavated and treated. The definition of the boundary between the sludge/soil interface will be
determined prior to remedial action. Excavations shall be conducted in enclosures, material
-------
transported to the treatment unit(s), and the treated material will be backfilled in the pits if it
successfully passes the Toxicity Characteristic. Leaching'Procedure.
Surface contamination - Attachments 8 and 9 of the Remedial Investigation Report shall be
examined and the site re-evaluated, prior to remedial action, to identify those areas where surface
seeps are visually apparent. These areas will be scraped or excavated to remove the source of
contamination and to prevent future migration of this material. This source of contamination will
then be consolidated and treated with the affected materials and soils.
Off-site soil contamination - Any off-site soil contamination found during the remedial investigation
or during the remedial action shall be removed to background levels. This may require that special
detection limits be used for sampling efforts at the site boundaries during the remedial action. This
activity will have to be further defined in the remedial design.
Pit G - Further investigation into this pit area to locate sludges or liquids may have to be done at
the completion of the remedial action due to the location of this pit beneath the wastewater
treatment surface impoundment. This activity will be further defined in the remedial design.
Debris and rubble - There is much inert debris and rubble remaining on the site from past
operations. This material may be consolidated and the ultimate disposition of the material
determined during fhe remedial design.
*
Mud Gully - Contaminants observed in this flood control ditch and the "bottle neck" that exists as
it passes the Brio site has been a noted concern of the EPA as well as local residents and the Harris
County Flood Control District. It is apparent that these problems will have to be corrected as part
of any remedy that is instituted at the site. Initial thoughts would suggest a low-maintenance
approach to resolving this problem where some type of performance standard would be set in
cooperation with the Harris County Flood Control District. Such actions shall be further defined
in the remedial design.
Wastewater treatment system - In-place stabilization of wastes existing in the impoundments,
backfill impoundments with dike materials and other uncontaminated materials (if necessary), cap
and cover, grade to promote run-off and minimize infiltration, install a package wastewater
treatment plant or route wastewater to POTW. Portions of the existing wastewater treatment system
may be used during remedial action but will be decommissioned once the remedial action is
completed.
Storage tanks and drums - Remove tank contents, decontaminate tanks, dismantle tanks; sell
dismantled tanks or transport the tanks to an EPA approved off-site disposal facility; transport the
tank contents and drums to an EPA approved off-site disposal facility. If any tanks are used during
remedial activities, they will be dismantled upon completion.
Process equipment - The entire process facility will be dismantled. If any portion of the existing
facility is used during remedial activities, the structure will be dismantled upon completion of
10
-------
remedial action.
Monitoring and control of migration pathways - Ambient air sampling on a semi-annual basis,
control air emissions from treatment processes, excavate in enclosures and vent the enclosure to an
emission control device; eliminate or control rainfall on construction areas; sample and monitor
Mud Gully sediments; treat the ground water in the Numerous Sand Channel Zone to a level to be
determined in the remedial design (but to achieve treatment of the Dense Non-Aqueous Phase
Liquids (DNAPLs) to the satisfaction of EPA) monitor the groundwater for a time frame to be
determined in the remedial design; allow natural attenuation (no treatment) of the Fifty-Foot Sand
aquifer and monitor the groundwater in the aquifer to ensure that it is naturally cleaning itself.
Monitoring activities will be utilized to determine the effectiveness of the actions to be implemented
and shall be detailed in the operation and maintenance plan of the remedial design. This same data
will be evaluated during the Agency's 5-year review, in accordance with SARA Section 121 (c), to
determine if any corrective action is necessary.
Site management plan - Areas outside the boundaries of excavation will be regraded and vegetated
to promote drainage and minimize infiltration. A storm water transmission system draining to Mud
Gully will be constructed in an east/west direction across the north and south parcels. All regrading
will be covered with six inches of top-soil, if necessary, to promote vegetative growth. To the
maximum extent practicable, the aesthetics of the site (upon completion of the remedy) shall be
enhanced by utilizing creative design and landscaping techniques with input from local residents.
Site control - This remedial action is based on permanent site control, imposition of necessary deed
notices and restrictions (if possible), and restriction of access to the site by use of a fence or similar
barrier.
Alternative 2 - Cap and Barrier Wall (Containment)
The elements of this alternative include:
Vertical Barrier Wall - A sub-grade barrier wall will be constructed to limit the potential for off-site
migration of contaminated groundwater in the NSCZ. The wall will be designed to encompass the
site and will be keyed to the Middle Clay Unit. The technique of construction will be established in
the remedial design.
Site Cover - A composite cap will be constructed over the site, extending to the limits of the barrier
wall (not including Dixie Oil Processors South, see Figure 2). The cap will include a gas collection
layer, a flexible membrane liner, compacted clay, and top soil to promote vegetative growth.
Groundwater Flow Control - A groundwater pumping system will be installed within the barrier wall
to limit the migration of site contaminants. Recovered groundwater will be treated and discharged
to Mud Gully.
Air Monitoring and Long Terrq Groundwater Monitoring - An air monitoring system will be
11
-------
maintained during the construction of the remedy to protect public health. The groundwater will be
monitored in the FFSZ to ensure groundwater is below established Maximum Contaminant Levels
(MCLs). The NSCZ groundwater outside the barrier wall will be monitored to demonstrate
compliance with water quality criteria for Mud Gully.
Mud Gully - Similar to the original proposal, this option includes channel improvements to the gully,
but also allows the option of relocation of the gully by Harris County.
Common Components - In addition, Alternative 2 retains several components unmodified from the
original remedy:
- Off-site soil contamination
- Debris and rubble
- Wastewater treatment system
- Storage tanks and drums
- Process equipment
- Site control
EVALUATION OF THE REMEDIAL ACTION ALTERNATIVES
The following discussion presents the results of the evaluation of the nine criteria for both alternatives
currently being considered as required by CERCLA.
1. Overall Protection of Human Health and the Environment. Overall Protection of Human
Health and Environment addresses whether or not a remedy provides adequate protection and
describes how risks posed through each pathway are eliminated, reduced, or controlled through
treatment, engineering controls or institutional controls.
Both the incineration and the containment alternative provide protection of human health and the
environment by eliminating, reducing or controlling risk through treatment or capping along with
access restrictions. The containment alternative calls for covering the entire site, portions of which
contain concentrations of organics above acceptable levels. The cap/cover will act as a barrier that
restricts infiltration of storm water, release of volatile organic emissions and direct contact with the
contaminated soils.
Migration of the shallow groundwater will be mitigated with the extended barrier wall and the
groundwater recovery and treatment system. These two elements will mitigate the potential for
migration of affected groundwater to Mud Gully and eventually Clear Creek.
The on-site incineration alternative also satisfies the remedial action objectives of directly eliminating
current and future exposure to the contaminated materials at the site. Contaminated soils and
material above action levels would be treated by the incineration process, and treated soil/ash would
be used as backfill for the site.
12
-------
Both alternatives would provide effective protection of human health and the environment if
implemented and supplemented with appropriate monitoring and maintenance to provide effective
long-term protection.
2. Compliance with Applicable or Relevant and Appropriate Requirements (ARARs).
Compliance with ARARs addresses whether or not a remedy will meet all of the applicable or relevant
and appropriate requirements of other Federal and State environmental statutes and/or provide
grounds for invoking a waiver. In addition to the ARARs for the original remedy listed in the 1988
ROD, this action updates the water quality criteria for Mud Gully and adds the same criteria for the
NSCZ groundwater. The containment alternative can be performed in full compliance with all
ARARs and other criteria, advisories and guidelines which are applicable or considered relevant and
appropriate. As documented in the original ROD, the incineration alternative can be performed in
full compliance with ARARs.
3. Long-Term Effectiveness and Permanence. Long-term effectiveness and permanence
refers to the magnitude of residual risk and the ability of a remedy to maintain reliable protection of
human health and the environment over time once cleanup goals have been met.
The original remedy provides for long-term effectiveness and permanence through destruction of the
site wastes above the health based level. Exposure to remaining matenals would be further isolated
through the addition of soils to achieve stormwater control. The affected groundwater would be
controlled through the use of extraction wells to prevent off-site migration. The groundwater system
would require frequent monitoring to ensure its effectiveness.
The containment alternative involves covering of affected material on the site with soils, a flexible
membrane liner and gas collection system. This combination of cover systems will effectively reduce
exposure to site contaminants. The gas collection layer will reduce any accumulation of gases that
could damage the flexible liner and escape to the atmosphere. A current assessment of barrier
systems found that the service life of caps was uncertain, but a cap with an HDPE geomembrane may
perform satisfactorily for several hundred years. Long-term monitoring and maintenance will be
required to achieve protectiveness of the remedy.
4. Reduction of Toxicity, Mobility, or Volume Through Treatment. Reduction of toxicity,
mobility, or volume through treatment is the anticipated performance of the treatment technologies
that may be employed in a remedy.
The containment alternative does not provide reduction of toxicity, mobility or volume since
treatment of the contaminated media is not conducted as the major component of the remedy. The
alternative does provide some reduction of toxicity, mobility and volume for the components of
groundwater extraction and treatment, as well as the gas collection and treatment component of the
cap, although the volumes would be expected to be insignificant in comparison to the total mass of
contaminants at the site.
Incineration would result in a reduction of the toxicity, mobility, and volume of contaminated media
13
-------
through the destruction of the organic compounds above the health based criteria. The original
remedy would also achieve reductions for groundwater extraction and treatment, and would likely
address a larger volume of groundwater due to the additional pumping that would be required in
absence of a barrier wall.
5. Short-Term Effectiveness. Short-term effectiveness refers to the speed with which the
remedy achieves protection, as well as the remedy's potential to create adverse impacts on human
health and the environment that may result during the construction and implementation period.
The primary short-term risk for both the containment and incineration alternative is the fact that some
increase in air emissions may occur because of excavation and related intrusive activities. Emissions
from the site have been documented even in an undisturbed state. The incineration alternative would
involve significantly more intrusive activities in areas likely to contain the highest levels of
contamination, thus the potential for releases would be the highest.
The implementation time for containment is similai to that estimated for incineration, four years.
Both remedies require a significant design stage to develop the plans for implementation.
Containment will require a field investigation effort to define the limits for the vertical barrier wall.
Incineration requires approximately one year for construction.
Engineering controls and monitoring will reduce the potential for any adverse impacts during
implementation of either remedy; however, the likelihood of emission release increases with intrusive
activities despite the application of engineering controls. A contingency plan would be developed to
address any potential air emissions during remedial activities.
6. Implementability. Implementability is the technical and administrative feasibility of a
remedy, including the availability of materials and services needed to implement the chosen solution.
Both alternatives have been demonstrated at other sites to be implementable. Availability of services
to implement the alternatives is not expected to be a problem.
Difficulties with installation of the barrier wall as part of the containment alternative may arise in the
area of Mud Gully and may require innovative design. Additionally, extension of the barrier wall
across Dixie Farm Road will require extra coordination with the local communities for traffic
concerns.
As discussed above, implementibility of the incineration alternative at this site is complicated by the
likelihood of emissions due to highly intrusive activities. The incineration alternative and the
associated intrusive activities would require stringent monitoring and controls to ensure that action
levels for air emissions are not exceeded. Incineration is a complex technology that requires a
significant amount of testing prior to utilization. An incinerator was previously mobilized to the site,
however, wastes were never introduced and testing was not conducted. Excavation of wastes for
incineration required the use of stringent engineering controls, although emissions from the
excavations were still detected at the fence line of the site.
14
-------
7. Cost. Cost includes an evaluation of capital cost and the cost of operation of the remedy in
the present worth calculation.
Alternative 1 - Incineration
The estimated cost of this alternative in the 1988 ROD was $21.6 million. Bids received for the
remedy revised the estimate to over $40 million. The current estimate of the incineration remedy was
derived from the actual bid received on the original remedy with an escalation figure applied. The
net present worth of implementing this remedy is $77.5 million. The capital cost is $61.4 million.
Components for Alternative 1
Incineration
Design and Testing
Construction, demobilization
Operation
Emission Control
Construction Oversight
Operations Oversight
Construction Contingency
NSCZ Groundwater Recovery
Mud Gully Channel
Improvements
Ground Water Treatment
System
DNAPL Separation and
Disposal
Fencing and Site Security
Equipment Dismantling
NSCZ Groundwater Monitoring
FFSZ Groundwater Monitoring
Mud Gully Monitoring
Site Management
Total
Capital costs
$1,180,000
$9,240,000
S>3 1,920,000
$3,000,000
$1,000,000
$2,000,000
$7,250,000
$911,000
$2,540,000
$1,100,000
$87,300
$377,500
$460,000
$78,750
$34,000
$0
$230,000
$61,408,550
30 year
Present
Worth
$1,180,000
$9,240,000
$31,920,000
$3,000,000
$1,000,000
$2,000,000
$7,250,000
$2,970,000
$2,540,000
$8,400,000
$660,000
$460,000
$460,000
$530,000
$280,000
$100,000
$5,520,000
$77,510,030
15
-------
Alternative 2 - Containment
The estimated cost of implementing the Containment remedy is $42.7 million net present worth. The
net present worth assumes 30 years of operations for calculation purposes. The capital cost of the
remedy is $22.7 million.
Components for Alternative 2
Containment
Subgrade Barrier Wall
NSCZ Groundwater Recovery
Surface Tar Delineation
Cap System
Mud Gully Channel
Improvements
Ground Water Treatment
System
DNAPL Separation and
Disposal
Vapor Recovery Operations
Fencing and Site Security
Equipment Dismantling
Air Monitoring
NSCZ Groundwater Monitoring
FFSZ Groundwater Monitoring
Mud Gully Monitoring
Site Management
Total
Capital costs
$4,305,600
$911,000
$280,000
$12,305,000
$2,540,000
$1,100,000
$87,300
$0
$377,500
$460,000
$0
$78,750
$34,000
$0
$230,000
$22,709,150
30 year
Present
Worth
$4,310,000
$2,970,000
$280,000
$13,100,000
$2,540,000
$8,400,000
$660,000
$500,000
$460,000
$460,000
$2,600,000
$530,000
$280,000
$100,000
$5,520,000
$42,710,000
8. State Acceptance. State Acceptance indicates whether, based on its review of the RI/FS and
ROD, the State concurs with, opposes, or has no comment on the selected alternative.
The Texas Natural Resource Conservation Commission (TNRCC) has been provided a draft copy
16
-------
of this ROD and the TNRCC has participated throughout the process in working with the CAG. The
TNRCC concurs with the containment remedy.
9. Community Acceptance. Community Acceptance has been assessed in the Record of
Decision following a review of the public comments received on the RI/FS report and the Proposed
Plan.
The community has strongly opposed implementation of the incineration remedy in the past. The
conimunity's opposition was instrumental in this re-evaluation of the remedy. EPA chartered the
CAG in September 1994 to assist with the development of a remedy for the site, and the CAG had
significant input in the development of the containment remedy. The CAG supports the new
proposed remedy.
SUMMARY OF THE SELECTED REMEDIAL ALTERNATIVE
The new selected remedial alternative is the containment alternative with volatile organic chemical
(VOC) and groundwater recovery which is composed of several components that together will
provide a long-term solution that is reliable and protective of human health and the environment.
alternative. The individual components of the selected approach are described below. As discussed
above, certain elements of the original ROD are not affected by this ROD Amendment.
1. Containment System
This amended Record of Decision (ROD) revises the original remedial action for treatment
of affected materials, soils and surface contamination to installation and long-term maintenance of a
containment system. The containment system will be designed, constructed and operated to recover
VOCs and limit the migration of site contaminants to the air, soil and groundwater to concentrations
that are fully protective of human health and the environment. The containment system will consist
of the following principal elements:
A. Vertical Barrier Wall
To limit the potential for off-site migration of affected soil and groundwater, a
continuous1 vertical barrier wall, keyed or grouted into the Middle Clay Unit, shall be constructed.
The vertical barrier wall will extend into the Southbend Subdivision to the north of the site and east
of Pit Q and south to the pipeline corridor. The area to be enclosed by the vertical barrier wall is
conceptually shown in Figure 2. As part of the Remedial Design phase, materials of construction and
types of commercially available barrier walls (e.g., slurry, composite slurry, scalable joint sheet pile,
deep soil mixing, vibrated beam and soil saw technology) will be evaluated. The barrier wall selected
1 There will be some discontinuity in the areas of roads, buried pipelines or other obstructions.
17
-------
shall be designed and constructed to achieve long term reliability by maintaining structural integrity.
resistance to chemical corrosion and designed to meet a 10"7 cm/sec hydraulic conductivity. The
selection process will also consider ease of constaiction. and minimization of community disruption,
including potential emissions.
B. Site Cover
To further control potential air emissions from the site, minimize to the extent
practicable surface water infiltration and to minimize to the extent practicable the migration of site
contaminants into the groundwater, a composite cap shall be constructed to cover the areas shown
in Figure 2. The composite cap will be multilayered and consist of a bedding layer of soil to achieve
slope for moisture control in the gas collection layer, a gas collection layer, a flexible membrane liner,
a minimum of one and one-half feet of compacted clay, top soil and vegetative cover. (This
minimum clay thickness may be reduced in the capped portions of Southbend as well as in drainage
conveyance areas.) The liner material will be selected during the remedial design. The cap system
( clay cover plus liner) shall achieve a hydraulic conductivity of 10'7 cm/sec.
C. Gas Collection
To recover VOCs and provide reliable long term control of VOCs, in addition to the
flexible membrane liner, a gas collection layer will be a component of the site-wide cap. The cap will
be divided into compartments, based on water runoff considerations and the relationship to former
pit areas. The cap installed over each compartment will have a gas collection layer and a vent
system leading from the gas collection layer to the surface. The vent system shall be vacuum assisted.
A minimum vacuum requirement shall be determined for the piping system during the
operational mode to ensure optimal recovery of VOCs and that collected vapors are effectively routed
by vacuum or the blower to the treatment system. The vacuum requirement and the sizing of the
treatment system will be established during a pre-operations study of the gas collection layer after
construction of the cap is complete. The vent system shall be monitored to ensure against vapor
build-up within the gas collection layer.
The vent system shall be manifolded to a treatment system(s). The treatment system(s)
shall, at a minimum, consist of two carbon units in series. The air flow between the two carbon units
shall be monitored, initially daily. Breakthrough will be defined as a reading of 50 ppm VOCs, in
which case the spent carbon unit will be replaced by a fresh unit within 12 hours. After startup, the
monitoring frequency between the two carbon units shall be adjusted to a time period no greater than
one tenth (1/10) the expected carbon life.
An initial baseline monitoring of total VOC production on a compartment by
compartment basis shall be carried out once the system is operational. The baseline monitoring will
18
-------
-------
consist of 1 sample and flow measurement per month of total VOCs, per compartment, for a
minimum of 12 consecutive months. The amounts and types of VOCs recovered shall be reported.
Prior to any compartment(s) being closed off, 12 months of such data shall be presented supporting
the closing. (The initial baseline data may be used for this purpose.) For those compartments which
are valved off, a maximum pressure will be defined during design to determine when the closed off
compartment must be reopened to the treatment system.
If the amount of VOCs in the air flow to the treatment system results in breakthrough of the
carbon units occurring more frequently than once (1) every ten (10) days, then a study evaluating the
efficiency of the VOC recovery and treatment system shall be prepared. This study will evaluate: (1)
changing the treatment capacity/method, or (2) increasing VOC recovery through installation of
vertical wells, whichever better optimizes VOC recovery. This study will consider value engineering
concepts, cost effectiveness, safety, VOC recovery rates, and the short term and long term potential
for creating emissions in the optimization analysis.
D. Groundwater Flow Control fNoCZ)
To limit the migration of site contaminants from within the containment system, a
groundwater pumping system shall be constructed that will collect groundwater from the NSCZ
inside the vertical barrier wall to ensure that contaminant concentrations outside the vertical barrier
wall are protective of human health and the environment. An inward gradient shall be maintained
within the barrier wall in areas of plume contamination. Performance of the groundwater flow
control system shall be demonstrated through measurement of groundwater levels within the barrier
wall and flow rates into the pumping system, as well as monitoring concentrations of contaminants
outside the vertical barrier wall on the down-gradient side. Annual reports shall be provided on the
effectiveness of the system and the amounts of groundwater pumped from the site. The groundwater
pumping system will be operated continuously or intermittently as long as necessary in order to
maintain inward hydraulic gradient.
E. Groundwater Treatment
Groundwater that is recovered through the pumping system shall be treated on-site
and discharged off-site into Mud Gully. Recovered groundwater shall be treated to meet relevant
standards within the receiving water.
2. Air Monitoring
To protect public health, an air monitoring system shall be maintained during
construction of the remedy. The system shall be designed to detect organic site contaminants at levels
sufficient to prevent harm to persons living or working in the surrounding community. Action levels
for the air monitoring system shall be specified in the Scope of Work. EPA will establish these action
levels, after consultation with ATSDR and the Texas Department of Health, taking into account
conditions now existing at the site and within the surrounding community.
20
-------
3. Long Term Groundwater Monitoring
A five-well monitoring system shall be maintained in the FFSZ. The wells shall be
screened in the upper portion of the FFSZ. The monitoring program shall require volatile organic
compound and semi-volatile organic compound samples to be collected semiannually, using standard
EPA laboratory methods for testing drinking water. For each well, if no monitored compounds are
detected above MCLs2 for a period of five years, subsequent monitoring of that well shall take place
annually. If the same monitored compound is detected above MCLs in a well for two consecutive
monitoring periods, a report shall be within sixty (60) days prepared evaluating the likely cause for
the presence of the compound and proposing relevant responsive actions.
If all wells in the monitoring system achieve annual monitoring status and for a period
of five consecutive years the annual monitoring results show no monitored compounds above MCLs,
a petition may be submitted for EPA review which shall describe the performance of the monitoring
system and request approval to modify or terminate the monitoring program.
Water Quality Criteria are established for contaminated groundwater in the NSCZ
outside the vertical barrier wall and monitoring shall be conducted in the NSCZ in order to
demonstrate compliance with the criteria. Treatment will be required for this groundwater only if
concentrations exceed the criteria.
4. Site Maintenance and Control
The amended remedial action continues to be based on maintaining permanent site
control that restricts access to the site by means of a fence or similar barrier. The property within the
restricted area shall be graded to allow storm water to drain toward Mud Gully. The site cover shall
be landscaped with hardy grasses well suited to the local climate.
5. Mud Gullv
Except in the event of Mud Gully relocation, channel improvements shall be installed
in the section of Mud Gully immediately adjacent to Brio North. These improvements shall consist
of a concrete lined channel that will ensure that the hydraulic flow capabilities of this section of Mud
Gully are consistent with the areas of the gully immediately upstream and downstream of this section.
Surface water quality testing will be conducted quarterly to monitor compliance with water quality
standards if such improvements are made.
EPA recognizes that in response to community input, Harris County or the Harris
County Flood Control may relocate Mud Gully such that it no longer runs adjacent to the site. If
Harris County or the Harris County Flood Control has made a firm commitment to relocate Mud
'For monitored compounds where the MCL is below the Practical Quantitation Limit (PQL), the relevant detection
limit shall be the PQL.
21
-------
Gully prior to design activities, then the channel improvements portions of this remedial action will
not be required. The schedule for implementing the cover portion of the remedy shall be staged
accordingly to take advantage of any excess fill material make available by the relocation. If a timely
commitment to relocation is not made by Harris County or the Harris County Flood Control, the
channel improvements will continue to be required.
6. Public Participation
EPA recognizes the significant role community input and support have played in
reaching this amended remedial decision. EPA will continue to seek active community input and
involvement during the design and implementation phases of the remedial action. EPA plans to
continue to maintain a community outreach office in the local community. The EPA shall continue
to maintain a document depository at the local community college until NPL deletion, or until five
years after completion of the Remedial Action phase, whichever is sooner. All major deliverables
under this amended ROD shall be made available in both the EPA community office and the local
repository to allow an adequate opportunity for community review and comment prior to final EPA
approval. Copies of all major deliverable documents during the Operational and Maintenance phase
of this remedy, shall also be supplied to a chosen repository.
STATUTORY DETERMINATIONS
Under CERCLA section 121, EPA must select remedies that are protective of human health and the
environment, comply with applicable or relevant and appropriate requirements (unless a statutory
waiver is justified), are cost-effective, and utilize permanent solutions and alternative treatment
technologies or resource recovery technologies to the maximum extent practicable. In addition,
CERCLA includes a preference for remedies that employ treatment that permanently and significantly
reduce the volume, toxicity, or mobility of hazardous wastes as their principal element. The following
sections discuss how the selected remedy meets these statutory requirements.
Protection of Human Health and the Environment
The selected remedy protects human health and the environment by eliminating, reducing or
controlling risk through containment along with access restrictions. The containment technologies
include a sub-grade vertical barrier wall, a cap system that includes a compacted clay layer, a liner,
and a gas collection system, and groundwater flow controls. Contaminants will be removed from the
site via the groundwater collection system and the gas collection system in addition to the existing
dense non-aqueous phase liquid extraction program. The cap/cover will act as a barrier that restricts
infiltration of storm water, release of volatile organic emissions and direct contact with the
contaminated soils. The containment remedy will require periodic maintenance to ensure its
effectiveness.
Migration of the shallow groundwater will be mitigated with the extended barrier wall and the
groundwater recovery and treatment system. These two elements will mitigate the potential for
migration of affected groundwater to Mud Gully and eventually Clear Creek.
22
-------
Compliance with Applicable or Relevant and Appropriate Requirements
The selected remedy of subgrade vertical barrier wall, cover with gas collection system, and
groundwater flow control will comply with all applicable or relevant and appropriate requirements
(ARARs). The 1988 ROD identified ARARs for the site and the cap and cover alternative. ARARs
in addition to those identified in the original Record of Decision are presented below. Any numerical
criteria that have been modified in the existing ARARs since the 1988 ROD will be updated.
Chemical-specific ARARs:
• Texas Surface Water Quality Standards, TAG §307
• Risk Reduction Standards, Texas Water Code, Subchapter S
Location-specific ARARs:
None
Action-specific ARARs:
• 30 TAG Chapter 116, Standard Exemption 118, Standard Exemption 68
Cost-Effectiveness
EPA believes this remedy will eliminate the risks to human health at an estimated cost of $22.7
million. The selected remedy assures a much higher degree of certainty that the remedy will be
implemented without short-term risks due to volatile emission releases inherent in intrusive remedies.
The cost of the selected remedy of containment is less dependant on a variation of quantity of wastes
that could significantly impact a remedy such as incineration.
Utilization of Permanent Solutions and Alternative Treatment Technologies for Resource Recovery
Technologies) to the Maximum Extent Practicable and Preference for Treatment as a Principal
Element
The principal threats at the site are discharges of contaminated groundwater to surface water, air
emissions from on-site wastes, and direct contact with on-site wastes. The sources of contamination
to these pathways include the presence of DNAPL in the NSCZ and pit residuals located in the near
surface.
The remedy contains several treatment components while addressing the principal threats at the site.
The discharge of contaminated groundwater is restricted by the installation of a sub-grade barrier
wall, and groundwater pump and treat will be utilized in conjunction with the barrier wall to assist
in the containment of the contaminated groundwater. The barrier wall is dependant on a treatment
component (i.e. groundwater pump and treat) for long-term effectiveness. The air pathway is
23
-------
addressed through the gas collection layer. This component utilizes treatment of the contaminants
in the gas collection layer via carbon adsorption (or other absorptive media) followed by off-site
incineration of the carbon. In addition, the extraction and treatment (off-site incineration) of the
DNAPL remains a component of the remedial action for the site.
The amended remedy does provide for significantly less treatment than the original remedy. Inclusion
of treatment to a greater degree would require more intrusive activities that could result in higher air
emissions. The community is adamantly opposed to any remedy that would increase the risk of short-
term air emissions from the site.
DOCUMENTATION OF SIGNIFICANT CHANGES
The Proposed Plan for the Brio site was released for public comment on April 4, 1997. The Proposed
Plan identified Containment as the preferred alternative. EPA reviewed all written and verbal
comments submitted during the public comment period. Upon review of these comments, it was
determined that no significant changes to the remedy, as originally identified in the Proposed Plan,
were necessary.
A modification to Table 2 (Revised Surface Water Criteria) was required following input from the
TNRCC. The Mud Gully criteria was modified to accurately reflect the identified standards submitted
by the TNRCC on February 27, 1997. In addition, a change in the criteria utilized as the most
protective standard was made. For 12- dichloroethane it was noted by TNRCC that the human health
criteria was now higher than the fresh water quality criteria because the adjustment factor of one
hundred (100) times the criteria for Clear Creek has changed from the original factor often (10).
Due to this change, the human health criteria was no longer the most protective and the fresh water
quality criteria should be used. The ROD is modified to reflect this change.
24
-------
BRIO REFINING SUPERFUND SITE
HOUSTON, TEXAS
AMENDED RECORD OF DECISION
RESPONSIVENESS SUMMARY
This Responsiveness Summary is prepared from written and oral comments received during the
public comment period on the Proposed Plan. The comment period ran from April 7, 1997,
through May 7, 1997. Less than ten written comment letters were received. The letters were
supportive of the proposed remedy.
A public meeting was held on April 15, 1997, at the San Jacinto College, South Campus.
Approximately 40 people attended the meeting. Nine people provided comment during the
meeting. A transcript of the meeting was prepared. Written comments and the transcript are part
of the amended Administrative Record.
Summary of Maior Comments Received
1. Comment - The Brio-CAG's support of the plan is based on the assumption that all of the
critically important language on the Preferred Remedial Alternative in the Proposed Plan will
remain without changes in the final ROD.
Response: As stated in the ROD's Documentation of Significant Changes, no
significant changes to the proposed alternative were necessary as a result of public comments
received.
2. Comment - The Brio-CAG's support for the plan is contingent on EPA providing
continued funding for its TAG so that the Brio-CAG can remain engaged in the remedial design
and remedial action phases of the cleanup. The national Superfund Ombudsman should remain
involved at the site.
Response: Two technical assistance grants have already been awarded at the Brio site
totaling $100,000. Future grants will require a waiver from EPA headquarters, and this issue is
currently under review by headquarters. The national Superfund Ombudsman is expected to have
continued involvement with the Brio site.
3. Comment - The Brio-CAG strongly supports the inclusion of the described gas collection
component of the preferred remedial alternative. The gas collection component should be fully
implemented and used to the maximum extent practical to remove VOCs which if not removed
would pose a long term public health threat to the community.
Response: The gas collection system described in the proposed plan remains a
component of the selected remedy. The system will be fully implemented during the remedial
action and operated at an optimal rate to ensure recovery of VOCs and effective collection and
-------
treatment. However, the gas collection layer is not intended as a treatment remedy for the
contaminated soils.
4. Comment - The ROD should present more information concerning the 1994 SRO Report,
particularly with regards to dioxin testing. Any future subsurface soil testing for construction of
the remedy should include dioxin testing.
Response: The 1994 SRO Report is included in the Administrative Record and does
not require further discussion in the ROD. The inclusion of the recommendation to do dioxin
testing in the SRO Report was based on addressing community concerns with the incineration
remedy. There is no technical basis to use dioxin testing to guide the construction of the
containment remedy as all contaminants will be addressed by the cap.
5. Comment - The ROD should discuss findings of the flux tests in direct support of the gas
collection component of the preferred alternative.
Response: The flux testing reports are included in the Administrative Record and were
considered in the decision making process for the ROD.
6. Comment - The ROD should contain more explanation for extending the containment
remedy into the Southbend Subdivision.
Response: The purpose of the vertical barrier wall is to limit the potential of
migration of affected groundwater. The vertical barrier wall extends into the former Southbend
Subdivision to address the presence of contaminated groundwater. Sampling data to support the
conceptual location of the cap and barrier wall is contained in the Administrative Record. The
exact location of the vertical barrier wall will be determined in the Remedial Design.
7. Comment - The ROD should provide additional detail regarding emission problems during
the previous remedy.
Response: Information concerning emissions during implementation of the
incineration remedy is documented in the Administrative Record. This information was
considered during the decision making process for the ROD.
8. Comment - Due to uncertainty about the exact amount of the contaminants at the site,
EPA should re-consider the statement that insignificant volumes of contaminants would be
removed through treatment.
Response: EPA bases its analysis on current estimates of the mass of contaminants
shown to be present at the site and the expected efficiency of removal of mass through a pump
and treat system or collection of VOC vapors. Based on these estimates, EPA believes that its
statement is correct.
9. Comment - EPA should discuss the importance of the gas collection component under the
-------
evaluation of long-term effectiveness and permanence.
Response: A discussion of the gas collection component has been included under the
evaluation of long-term effectiveness and permanence.
10. Comment - The re-routing of Mud Gully should be expedited so that it no longer flows
through the site.
Response: If the project is undertaken by Harris County, the timing of the re-routing
will be determined in the remedial design. Several steps are required for the relocation, such as an
engineering evaluation and the securing of right of way, before the construction of the re-routing
could begin by the county.
11. Comment - Expand the remedial design to include an evaluation of the sections of Clear
Creek downstream of site to determine the extent and degree of contamination.
Response: Considerable testing has been conducted in Clear Creek to date by EPA
and various state and local agencies. A health consultation was prepared by the Agency for Toxic
Substances and Disease Registry stating that the level of contaminants found does not pose a
human health risk. Additional testing of Clear Creek is not necessary based on previous sampling
and further information is not required to provide an adequate characterization of risk.
12. Comment - Provide a funding mechanism to cover the increased costs associated with
future Clear Creek projects that involve contact with and/or reintrainment of the contaminated
sediments.
Response: EPA's use of the Superfund is governed by CERCLA and its implementing
regulations. The suggested funding mechanism would not be appropriate pursuant to these
authorities.
13. Comment - The community should be educated of the hazards of the buried chemical at
the site. The best remedy for the site is containment.
Response: The EPA will continue meeting with the Brio Community Advisory Group
throughout the implementation of the remedy. The CAG meetings are open to the public and are
an excellent source of information regarding the status of site operations as well as an educational
opportunity regarding site hazards. EPA also maintains a local community relations office that
focuses on providing citizens with information regarding the site. Also, a repository will be
maintained near the site that will contain the Administrative Record for the site.
14. Comment - Will the liner in the cap degrade over time? A rubber or hard plastic layer
should be used that will not deteriorate.
Response: Compatibility testing will be done as part of the remedial design to ensure
that the best material is selected for the site. The most common type of liner, a high density
-------
polyethylene (HPDE) liner, is expected to perform for several hundred years.
15. Comment - The BSTF supports the installation of the remedy set forth in the Proposed
Plan, including the site-wide gas collection cap. It is the BSTF position that the performance of
this cap be judged on how well it prevents emissions to the atmosphere, and not on the amount of
volatile organic emissions recovered.
Response: EPA agrees that the primary function of the gas collection layer is to
prevent emissions to the atmosphere, however, this can only be achieved through the removal of
volatile organics that would otherwise be released to the surface. The gas collection layer will be
operated in a manner that achieves optimal recovery. Optimal recovery will be defined by
considering value engineering concepts, cost effectiveness, safety, VOC recovery rates, and the
short and long term potential for creating emissions. The gas collection layer is not intended as a
treatment remedy for the contaminated soils.
16. Comment - The revised Water Criteria lyr Mud Gully should apply to NSCZ groundwater
outside of the barrier wall unless the BSTF shows (by modeling or other means) that alternate
NSCZ action levels are protective of surface water criteria. There is an error in Table 2 in the
Proposed Plan.
Response: For contaminated ground waters that discharge to surface water, Water
Quality Criteria established under the Clean Water Act, or more stringent State surface water
requirements, may also be cleanup level ARARs (Fed. Reg., 1990, Preamble at 8754),[NCP,
300.430(e)(2)(I)(E)]. The application of the Water Criteria as a remediation level for the NSCZ
is directly applied to the groundwater, using the groundwater as the point of compliance, not just
the receiving surface water body. "For ground water, remediation levels should generally be
attained throughout the contaminated plume, or at and beyond the edge of the waste management
area when waste is left in place" (Fed. Reg., 1990, Preamble at 8713). Waste will be left in place
at the Brio site. The edge of the waste management area would be considered the vertical barrier
wall.
17. Comment - The former storage pit areas should not be referred to as "disposal areas".
This is not an accurate description of the prior use of these units.
Response: Although the pit areas were originally intended as storage areas, many
became disposal areas when the stored product was not fully utilized or partially left in place
during close out of the pits. Both terms are appropriate.
18. Comment - EPA states that air monitoring showed that fugitive emissions could leave the
site even in an undisturbed state. It is important to point out that these emissions have been
evaluated by EPA and the Agency for Toxic Substances and Disease Registry and were found to
not present a threat to human health and the environment.
Response: The statement in the ROD concerning fugitive emissions is included to
support the conclusion that intrusive activities on site (on-site incineration) would present a short-
-------
term threat during implementation, because emissions occur even in an undisturbed state. The
ROD does not attempt to support taking an action solely on the current level of the emissions.
Therefore, a discussion of the human health threat posed by such emissions is not warranted.
19. Comment - The description of the composite cap should be clarified in the text to note
that the cap will not be installed to the limits of the barrier wall over DOP South.
Response: The text has been modified to incorporate this comment.
-------
Bury R. McBw,
^? JlfN ?7 PH L: ?
TEXAS NATURAL RESOURCE CONSERVATION COMMISSIONI-RFUNO mv.
fnlectifig TauK&ffteducinffamtPtwmffm) t-CTOR 5 OFC.
June 2€,
VIA OVERNIGHT MAIL
Myron O. Knndson, P,&» Director
Superfiind Division
U.S. Environmental Protection Agency
Region 6
1445 Ross Avenue
Dallas, TX 75202-2733
Re: Brio Refining Superfund Site
Amended Record of Decision
Dear Mr. Knudson:
The Texas Natural Resource Conservation Commission concurs with the Amended Record of
Decision (ROD) for the Brio Refining Superfumt Site, as. presented in the draft ROD received
May 30,1997.
Please contact Mr. Ashty McMullan, Superiund En^ncering Project Manager, at (512) 239-2595
for any additional information concerning the site.
Sincerely,
tor
P.O. Box 13087 • Austin. T««.7$711-3087 • 512X219-1000 • Internet id*«S;
------- |