EPA/ROD/R09-95/139
August 1995
EPA Superfund
Record of Decision;
Louisiana-Pacific
Qroville, CA
8/1/95
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RECORD OF DECISION
LOUISIANA-PACIFIC SUPERFUND SITE
OROVILLE, CALIFORNIA
U.S. Environmental Protection Agency
Region 9
San Francisco, California
August 1995
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LOUISIANA-PACIFIC SUPERFUND SITE
RECORD OF DECISION
. Table of Contents
Section.
Page
. I. DECLARATION
IT. DECISION SUMMARY
1.0 SITE NAME, LOCATION, AND DESCRIPTION
5.1 Soils
5.2 Groundwater
5.2.1 Arsenic in Groundwater
5.2.2 Formaldehyde in Groundwater
1
5
6
6.
7
8
8
9
11
11
12
12
12
13 ~-/
13
13
13
2.0 SITE HISTORY AND ENFORCEMENT
3.0 COMMUNITY PARTICIPATION
4.0 SCOPE AND ROLE OF DECISION
5.0 SUMMARY OF SITE CHARACTERISTICS
6.0 SUMMARY OF SITE RISKS
6.1 Risk from Exposure to Shallow Groundwater
6.1.1 Formaldehyde
6.1.2 Arsenic -
6.2 Risk from Exposure to Regional Groundwater
6.3 Risk from Exposure to Surface Soil
7.0 DESCRIPTION OF THE NO ACTION ALTERNATIVE
8.0 EXPLANATION OF SIGNIFICANT CHANGES
ITI. RESPONSE SUMMARY
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Table
5-1
Figure
1-1
1-2
1-3
5-1
5-2
LIST OF TABLES
Page
Summary of Contaminant Concentrations in Groundwater and Soil
9
LIST OF FIGURES
Page
Site Location Map
1
L-P Plant Features
'"
L.
L- P Landfill Features
3
Koppers Plume Area
8
Cross Section Displaying the Shallow Aquifer, Aquitard and
Regional Aquifer
10
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I. DECLARATION
SITE NAME AND LOCATION
Louisiana-Pacific Corporation
Oroville,. California
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected final remedial action for the Louisiana-
Pacific (L-P) site in Oroville, California, which was chosen in accordance with the
Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), as
amended by the Superfund Amendments and Reauthorization Act (SARA), and, to the extent
practicable, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP).
This decision is based on the administrative record for this site.
The State of California concurs with the selected remedy.
DESCRIPTION OF THE SELECTED REMEDY: NO ACTION
The selected remedy is no further remedial action. The results from soil sampling and
groundwater monitoring conducted since the 1990 Interim Record of Decision indicate that
the low levels of contamination at the site do not pose a significant risk to either public health
or the environment. The institutional controls selected in the 1990 Interim Record of
Decision are no longer necessary, and no further monitoring is required.
DECLARATION.
No remedial action is necessary to ensure protection of human health and the
environment. A five-year review is not required pursuant to Section 121(c) of CERCLA.
EP A has determined that its response at this site is complete. Therefore, the site now
qualifies for inclusion on the Construction Completion List. .
AUG 0 1 1995
. Date
1X:HVl ~Icar---
Keith Takata .
Deputy Director for Superfund
Hazardous Waste Management Division
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n. DECISION SUMMARY
1.0 SITE NAME, LOCATION, AND DESCRIPTION
The Louisiana-Pacific (L-P) site consists of a wood processing plant and landfill
located in Butte County just south of the city limits of Oroville, California (population
10,560) (see Figure 1-1, Site Location Map). Log storage, lumber production, and hardboard
manufacturing take place at the plant. Disposal of wood wastes takes place at the landfill.
The plant and landfill are located about 1/2 mile apart and are separated by the Koppers
Company, Inc., Superfund site, which is also on the EPA's National Priorities List. Features
of the L-P plant and landfill are shown in Figures 1-2 and 1-3, respectively.
The L-P plant lies in the Feather River floodplain at an elevation of about 145 feet
above mean sea level in an area of tailings piles created by dredger mining activities that
ceased around 1936. The northern part of the plant is occupied by buildings and paved with
asphalt. The central part of the plant has been graded relatively level for log storage. The
western margin and southwest corner of the plant retain much of the historic, irregular
dredge-tailing topography since modified by quarrying for log-deck base material.
The Feather River is located about 1/2 mile west of the plant at an elevation of 120
feet above sea level. The Feather River floodplain extends from the river to the Baggett-
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Figure 1-2. L -P plant features
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. EXPLANATION
rit~~I~ttt Area of Concern
Figure 1-3. L-P Landfill features
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Marysville Road (south and east of the L-P plant - see Figure 1-1) where it ends at a
prominent bluff eroded into hills and ravines. The bluff rises 100 to 170 feet above the
floodplain to meet the gently rolling upland extending to the south and east.
The landfill operation has filled one of the ravines in the eroded bluff. The effect of
the landfill has been the formation of a nearly flat ridge at an elevation of 270 feet where the
ravine once was located.
Surface water run-off flows westward from the L-P landf1l1 onto the .Koppers site and
then into the log deck pond at the southeast comer of the L-P plant. Plant drainage flows
generally south into the log deck pond but is complicated by closed drainages where run-off
inf1ltrates to groundwater. Drainage from the log deck pond flows through a chain of three
ponds immediately south of the L-P plant boundary, and then west to gravel pit ponds nearer
the Feather River.
. .
The L-P plant is underlain by two aquifers and an intervening clay aquitard. The
shallow aquifer that exists beneath the plant extends from ground surface to depths of 20 to
40 feet. This aquifer is not present in the undredged areas at the adjacent Koppers site.
Although the shallow aquifer probably existed prior to L-P plant operations, present water
levels are higher than would naturally occur due to the sprinkler application of water to the
log deck. The permeability of the shallow aquifer varies considerably laterally across the
plant. Groundwater in the shallow aquifer appears to move both north and west away from
the recharge areas created by the ponds, the boundary ditch and the almost continuous
sprinkler irrigation of the log deck. This aquifer is not currently used as a source of water
supply.. .
. The regional aquifer extends to a depth greater than 300 feet beneath the L-P plant,
and is also present beneath the Koppers site and the L-P landfill. Groundwater movement in
the regional aquifer is generally to the south. This aquifer serves as a current source of .
drinking water. .
The entire L-P plant is underlain by dredge tailings deposited during gold mining
operations in the earl)' 1900s. The tailings consist of unsorted cobble, gravel, sand, silt and
clay derived from dredging of the floodplain alluvium. The dredge tailings, which may be as
deep as 30 to 45 feet, constitute the shallow aquifer. Beneath the dredge tailings lies older
alluvium of similar composition that was deposited by the ancestral Feather River and
constitutes an aquifer of regional extent.
Land use in the vicinity of the site is mixed agricultural, residential, commercial, and
industrial. One- to five-acre farms exist, and much of the produce and livestock is raised for
home use and not sold commercially. Residential areas are located to the south, southeast,
west, and northeast of the site. Three schools are located within a two-mile radius of the site.
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2.0 SITE HISTORY AND ENFORCEMENT
Dredge mining for gold in the Feather River basin began around the turn of the
century~ The Louisiana-Pacific plant area and environs rest on tailings created by the dredger
mining activities. In 1929, a San Francisco-based mining firm, Natomas Company, purchased
the land around the present L-P site from several individuals, and continued dredge operations
until 1936. At that time, Butte County issued regulations requiring replacement of topsoil.
From 1936 until 1969, no organized dredging activity occurred at the L-P plant area or
environs. Georgia-Pacific Corporation purchased the present L-P site in 1969 and completed
construction of the sawmill facility in 1970. Louisiana-Pacific Corporation took control of
the property in 1973. The hardboard facility was constructed in 1973, and L-P began'
operations at the landfill in 1978.' .
. .
. ,
. Between 1970 and .1984, L-P used a fungicide spray containing pentachlorophenol
(PCP) to prevent fungal discoloration of sawn lumber.. In 1973,'a state agency discovered
PCP contamination in' local groundwater south of the L-P plant. . Since 1973, state agencies
have monitored the L-P site, and have detected PCP contamination in surface water, sawdust,
and wood waste at the plant and landfill. As a result of this evidence and L-P's use of PCP,
L-P was suspected of being partly responsible for the PCP contamination discovered in 1984
in groundwater south o~ the adjacent Koppers site.
In May 1985, the California Department of Health Services requested that EP A take
over as lead agency at the L-P site. In February '1986, the L-P site was placed on EP A's.
National Priorities List (NPL). In December 1986, following unsuccessful RIfFS negotiations
with L-P, EP A began remedial investigations of surface water, soil, sediment, groundwater,
. wood waste, and air at the L-P site for evidence of contaminants; EPA issued a Remedial
Investigation (RI) Report in January 1989. Concurrent investigations of air quality were
conducted by L-P and the Butte County Air Pollution Control District over a one-year period
beginning in 1988. An Endangerment Assessment Report on risks from the L-P site was
issued by EPA in September 1989, and a Feasibility Study (FS)Report was issued in May
1990.
In September 1990, EPA issued an Interim Record of Decision for soil and
groundwater that required institutional controls as well as further' soil sampling and
groundwater monitoring. L-P conducted the required sampling and monitoring pursuant to an
administrative order issued by EPA in July 1991. EPA issued a Supplement to the
Endangerment Assessment in May 1995.
Results of the EPA and L-P investigations have shown that groundwater, surface
water, soil, sediment, and wood waste .contain various contaminants used by L-P and
Koppers. Concentrations. on the L-P plant were found to be highest in an area along the
L-P/Koppers boundary. Contaminants in this area will be addressed as part of the Koppers
cleanup. Elsewhere on the L-P plant, contaminant concentrations were not high enough to
pose a significant risk to human health or the environment.
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Although PCP was detected in surface and subsurface soils, surface waters and
groundwater at the L-P site, the concentrations were so low as not to pose a significant threat
to human health and the environment.
Correspondence between EP A and L-P can be found in the Administrative Record for
this site, an index of which is attached to this Record of Decision.
3.0 COMMUNITY PARTICIPATION
The EP A has encouraged public participation throughout the RIIFS process, in
accordance with CERCLA requirements.
Fact sheets were sent out to the public at key progress points in the investigation.
Technical exchange meetings were held monthly or bimonthly at the site during the field
work phase of the RI, with representatives of public agencies and local citizen groups invited
to attend. RIlFS documents, including the Remedial Investigation Report, the Endangerment
Assessment Report, and the Feasibility Study Report, were sent to local libraries and a
representative of a community group. Similarly, documents prepared by L-P and EPA .
following the 1990 Interim ROD also were sent to local libraries.
Public participation requirements for EP A's selection of the final remedy as defined in
CERCLA sections 113(k)(2)(B)(i-v) and 117(a) were met by the activities described below.
The proposed plan was distributed using EPA's mailing list for this site. A public
comment period on the proposed plan was held between May 20, 1995 and June 19, 1995. .
Public notice appeared in local newspapers, including the Oroville Mercury-Register~ prior. to
the opening of the public comment period, and this notice. A formal public meeting was
held on June 1, 1995. A transcript of the meeting can be found in the Administrative Record
for this site.
The attached response summary provides EP A's responses to written comments
submitted during the public comment period and to comments made during the June 1,.1995
public meeting.
4.0 SCOPE AND ROLE OF DECISION
D
Contaminant concentrations in soil and groundwater at the site do not pose a sig-
nificant risk to human health or the environment for current or future uses of the site.
Therefore, EPA is selecting no further remedial action as the final remedy at the L-P site.
The monitoring conducted over the last three years has identified low levels of
formaldehyde contamination below health-based levels of concern in the shallow groundwater
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near th~ western sump. L-P stopped discharging washwater containing formaldehyde to this
sump back in 1988. Current concentrations in shallow groundwater are believed to be due
primarily to residual formaldehyde that is slowly leaching from sump sediments into shallow
groundwater.
The w~stern or northern extent of this. contamination (or of the shallow aquifer) is not
known since there are no shallow aquifer monitoring wells off site. Results from recent
sampling of nine' private wells west and northwest of the L-P plant indicate that past releases
from L-P do not currently pose a significant health risk for users of existing wells. EPA does
not believe that future well users will be 'at risk from the low levels of formaldehyde leaching
from the western sump.
The selected remedy for the L-P site under the Superfund program is not a
determination regarding actions that may be warranted under other regulations and statutes.
For example, in April 1995 the California Regional Water Quality Control Board (RWQCB),
acting under its own authority, ordered L':'P to conduct additional groundwater monitoring to
evaluate the presence of formaldehyde in the area west of the plant.
The selected remedy does not require that the existing well permit restrictions be
retained. However, the Butte County Department of Public Health has indicated that it
intends' to retain its existing well permit restrictions until L-P has completed the study
required by the RWQCB's April 1995 Order. At that time, any further action regarding well
permit restrictions would be at the discretion of the County and the RWQCB.
The selected remedy requires no further. action for surface soils, since the arsenic
levels in site soils are within background concentrations for this area. The requirement in the
Interim ROD for deed restrictions. prohibiting future residential use of the property, which'
was based on concerns about arsenic levels in surface soils, is rescinded. Residential
development of the L-P plant site is currently prohibited by the Butte County zoning
ordinance which allows only industrial use of the site and by the existing deed restrictions,
which were established to comply with the 1990 Interim ROD. However, since arsenic levels
in surface soils at the plant do not exceed background levels, the selected remedy does' not
require that the deed restrictions be' continued.
5.0 SUMMARY OF SITE CHARACTERISTICS
. EPA began investigating contamination of soils, ,groundwater, surface water, sediments
and air at the L-P site in 1987. Areas on the site where PCP was historically used and where
PCP could have been released into the environment by L-P were investigated. In these
locations, PCP was either not detected or detected in only trace levels at shallow depths.
Based. on these results and a similar study of the Koppers site, EP A concluded that the
contaminant plume in the regional aquIfer that extends south of the Koppers and L-P sites,
originated solely from the Koppers property (see Figure 5-1).
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EPA's investigations at the L-P plant
and landfill found that groundwater, surface
water, soil, sediment and wood waste
contain various contaminants used by L-P
and Koppers. Concentrations at the L-P
plant were found to be highest in an area
along the KopperslL-P boundary (see Figure
1-2). Contaminants in this area came
primarily from the Koppers site and will be
addressed as part of the Koppers cleanup.
Elsewhere at the L-P plant and landfill~
arsenic and formaldehyde were present in
concentrations high enough to be of
potential concern.
In 1990, EPA completed its
Remedial Investigation (RI) and Feasibility
Study (FS) for the L-P site and issued an
Interim Record of Decision (ROD). The
1990 Interim ROD identified arsenic and
formaldehyde as the only two contaminants
of concern for soil and groundwater. The
potential future exposure routes of concern
were 1) ingestion of soil associated with
residential use of the plant property and 2)
use of groundwater beneath the plant or
landfill as a source of domestic water
supply.
5.1 Soils
The limited soil data collected during
the Remedial Investigation suggested. that
arsenic levels in log deck soils might be
above naturally-occurring levels for this
area. However, additional sampling
(summarized in Table 5-1) has shown that surface soil at the L-P plant contains arsenic at
concentrations comparable to background levels for this area of Oroville.
Figure 5-1. Koppers Plume Area
5.2 Groundwater
The L-P plant is underlain by two aquifers and an intervening aquitard (see Figure 5-
2). The shallow aquifer typically extends from the ground surface to a depth of 20 to 40 feet,
existing primarily in the dredge tailings deposited by gold mining operations during the early
1900s. The aquitard is a fine-grained silt and clay layer that restricts (but does not stop)
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GROUNDWATER (May 1992 - January 1'995)
(all values in ppb, or ~g/L)
Shallow aquifer at the Plant
--------ARSENIC ---------
Maximum Average
45.9 9.1
-- FORMALDEHYDE --
Maximum Average*
.200 38
Regional aquifer at the Plant
1.8
0.8
55
21 .
Regional aquifer at the Landfill
3.3
1.6
52
21
SOIL (May 1992)
(all values in ppm, or mg/kg)
Surface soil at the Plant
---~----~------------ ARSENIC --------------------
Maximum. Average Background'
4.6 2.7 S 6.5 .
NOTE:
ppb = parts per billion concentration.
ppm = parts per million concentration
~g/L = micrograms per liter .
mg/kg = milligrams per kilogram
* the detection limit for .formaldehyde is 20 ppb. Thus, an average concentration of 21 ppb
means that formaldehyde was detected in only one or two samples ever the last three years.
Table 5-1. Summary of Contaminant Concentrations in Groundwater and Soil.
downward movement of water from the shallow aquifer into the regional aquifer. There is no
shallow aquifer beneath the L-P landfill, which is located on a bluff to the east of the plant.
The top of the deeper, regional aquifer ranges from 40 to 70 feet below ground surface.at the
L-P plant, and the aquifer extends to depths of over 200 feet.
5.2.1 Arsenic in Groundwater
Data collected from both shallow and regional aquifer monitoring wells over the last
three years are summarized in Table 5-1. Arsenic levels in the regional aquifer beneath both
the plant and the landfill were consistently low, with an average concentration of 0.8 parts per
billion (ppb) at the plant and 1.6 ppb beneath the landfill. These levels are within the range
of background concentrations for the regional aquifer, based on data from both the L-P and
Koppers sites.
Arsenic is present in the shallow groundwater at the plant at an average concentration
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and regional aquifer
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of 9.1 ppb and ranges from a minimum of less than 1 ppb to a maximum of nearly 46 ppb.
The highest shallow aquifer arsenic levels were consistently found in well ML-5, which is
located about 60 feet south of the log deck pond (see Figure 1-2). Arsenic levels here ranged
from roughly 8 to 46 ppb. It is not clear from the existing data whether the higher arsenic
concentrations in well ML-5 are naturally occurring or related to a contaminant source such
as sediments in the log deck pond.
. In March 1995, EPA sampled nine private wells located west and northwest of the L-P
plant along Pacific Heights Road. Arsenic levels were below the detection limit of 2.5 ppb in
seven wells. Concentrations in the remaining two wells were approximately 5 and 24 ppb.
5.2.2 Formaldehvde in Groundwater
Formaldehyde is one of the primary chemicals in the "glue" used by L-P in the
manufacture of hardboard at the Oroville plant. In surface waters, formaldehyde biodegrades
(breaks down) relatively quickly; however, its fate in subsurface soil and groundwater has not
been well studied. .
. Up until late 1988, L-P discharged the washwater from its "glue kitchen" into the
western sump, which is a small unlined pond on the western side of the plant (see Figure 1- -
2). The washwater often was contaminated with formaldehyde, and as water seeped through
the sides and bottom of the unlined sump, formaldehyde contamination spread to the
surrounding shallow groundwater. In October 1988, L-P modified operations in the glue
kitchen and began recycling the washwater wit~ the plant. -
Over the last three years, formaldehyde has been detected in shallow groundwater
beneath the plant and less frequently in regional groundwater beneath the plant and the
landfill (see Table 5-1). In the shallow aquifer, formaldehyde was found consistently only in
samples collected from the monitoring wells near the western sump. In this ~ea, the average
concentration was 65. ppb, with a maximum of 200 ppb. In regional groundwater beneath the
landfill, formaldehyde was detected once in only one weil (at 52 ppb).
In March 1995, EPA sampled nine private wells located west and northwest of the L-P
plant along Pacific Heights Road. Formaldehyde was detected in only one of those wells, at -
a concentration of 86 ppb.. .
6.0 SUMMARY OF SITE RISKS
In September 1989, EPA completed an Endangerment Assessment (EA), which
examined the current and potential future risks-to public, health from contamination at the L-P
site. The EA used results from the Remedial Investigation (RI) to determine the contaminants
of concern. The EA then determined the possible exposure pathways (that is, ways people
could be exposed to contaminants now and in the future) and calculated the risks associated
with those exposures.
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The 1990 Interim ROD identifi'ed three exposure pathways that might be subject to
cleanup actions under the Superfund program: 1) use of the shallow aquifer beneath the plant
for water supply, 2) use of the regional aquifer beneath the landfill for water supply, and 3)
contact with surface soil by future residents at the plant property. .
6.1 Risks from Exposure to Shallow Groundwater
Groundwater in the shallow aquifer beneath the L-P plant contains arsenic and
formaldehyde at low concentrations. There are no existing water supply wells in the vicinity
of the L-P plant that pump solely from the shallow aquifer, whereas several wells provide
drinking water from the deeper regional aquifer. Some of the private wells located west and
northwest of the L-P plant may be screened at depths that could permit drawing water from
both the shallow and regional aquifers, although the lateral extent of the shallow aquifer in
those areas has not been determined.
6.1.1 Formaldehyde
There is no federal drinking water standard for formaldehyde, although at the time the
1990 ROD was written, the California Dept. of Health Services had an advisory Drinking
Water Action Level of 30 ppb. The inhalation of formaldehyde vapors can cause cancer;
however, the ingestion of water containing formaldehyde is not believed to cause cancer.
The 1989 EA calculated a cancer risk from exposure to formaldehyde in groundwater based
on the assumption that formaldehyde vapors might be released during typical domestic use
(primarily showering) and inhaled. Following generally conservative (that is, health-
protective) assumptions used by EPA at the time, the EA determined that a formaldehyde
concentration of 5 ppb would present a one in one rr.illion excess cancer risk.
In May 1995, EPAissued a supplement to the EA that contains a revised assessment
of the health risks associated with exposure to formaldehyde in water using new .
toxicityiexposure information and techniques that have become available since preparation of
the original EA. The supplement concluded that the cancer risk via showering associated
with the maximum formaldehyde concentration measured in the last three years (i.e., 200 ppb)
is below one in one million. The supplement goes on to recommend t~at drinking water
criteria for formaldehyde be based on non-cancer health effects, and it concludes that 1,000
ppb is a safe maximum allowable level of formaldehyde in drinking water. The State of
California's Department of Health Services recently raised its action level for formaldehyde to
1,000 ppb.
Both the maximum and the average concentrati~ns of formaldehyde detected in the
shallow aquifer at the plant over the last three years are substantially below the recommended
limit for non-cancer health effects. Similarly, the maximum formaldehyde concentration
found by EPA during the remedial investigation (650 ppb in 1988) is well below this limit.
6.1.2 Arsenic
Under the Safe Drinking Water Act, EPA's federal drinking water standard for arsenic
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is 50 parts per billion (ppb). Based on the results of sampling conducted over the last three
years, the average arsenic concentration in the shallow aquifer does not exceed federal
standards. The average concentration of arsenic in the shallow aquifer (9.1 ppb) represents' an
excess cancer risk level of approximately 3 in 100,000.
6.2 Risks from Exposure to Regional Groundwater
In the five wells sampled at the landfill over the last three years, formaldehyde was
detected once in only one well (at a concentration of 52 ppb in August 1992). This
concentration is well below the. recommended limit of 1,000 ppb for drillking water.
6.3 Risks. from Exposure to Surface Soil
. As noted earlier, the arsenic levels in surface soils at the plant are within the range of
local background concentrations. Therefore, there is no elevated risk from exposure to these
mili. .
7.0 DESCRIPTION OF THE NO-ACTION ALTERNATIVE
The 1990 Feasibility Study (FS) for the L-P site evaluated a full range of remedial
alternatives for soil and shallow groundwater based on the assumption that contaminant levels
were high enough to require cleanup. However, the additional data collected since the 1990
Interim ROD have shown that 1) there are no elevated contaminant levels in either the surface
soil at the plant or the regional aquifer beneath the plant and landfill, arid 2) contaminants in
the shallow aquifer beneath the plant are present at low levels.
During the process of developing the proposed plan, EP A continued to evaluate only a
limited number of alternatives (ranging from no action to institutional controls) for soil and
groundwater. The sel~cted alternative would require no further action to restrict exposure to'
groundwater in the shallow aquifer or soil at the L-P plant. No further groundwater
monitoring is required, and the requirement in the Interim ROD for institutional controls (well
permit restrictions and deed restrictions) is withdrawn. .
, .
. .
8.0 EXPLANATION OF SIGNIFICANT CHANGES
The proposed plan for the L-P site was released for public comment in May .1995.
EPA's preferred alternatives wa.s documented in the plan. At that time, EPA proposed no
further remedial action for ~ither soil or groundwater as the final remedy at the site, including
the withdrawal of institutional controls established pursuant to the 1990 Interim ROD. EP A
has reviewed all written and verbal cOl1}IIlents received during the public comment period. In
the limited comments received from the public, one party supported the proposed remedy,
while two others expressed concerns about the validity of the data but did riot explicitly
propose that EP A select an alternative remedy. The selected remedy is the same as the
preferred alternatives for soil and groundwater presented in the proposed plan.
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III. RESPONSE SUMMARY
Louisiana-Pacific Superfund Site
. Oroville, California
u.s. Environmental Protection Agency
Region 9
San Francisco, California
July 1995
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RESPONSE TO PUBLIC COMMENTS on the PROPOSED PLAN
, ' for the
Louisiana-Pacific Superfund Site
Oroville, California '
1. INTRODUCTION
, '
, ,
, ' ,
The United States Environmental Protection Agency (ltEPAIt) held a public comment
period from May 20 through June 19, 1995 on'EPNs Proposed Plan for the final remedy at
the Louisiana-Pacific (ltL-PIt) Superfund Site in Oroville, California. The pUrpose of the '
comment period was' to provide interested, parties with an opportunity to comment on the
Propos~d Plan and related documents prepared since the 1990 ,Interim Record of Decision for
the L-P' site. The Proposed Plan and other documents comprising the AdininistIative Record
were made available on May 20, 1995 at the Butte County Public Library iil Oroville and at
the Meriam Library, California State University at Chico. By May 19, 1995, fact sheets,
containing EPA's Proposed Pian had been mailed to all interested parties. ' Notification 'of the
public comment period was published in the Oroville Mercury-Register newspaper. '
EPA held a public meeting on June 1, 1995 at the Oakdale Heights School in Oroville,
California. At this meeting, EPA repre~entatives described the,alternatives evaluated, .,
presented EP A's preferred alternative and answered questions about the evaluation of the L-P
site and, the remedial alternatives under consideration. "
Section 113(k)(2)(B)(iv) of the Comprehensive Environmental Response, Compensa-
tion and Liability Act (ltCERCLAIt) requires that EP A respond to significant comments on
EP A's Proposed Plan.. This Response Summary provides a review and summary of significant
comments on the Proposed Plan. In addition to summarizing significant concerns and
questions, the Response Summary presents EPA's responses to those concerns.
II. OVERVIEW OF THE RECORD OF DE~ISION
, '
During the process of developing' the final:r~medy proposed plan for soil and
groundwater contamination, EP A evaluated a limited number of alternatives. 'EP A's preferred
alternatives are described'below. ' ' ','
Groundwater Alternative - No Further Action '
EPA's selected a,ltno further actionlt remedy for groundwater. The additional data
collected since the 1990 Interim ROD have shown that 1) there are no elevated contaminants
in the regional aquifer beneath the plant.and landfill,.'and 2) contaminants in the shallow'
aquifer beneath the plant are present at low levels that do not pose a, significant risk to either
human health or the environment. No further groundwater moriitoring is required~ and the
requirement in the Interim ROD for institutional controls (well permit restrictions) is withdrawn.
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Soil Alternative - No Further Action
EP A also selected a "no further action" remedy for soil. The additional data collected
since the 1990 Interim ROD have shown that there are no elevated contaminant levels in the
surface soil at the plant. The requirement in the Interim ROD lor institutional controls (deed
restrictions) is withdrawn.
III. SUMMARY OF COMMENTS AND AGENCY RESPONSES
EP A received both written and verbal comments during the public comment period of
May 20 - June 19, 1995. These comments and the EPA responses are presented in this
section of the Response Summary.
The originators of comments are identified in parentheses by last name, company or
agency abbreviations. Written comments were received from the following:
. Louisiana-Pacific Corporation (L-~).
. Verbal comments on the Proposed Plan were received from two individuals and
transcribed during the public meeting held June 1, 1995 in Oroville, California. The
comments, which are documented in the meeting transcript (available in the Administrative
Record), were received from the following individuals:
. James Hansen
. Otto Hansen.
1.
The lab tests have been falsified. (0. Hansen)
Response: There is no evidence to support this claim. In order to ensure the
quality of laboratory data, laboratory tests are conducted according to strict.
quality assurance (QA) and quality control (QC) procedures that are reviewed
and approved by EP A before sampling work begins. After samples are collected
and submitted to the lab, the analytical results are put through a data validation
process to ensure that the laboratories are complying with QA/QC requirements.
These quality. control procedures are' described in detail in the Quality Assurance
Project Plan, which is part of the Remedial Design Work Plan prepared by
Louisiana-Pacific. Both documents are part of the Administrative Record for this
site. ' ,
2.
What, laboratories analyzed the samples? Were any samples sent to Eureka Labs? (J.
Hansen)' '
Response: No samples were sent to Eureka Labs. Over the last three years, L-P
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has used the CH2M Hill's Quality Analytical Lab in Redding, CA (also known as
Quality Analytical Laboratories) for the analysis of both soil and groundwater
samples from the site. During the earlier remedial investigation (RI) of the site
conducted by EP A, a number of labs were used for sample analysis. However,
no samples were sent to Eureka Labs.
EP A is aware of the data quality problems associated with samples analyzed by
Eureka Laboratories. Although none of the samples from the L-P site were sent
to this lab, two of the labs that analyzed RI samples for EP A were later found to
have produced questionable data. The samples that were sent to these labs (for
analysis of organic contaminant levels in soil) represented only a portion of the
soil samples collected and analyzed. EP A has gone back to review the data
obtained from these labs and the extent to which it was used in decision-making
for the site. The agency concluded that the questionable lab samples were not
critical to decisions made at the site and that the remaining data met the data
quality standards.
3.
L-P has no objection to the proposed "no further action" remedy. (L-P).
Response: Comment acknowledged.
4.
In the 1989 draft Endangerment Assessment (EA), EP A's subcontractor used a
sophisticated exposure modeling approach. to evaluate the risk associated with
showering. Based on this modeling, the subcontractor estimated the excess cancer risk
for the maximum plausible exposure case to be 1 x 10.6 (or one in one million). The
draft EA has been "revalidated" by the supplement and supports the agency's proposal to
require no further action. (L-P) -
Response: With respect to risks posed by formaldehyde inhalation associated
with showering, the results of the subcontractor's proposed modeling approach
are consistent with the conclusionS of the 1995 supplement, i.e., this pathway of
exposure does not pose a significant risk to human health at the levels of
formaldehyde contamination found at the L-P site.
At the time the Endangerment Assessment (EA) was being prepared, EPA
Region 9's policy was to assume that the in-home inhalation exposure to an
organic chemical that volatilizes from domestic water (i.e., the inhaled daily
dose) is equivalent to the amount that would be ingested by drinking two liters of
that water. As a result, the modeling approach proposed by the contractor in the
draft EA for the L-P site was not used in the 1989 final EA.
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EP A's 1995 supplement to the EA employed a screening level analysis based on
a simplified equilibrium model to evaluate risks associated with formaldehyde
inhalation during showering. Overall, this type of analysis will tend to overstate
exposures/risks. Since this analysis concluded that the inhalation pathway is not
a pathway of concern for formaldehyde released during showering, EP A did not
pursue the use of a more. sophisticated model to estimate inhalation risks.
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