RECORD OF DECISION REMEDIAL ALTERNATIVE SELECTION SITE Triangle Chemical Company. Inc., Texas State Highway 87, Bridge City Texas DOCUMENTS REVIEWED I have reviewed the following documents describing the analysis of cost- effectiveness of remedial alternatives for the Triangle Chemical Company site - Triangle Chemiceil Company Site Investigation, Roy F. Weston, Inc., September, 1984 - Triangle Chemical Company Feasibility Study, Roy F. Weston, Inc., Marcln/ 1985. "* "" ; " - Staff summaries and recommendations DESCRIPTION OF SELECTED REMEDY 0 Storage tank and drum contents - offsite incineration, deep well Injection 0 Storage tank sludges - offsite landfill. 0 Onsite structures - decontaminate and leave onslte. 0 Trash - offsite landfill. 0 Contaminated soil - onsite mechanical aeration DECLARATION Consistent with the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) and the National Contingency Plan (40 CFR Part 300), I have determined that the selected remedy for the Triangle Chemical Company site 1s a cost-effective remedy and provides adequate protection of public health, welfare and the environment. The State of Texas has been consulted and agrees with the approved remedy In addition, the action will require future operation and maintenance activities to ensure the continued effectiveness of the remedy. These activities will be considered part of the approved action and eligible for Trust Fund monies for a period of 1 year. 173802
Transcript
RECORD OF DECISIONREMEDIAL ALTERNATIVE SELECTION
SITE Triangle Chemical Company. Inc., Texas State Highway 87, Bridge CityTexas
DOCUMENTS REVIEWED
I have reviewed the following documents describing the analysis of cost-effectiveness of remedial alternatives for the Triangle Chemical Company site
- Triangle Chemiceil Company Site Investigation, Roy F. Weston, Inc.,September, 1984
- Triangle Chemical Company Feasibility Study, Roy F. Weston, Inc., Marcln/1985.
"* "" ; "
- Staff summaries and recommendations
DESCRIPTION OF SELECTED REMEDY
0 Storage tank and drum contents - offsite incineration, deep well Injection0 Storage tank sludges - offsite landfill.0 Onsite structures - decontaminate and leave onslte.0 Trash - offsite landfill.0 Contaminated soil - onsite mechanical aeration
DECLARATION
Consistent with the Comprehensive Environmental Response, Compensation, andLiability Act of 1980 (CERCLA) and the National Contingency Plan (40 CFRPart 300), I have determined that the selected remedy for the TriangleChemical Company site 1s a cost-effective remedy and provides adequateprotection of public health, welfare and the environment. The State ofTexas has been consulted and agrees with the approved remedy In addition,the action will require future operation and maintenance activities toensure the continued effectiveness of the remedy. These activities will beconsidered part of the approved action and eligible for Trust Fund moniesfor a period of 1 year.
173802
I have also determined that the action being taken is appropriate whenbalanced against the ava i l ab i l i ty of Trust fund monies for use at othersites In addition, offsite destruction of l iquids and secure dispositionof solids is more cost-effective than other remedial action and is necessaryto protect public health, welfare or the environment.
// 7?<Kta«_^H^MB^JlW_L«^M / X—X' ™" ' y ~ f ^*^ W-^p'*
DATE Dick Whittington,Regional Adminl:
Region VI
TRIANGLE CHEMICAL COMPANY RECORD OF DECISION CONCURRENCES
Ailyn M *Davis, 1)1rectorAir and Waste Management Division
Samuel I. Nott,"Superfund BranchAir and Waste Management Division
a a r a r e e n e , iefSolid Wasteland Emergency Response BranchOffice of Regional Council
HilHam Rhea, ChiefHazardous Materials BranchAir and Waste Management Division
Divita, ChiefAir BranchAir and Waste Management Division
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
TRIANGLE CHEMICAL COMPANY
BRIDGE CITY, TEXAS
TABLE OF CONTENTS
Site Location and Description 1
Site History 1
Current Site Status 3
Migration Pathways 5
EL Enforcement Analysis 6
Alternatives Evalueitlon 7
Community Relations 16
Consisting with Other Environmental Laws 17
Recommended Alternative 18
RECORD OF DECISIONREMEDIAL ALTERNATIVE SELECTION
TRIANGLE CHEMICAL COMPANYBRIDGE CITY, TEXAS
Site Location and Description
The Triangle Chemical Company site 1s a 2.3 acre tract located on TexasState Highway 87, approximately one-half mile north of its junction withState Highway 62 just north of the Bridge City, Texas city limits asshown in Figure 1. The site Is bound on the north by a commercial property,on the south by a residence, on the east by Highway 87, and on the westJ>yCoon Bayou, In an area that is projected to become Increasingly urbanized1n the next decade (Figure 2). The population of Bridge City 1s approximately10,000 people. There are 15 houses and 50 mobile homes within 1/4 mile ofthe Triangle Chemical site.
Natural grade elevations at the site range from four to seven feet abovemean sea level. The site Is located In the 100-year floodplain as identifiedby the Federal Emergency Management Agency. However, the combination offrequently intense rainfall, gentle site slope, and poor drainage and tidalInfluences 1n the bayou system, which discharges Into the Sablne Riverapproximately three miles downstream, has resulted in inundation of thesite once every 6 years.
Groundwater Is a major part of the public and industrial water supply Inthe region and Is furnished by the Chicot and Evangel1ne aquifers, whichare hydrologically connected and considered a single unit called the GulfCoast aquifer The shallow water table normally lies about 6 feet belowthe ground surface However, during periods of heavy rain the water tablehas risen to as high as 2 feet below the surface.
The site surface Includes five -buildings and thirty tanks, as seen 1n Figures3 and 4. Twelve of the tanks currently contain hazardous liquids totalling51,000 gallons The buildings were used for office space, processingareas, and loading areas.
Site History
The Triangle Chemical Company operated a chemical mixing and blendingfacility from the early 1970's to 1981. During the company's operatingperiod various types of industrial cleaning compounds, automobile brakefluid, windshield washer solvents, hand cleaners, and pesticides wereproduced Raw materials and finished products were stored in bulk surfacestorage tanks and 55-gallon drums on the site
STATE HIGHWAY
FIGURE 1SITE VICINITY MAP
TRIANGLE
CHEMICAL
COMPANY
\ *
LEGEND
tzzi
] UrbanAgricultureForestWetlandsRangeland
Water
SOURCE AREAWIOE WASTE TREATMENTMANAGEMENT PLANSOUTHEAST TEXAS AREA 1976
FIGUPE 2PROJECTED
PEGIOflAL LAND USE1995
N
SCALE10
i I 1 i1 2 3 4
1/2" • MILES
i5
i
APPROXIMATEPROPERTYLINE
LOADING DOCK
BROUSSARDPROPERTY
;: TANKS
PROCESS BALDING
OO00
So
OFFICE /LAB
OOOO
OO
1°TANKS
-K-
STATE HIGHWAY B7
FIGURE 3TRIANGLE CHEMICAL COMPANY
SITE
REOBIRDCHEMICAL
INSIDE PROCESS BUILDING
COON BAYOU INLET
PROCESS BUILDING
LOADING DOCK / S6
BROUSSAROPROPERTY OFFIC
LAB
•RED BIRDCHEMICAL
STATE HISHWA^ 87
LEGEND
EMPTY TANK
TANK CONTAINING LIQUIDS
Fiqure 4
LOCATION OF PROCESS
AND STORAGE TANKS
TRIANGLE C H E M I C A L C O M P A N Y
During the latter period of plant operation, numerous fish kills in CoonBayou were reported by the local residents Documented fish kills near thesite are listed in Table 1. Subsequent Investigations by the TexasDepartment of Water Resources (TDWR) indicated that these fish kills couldhave been the result of discharges of hazardous materials from the site.In August 1981, TDWR acquired a temporary injunction against TriangleChemical Company, calling for compliance with pollution control laws andprevention of further untreated discharges from the site
In October 1981, TDrfR found the site to be abandoned. Limited sampling ofdrums, spill areas, runoff areas, and Coon Bayou documented that hazardousmaterials were located onsite and were migrating offsite via stormwaterrunoff and direct discharge reinforcing the possibility that the fishkills could have been caused by hazardous material spills from the site.The drums stored onsite were noted to be in a deteriorated condition withsome bulging and leaking. ^ _
After the Trustee 1n bankruptcy for the Triangle Chemical Company Indicatedthat the company assets were Insufficient to perform any necessary cleanupwork at the site, the Environmental Protection Agency (EPA) Initiated anImmediate Removal Action under the Comprehensive Environmental Response,Compensation, and Liability Act (CERCLA) to deter public access to hazardousmaterials on the site In April 1982. This action consisted of (1) buildinga six-foot high chain link and barbed wire fence around the material storagearea, (2) posting warning signs around the site, and (3) constructing adrainage canal 1n front of the main drum storage area to prevent runofffrom reaching Highway 87. The cost of this action was $8,082 25
In August 1982, a Planned Removal Action was conducted to remove the drumsand contaminated debris at the site Under this action, the drums werestaged and liquids were pumped to bulk transport trucks for offsite disposal.Empty drums were crushed and removed from the site along with contaminatedtrash and soil The soil removal operations were limited to the drumstaging and crushing area. The wastes removed from the site during thisaction were taken to an approved hazardous waste disposal site owned byChemical Waste Management, Inc. 1n Port Arthur, Texas and Included 21,000gallons of liquid, 350 cubic yards of contaminated soil and trash, and1,095 55-gallon drums The cost of this action was $74,755.25.
In July 1982, TDWR nominated the Triangle Chemical Company for inclusion onthe National Priorities List. The site ranked high enough to be placed onthe list and became eligible for remedial Investigation/feasibility study(RI/FS) funding In August 1983, a cooperative agreement between EPA andthe State of Texas was approved, awarding $183,000 to conduct the studies.Roy F. Weston, Inc. of Houston, Texas was selected to conduct the RI/FS.The onsite activities for the remedial Investigation were completed 1nApril 1984 and the final report was received 1n September 1984 TheFeasibility Study was initiated in August 1984 and completed 1n March 1985.
TABLE 1
DOCUMENTED FISH KILLS ON COON BAYOU
DATE
03/27/76
09/06/77
10/24/77
03/25/78
05/05/78
11/2/81
10/19/82
LOCATION
Near SH 62 & Winfree Rd.
Near Confluence of CowBayou
Private Pond Adjacent toCoon Bayou & Hoo Hoo Rd.
Between US 87 and Mouthof Coon Bayou
Between US 87 and Mouthof Coon Bayou
Near Hoo Hoo Rd Bridge
Private Pond 1 Mile
CAUSE NO.
Low D 0.
Low D.O
Low D 0.
Low D.O.
Low D.O.
Low D.O
Low D 0
FISH KILLED
No Count
10,000
1.250
-*..'
^1,000-V
38
No Count
No CountUpstream From Plant
In response to suspected unauthorized activities on the Triangle property,a third emergency action was undertaken to completely enclose the site witha six-foot chain link fence in March 1985
Current Site Status
The site investigation performed at the Triangle Chemical Company generatedsubstantial Information concerning the regional geology, site geology andhydrogeology, and site geochemistry.
Regional stratigraphic information is presented 1n Table 2. Bridge Cityand Orange County are located in the southernmost surface exposure of theBeaumont Clay Formation, consisting primarily of interdistributary muds anddistributary sand-j and silts of the Pleistocene Age. As seen 1n Figure 5,the soils at the site consist primarily of sllty clays of the formation.The uppermost stratum 1s a dark brown, clayey silt containing some organ-losfiber, representing a weathered soil horizon of the Beaumont formation. _,._-Underlying the cl<*yey silt Is a sllty clay containing trace fine sands. "*"This soil layer was found to be stiff and moist during the site Investigation.
Within the silty clay unit are lenses of light brown silt containing tracesof clay and very fine sand. This silt 1s typically saturated and soft,varying 1n thickness from 2 feet to 5 feet across the site.
Adjacent to Coon Bayou, a light gray silty clay was identified underlain bya black silty clay containing a significant amount of organic fiber.
Groundwater elevations, monitored during the site investigation, indicatethat shallow groundwater occurs across the site at depths of 2 to 6 feetbelow the surface. Fluctuations in the shallow water table elevation areassociated with local weather conditions During periods of heavy rainfall,the water table has been identified as high as 2 feet below the surface.Based on measured groundwater elevations, horizontal groundwater flowoccurs in a northeasterly direction across the site and discharges intoCoon Bayou The Influence of tidal variations on the water table elevation1s not significant enough to effect overall groundwater flow.
As seen in Table 3, the onsite shallow groundwater 1s slightly contaminated.Because the maximum contaminant concentrations are well below theconcentrations established by the National Drinking Water Standards and theClean Water Act water quality criteria (Table 4 and 5, respectively), thegroundwater does not present a significant threat to human health and theenvironment. It should be noted that the shallow groundwater 1s presentlysubject to future contamination from leaching of contaminants due to anelevated water table during severe rainfall events.
The site is located immediately adjacent to Coon Bayou, which is a tributaryof the Cow Bayou and Sablne River drainage systems. There are no streamgauging stations In Coon Bayou, however, flow variability in Coon Bayou 1ssimilar to the variability of Cow Bayou, in which the flow ranges from 0 to4,600 cubic feet per second (cfs), with an average of 101 cfs Both bodiesof water are Influenced by tidal fluctuations, extremely high tides have,1n some cases, temporarily reversed the flow in both bayous
•TABLE 2STRATIGRAPHY OF THE
TEXAS GULF COAST REGION
" V"t •«
•• £
n
t
1
r̂,,.
II. 1 >c nr
CI lit M-I-W
r,,n,,n.
MIoctM
\\OlU<M»M(t)
V\X\,
•v\
EocrM
rclrowM
Srr«il*r*f>hlc ttalti
All "1 ~Krinra nt 1 ItfIhnlfarrj r nuttimIhMlli) > nut InnWllll S.nd
Col 1*4 s.nj
Pltvlnt FniMtlm
Onkvlllo S«nJ«ton»
!¥•»* p*rt ofC.t.lo In Tuff
CntchenU Tuff or Sanditoneor lM4«imM>
AiuhiMc ronvtle*
Trio" F« rut Ion
£«rf«* S iti urf«c*rrlo Cl r "'ll hur« <"'<>•»
* hlng CI'J f*rfrr
?. lllh»- S til tunr rtrahTr nriilllt* .inl'.t mr M..JN r
*; Whit. .It nil r l»^h tA Fnrvntlonj N M r II If sanut w* HrwbrrS .nqil t« < Inr lfc.«b.-r
•5 lillurtli S.ml»l nt Hrnfcrr£ ltlnHlK| ( lay
W-lllNrn «ivl»linr1 nlh II 1 mil 1 n
) i; i« F ir». t Inn^ i n k floint.ln r nutlonu n ... i b BM i
1 ? U. hrt r !•'! 1 inr° WH^ lit. .nlu Hrkl.v rniwtl n
i rrl* anilWilt > GroupHI h"r Cri up
«)>rfro(>olof l< Unit*
Oil cot M^ilfrr
f*>n(.lln* ••.nlfrr
•nrk.vlllr "*" >.confining
c-^X•y>l«i >v(r».trlct»4) >v
Hnl 4lirn«.«4•• lyilroloRlc milt*
tn Ihlf ffBnrc
<*ltcl*4 fnniul fwrk.r.
1
j
IntfJti fr(NW <|>
1
III "t« « «M.bIII Nn 4 ff IV Iw
III J • -N ft»l ^>
,,,.U r̂.,
1, ..Uwr*.̂
JH»fnni»i>i niKt'n i>
Ir »«l»U*"»ll njKH<Afit« Mni«i yWrff f i
f r < r«t«M (nn,Wkwi*
\ HMMrftf hfrtpJrt»im>III wfv >i yiiji n*l'l|Sft»lr t (««•<<•
t i rff ilwlnnMilf̂ IMM
, J
^ . .
\
f
5 . f
(••.tk.
QMtvrnnry SjritM umllffrr |»li(t*l*4 MI ttvrll n.
Collail S«n4 nvrrl«nfr4 rn 1 tt«¥«r« Countr i
1
iO«k«lllr <i.nd»tni«. In luit>-il Inrln>ln« fonMtlon . > t i 1Mohlnflon Covntjr |
1
Catahovla Tnfl 4«.lflMilff1 M.C«t«lMHil« Santltinnv »• I < fL*v«c« Comly
MMlnMC «>4 "frln" fpnul 1 n ,••7 to Pllftncenr In «(|r
Frlo Cl*7 owrl.pf^d nr if I
Live (M*. Cnnnty ^ i
In4lc*t»4 •»•»»»« "f Mill rtt ifnmMtlnn npplT In **ttli jcnvtrnl T»Mn« Wtlt.fttFnnMtlon r*«t nl l«rn».CoMitf MT to In r"t nr InUwl*. Oll«. c««w In «ic
FIGUPF 5SITE GEOLOGY
ORGANIC CLAYEY SILT (ML)
SANDtSP)
BLACK ONSANKSILTY CLAY (CL)
CLAYEY SILT TOSH.TV CLAY (ML-CL)
SCALE mmZCNTM. I 4tfVCftTKAL f 4
LEOEND
TGROUND lUMFACE
OEfTN OF WELL CAtlNQ OB COIIINO
JL LENGTH OF WELL SCREEN A SANO PACK
-*- WATER TABLE
OEOLOQIC CONTACT
-?- OEOLOQIC CONTACT (INFEMMED)
•UatUMFACE CMOB8
•ECTION
1AILF 31RIAMRLF CWMICAL COMPAfK
ANALYTICAL PFSULTSGROUMDWATERS
OM«OWD WIT OP MM Mr- ID M»-l Mf-0 M»-l PIOO LAB OrTICTIOMCONCENTRATION WELL 1 WELL 1 DUPLICATE WHJ. t WOJL t DUPLKXTE WELL > BLANC BLANC LIMIT
Phenol*
P"Chraalu*
Copper
Lead
Hletel
Sliver
Zlne
IOC
Specific Conductance
MIA3
Oil ft Creese- Infra Rad
Oil ft Greaie-Oravlaatrlv
Priority rbl latent Volatile**
ftfethylena Chloride"
Priori!* Pol latent Baa* RMtralf
Dl-n-nmyl PMhalato
Bla tt-ethyl Be*yl) ptithalele
PHorlty Pot latent Pmtlelde*
Delta BHC
Priority Pollatant Aeld BitMelablet
Pentai hlorophenol
•V/l HP - HP
T 1 T 1
•V/l HP - "P
•V/l HP HP
•V/l HP - "P
•V/l HP - HP
•V/l HP - HP
•V/l OS - II
•V/l TS 1 SI 1 Ml
• riMM/OB t 100 - STT
•V/l " " "P
•V/l — - HP
•v/i - w
•v/1 n M
of/I SI — HP
of/i *• — nr
•V/l — -- tr«e«
""
HP HP HP OOS
I J I S --
— j HP HP IS
— II HP -- 11
HP HP - SI1
-- t 11 HP -- II
— , HP HP — II
II HP — li1
— 1 MS II — IIri
— \, 4 tn i is
— HP — I I*
. . . . HP I S
. . . . - 1 I
'II
-- ' tS St It IIr
f
l— HP HP — II
-- 1 HP HP — I I
t
t
' 1
1
- H P ~ II
• M*-l alia had no* priority pollvlanl retail la prefe*)! Review of lean Indicate* (utxlanca to be t-octeMI epproxlianely SI of/I
* Volatile organic compounds detected at Triangle Chemical Company '
Data generated during the site investigation, presented in Table 6, showsthat the surface water directly adjacent to the site is only slightlycontaminated Concentrations of contaminants detected are well belowdrinking water and Clean Water Act water quality standards. Therefore,contamination of surface waters from the site is not considered to besignificant
During the site Investigation, several 55-gallon drums of chemical productwere observed in a building on property owned by the Triangle ChemicalCompany, north ol Redbird Chemical Company These drums are in deterioratedcondition, and pose a threat to human health due to direct contact with thepublic. Therefore, disposal of these drums is addressed as part of theremedial action eit the site.
The results of the site investigation and supplemental sampling performed,during the feasibility study indicate that approximately 51,000 gallons ofhazardous materials are stored 1n 12 above ground storage tanks onsite.The analytical results of samples taken from these tanks are presented inTables 7 and 8.
The results of the site Investigation also indicate that soil contaminationis restricted to past drum and tank storage areas onsite. Concentrationsof metals detected are within the range of levels found to occur naturallyin the soil in the area Onsite soil contamination is extensive forvolatile organics compounds (VOC), as seen in Figure 6, which illustratesthe lateral and vertical extent of soil contamination of greater than 500parts per million total volatile organics. Concentrations of specificvolatile compounds found in the soil are listed in Table 9. A total of 1,900cubic yards of contaminated soils are onsite, no contaminated soils weredetected offsite
The following conclusions were developed from the remedial investigation
0 Near surface soils on the site have been contaminated frommigration of the waste materials through spills and leaksfrom drums and tanks
0 Groundwaters below the site are not significantly impactedby the facility
0 Surface waters in the vicinity of the site are not significantlyimpacted.
0 Air quality at the site has not been measurably Impacted.
0 A large quantity of general refuse, a portion of which ispotentially contaminated with chemical product, remainsonsite
0 A drum storage area on Triangle Chemical Company's northernproperty remains unsecured
TABLt 6TPIANRLE CHEMICAL COflPANY
ANALYTICAL PESULTSSURFACE WATERS
GOVPOUNU
PhenolsPHChromiumCopperLeadNickelSl iverZinc
PMOM ty Pol lutant Base Neutrals
Di-n-Butyl PhthalateDie thyl Phthalate
UNIT OFCONCENTRATION
•*/!mg/1mg/1mg/1n\j/ 1mg/1mg/1mg/1
ug/lug/1
B-!VINLET
NF6 2
NF0 19
NFNFNF
0 04
22NF
B-1W-D HELDINLET DUPLICATE BLANK
_. .7 2 » 7 0- , NF
- 11-- '. NF— f NF-- ,- NF— i NF
ic
i38 13
NF 13
!
j.
44 '
1
r
A-t
DETBCTSONLIMIT
005-050351102
1010
Hr
, I
TABLE 7
ANALYTICAL RESULTS OF TANK SAMPLINGDUPING EMFRPENCY RESPONSE ACTION
AUGUST, 1982
COMPOUND*
Trichloroethylene
1,1 ,2-Tnchloroethane
Benzene
1,1 ,2,2-Tetrachloroethene
Toluene
Napthalene —
Ethyl Benzene
2-Ethylhexyl Phthalate
1,2-Dichloroe thane
2-Chloroethylvinyl Ether
1 ,4-Dichlorobenzene
1 ,2-Dichlorobenzene
N-Nitrosodiphenylamine
PCB (polychlorinated biphenyls)
Chromium
Copper
Lead
Nickel
Silver
Zinc
Mercury
TANK NUMBERA2 A3 A4 B3 B4
2,351 — — — 16,000
13 — — — 401
10 52 — — 72
39 — — — 550
620 733 412 — 3,400
1.112 - 4 — — 6,285~*
— 132 77 — 20,000
— — — — 220,000
— — — — 7JO— — — 2,000
— — — — 5,561
— — — — 43,500
— 218 800 — —
— 75 — — —0 15 — — 0.02 150
11 0.35 4.0 0.07 5.8
2.5 — 1.0 0 09 7.1
0.5 0 2 0.03 1.3 0 3
0.2 — — — —
12 9 05 1.1 04 —
~ — — — o 003
21**
69
—
—
—711
-58
82
309•
—
—
*.
—
—0.04
0.42
0.3
0 06
—0 09
—
* All concentrations o1 organic compounds expressed as parts ner billion (pob)All concentrations o1 inoroanic compounds (metals) exoressed as parts per billion(ppb)
** Tank No 21 was reldbeled as S6 in this investigation
HUL.C. '
TR1/NGLE CHEMKAL COMPANYANALYTICAL RESULTS ON TANK CONTENTS
•a CaacaatratiMa naattaJ ara ta ka aaarf aa aa«l-«aaatlflcatlaa aal
The following target receptors were identified in the remedial investigation0 Materials released onto the ground surface from the storage
tanks would either percolate into the soil or flow into CoonBayou The risk to receptors via surface water migration hasbeen documented by fish kills caused by past releases ofsimilar materials that were stored 1n 55-gallon drums whichwere disposed of during a removal action in August 1982
* A sudden release of materials in the tanks would also presenta risk to persons living and working in the area and drivingpast the site clue to volatile orgamcs released to theatmosphere and direct contact with contaminated soil.
e The volatile organic compounds detected in the soils, severalof which are suspected mutagens, teratogens, and carcinogens, -«* -could be released to the atmosphere during future development - - -of the site affecting worker health and safety. Toxldtycharacteristics and routes of exposure for the volatile organiccompounds found in the soil and tanks are listed in Table 10.
No significant migration of airborne contaminants onsite was detectedduring the remedial investigation.
Migration Pathways
Groundwater
The Triangle Chemical Company site is underlain by the Beaumont Formation,one of five formations that make up the Chicot Aquifer of the Texas GulfCoast
The Chicot Aquifer is the youngest aquifer in the coastal plain of Texasand includes the Willis Sand, Bentley Formation, Montgomery Formation,Beaumont Clay and Recent Alluvium Recharge to the lower portions of theChicot Aquifer occur at outcrops of the Willis, Bentley and MontgomeryFormations, north of Orange County. The Willis Sand consists principallyof reddish sands and gravel, silt and clay. The Willis Sand is not knownto yield freshwater to wells in Orange County and contains slightly tomoderately saline water. The Bentley and Montgomery Formations consist ofa basal gravelly sand grading upward into finer sand, silt and clay. Muchof the sediments of these formations are similar to the Willis Sand fromwhich they were at least partly derived.
The deltaic coastwise plain of the Beaumont Clay forms the land surface ofall of Orange County except along rivers and the coast where it is coveredby Recent Alluvium. Much of the surface exposure of the Beaumont Clay inthe northern part oF the County is covered by fine sandy loam because of agreater proportion of sand near the base of the formation. Southward theBeaumont becomes progressively more clayey. While the Beaumont is generallydescribed as consisting of clay it contains much sandy material which canbe locally utilized for water supply Sand beds in the Beaumont Clay yieldfreshwater to domestic and livestock wells in Orange County
ifTOXICITY DATA FOR ELECTED ORGANICS FOUND H SOILS AND TANKS
AT IRIANGLE CHIMICAL COMPANf
wucwt aCMCIMOGM
MwciTMancs4
••
•nfiB (F luuftaaj•OH
pansJtoetam X X K X X
Carbon Dlaulf Ida X X X X X X
Chlorobcntene X X X X X
DlehlorobentflM X X X X
1,2-DlcfiloroethrlMw X X X
Mmam X X X X X X
EtliyL MAJMAO X X X X X
X X X X X X
an X X X X X
X X X X X X X
Olchlorabaman* X X X j X X
DLchlxvoatham X X , X X
Ethyl bantam X X X j X X
Napttalam X X X ' X X
1,1,2,2-tttnchloro- X X X X t X Xethana ,
Ttiluena X X X X [ X X
1,1,2-Ttlchlocwthana X X X > K X
Trichloroathylflna X X X X X X
The recent alluvium in bayous supplies small quantities of groundwater totemporary residences. Although the alluvium is capable of furnishing largequantities of groundwater, large scale development would induce or acceleratemovement of saline water from the rivers Into the aquifer, eliminating thepotential for using the aquifer as a major resource
As previously discussed, shallow groundwater 1s encountered between 2 and6 feet below the surface of the site. Fluctuations in the shallow watertable occur primarily due to local weather conditions, rising duringperiods of heavy rainfall and falling during drier periods Although atidal influence is seen in the water table, fluctuations due to thisinfluence are not significant.
The remedial Investigation confirmed minor contamination of the shallowgroundwater. The fluctuations in the water table and heavy rainfalls _^ „associated with 1hese fluctuations indicate that the observed groundwater"contamination 1s due to periodic leaching of soils when the water table hasrisen. Based on the observed contamination, soil permeability (10~3 cm/sec),and direction of flow, It Is possible that soil contaminants leached Into thegroundwater could impact Coon Bayou.
Surface Water
Surface water has been contaminated from the site from runoff during floodevents and from leaking tanks and drums. Seventy-five percent of the sitelies in the 100-year floodplain as designated by the Federal EmergencyManagement Agency, and portions of the site have been inundated at leastonce every six years Potential exists for future contamination of surfacewater due to erosion and transport of contaminated soil and a release ofcontents from deteriorating onsite storage tanks
Air
Results of the remedial investigation Indicate that air quality in the areahas not been adversely affected by the site. Volatile organic compoundswere released from the soil surface after spills from tanks and drums onthe site, but no contaminants were detected 1n the soil within one foot ofthe surface. Volatile organics were detected In soils 1 to 5 feet deep Inconcentrations as high as 500 ppm, and could be released suddenly duringfuture site development It is unlikely, however, that significant airquality degradaton will occur 1f the site surface remains undisturbed.
Enforcement
Potentially responsible parties (PRPs) for Triangle consist of the TriangleEstate which is currently in Chapter 7 Bankruptcy, approximately sixcompanies and corporations that have either owned Traingle Chemical or weresister companies of Triangle operating from the same location, and officersof the companies cind corporations associated with Triangle. None of thecompanies involved are solvent.
The State of Texas obtained an injunction against Triangle In August of1981 This injunction required Triangle to comply with all pertinent rulesand regulations At the time of this injunction, Triangle was operatingunder Chapter 11 Bankruptcy rules Approximately two months after theinjunction, the Texas Department of Water Resources (TDWR) discovered thatthe facility had been abandoned
In August 1982, EPA Region VI forwarded a cost recovery case developmentplan to Headquarters This CERCLA cost recovery action was for moniesexpended in the emergency and planned removal actions begun 1n April 1982,and continuing through August 1982. This cost recovery action is pendingin the bankruptcy court
Due to the insolvency of the entities Involved with Triangle, remedialaction could not be obtained in a timely fashion through litigation.However, PRPs will be offered the opportunity to voluntarily Implement -J« -the selected remedy.
Alternatives Evaluation
The feasibility study for the Triangle Chemical site was performed todetermine what actions, 1f any, would be appropriate as part of a permanentremedy for the site. Several alternative remedial methods were developedto cost-effectively mitigate damage to, and provide adequate protection ofpublic health, welfare and the environment from past and future releases ofcontaminants in storage tanks and soil currently onsite
The National Contingency Plan, 40 CFR Part 300 68 (e) (2) states that"Source control remedial actions may be appropriate If a substantialconcentration of hazardous substances remains at or near the area wherethey were originally located and inadequate barriers exist to retardmigration of substances into the environment." In accordance with theplan, and based on the conclusions of the remedial Investigation, a sourcecontrol remedial action 1s necessary at the Triangle Chemical site.
The major threats to public health and the environment attributed tocontaminants at the site are
1 Direct contamination of groundwater
2. Rupture of storage tanks, releasing contaminants to the soil,surface water,, and atmosphere.
3. Uncontrolled releases of volatile organic contaminants 1n thesubsurface soils resulting from future developmental excavation
Remedial Objectives
The feasibility study performed by Roy F. Weston Associates in March 1985developed the following objectives based on the results of the remedialinvestigation0 Remove and dispose of the contents of the storage tanks in an
approved disposal facility, and decontaminate the tanks
8
0 Prevent significant degradation of the shallow groundwater.
0 Prevent significant degradation of surface water.
0 Reduce contamination in the soil to mitigate future Impacts onhuman health, the environment, and site development
0 Remove and dispose of the trash 1n and around the buildingsonsite
At the time the facility was abandoned, 1,095 55-gallon drums used forstoring raw materials and products were located on the site. Therefore,closure of the site must be 1n compliance with the Resource Conservationand Recovery Act (RCRA) 40 CFR 264.178, which states that "at closure, allhazardous wastes and hazardous waste residues must be removed from thecontainment system. Remaining containers, liners, bases and soil containingor contaminated with hazardous wastes or hazardous waste residues must bedecontaminated o? removed " The Permit Applicant's Guidance Manual forHazardous Waste Land Treatment, Storage, and Disposal Facilities statesthat, at closure of a facility, soils are considered to be decontaminatedwhen the concentrations of hazardous constituents are at background levelsfor soil 1n the area.
Criteria to measure the accomplishment of the objectives developed for thecontaminated soil were established based on time-weighted average permissibleexposure limits (TWA-PEL) and short term exposure limits (STEL) for volatileorganic compounds identified in the soils and regulatory requirements forthe closure of container storage facilities These TWA-PEL's and STEL'sare listed 1n Table 11 Appropriate levels of soil clean up based on these,criteria were determined to be 100 ppm of total volatile organics, the mostconservative STEL, and 25 ppm, the most conservative TWA-PEL Based on theregulatory requirement for facility closure, the appropriate level ofclean up would be background.
Clean up criteria were not established for the removal of the tank contentsClosure of the tanks will be done in strict accordance with 40 CFR 264.197,with appropriate decontaminatldn of the tank Interiors
In accordance with Section 300.68 of the National Contingency Plan, severalremedial methods were developed in the feasibility study to accomplish theobjectives established for the permanent remedy at the site. Two methodswere developed to dispose of the contents of the storage tanks, two methodsto address the on'»1te structures, seven methods to address the onsitecontaminated soil, and one method to address trash and debris on the site.A no-action alternative was also evaluated.
Initial Screening of Alternatives
Section 300 68 (hi states that the following broad criteria should be usedin the initial screening of alternatives (methods)
TABLE 11PERMISSIBLE EXPOSURE LIMITS
FOP VOLATILE COMPOUNDSFOUND AT TPIANRLE CHEMICAL COMPANY
2 JOCIH IMA > |Mrio9n Confaranc* at OovacTtJantal and XaduBtrUl a^aniata (NXIH) tia*
3 ICSLK 8m - MOB 4fhort tan 9B&9UT9 li*lt.
(1) Cost For each alternative, the cost of installing or implementingthe remedial action must be considered, Including operation and maintenancecosts. An alternative that far exceeds (e g by an order of magnitude) thecosts of other alternatives evaluated and that does not provide substantiallygreater public health or environmental benefit should usually be excludedfrom further consideration.
(2) Effects of the alternative. The effects of each alternative shouldbe evaluated in two ways ID whether the alternative itself or ItsImplementation has any adverse environmental effects, and (11) for sourcecontrol remedial actions, whether the alternative is likely to achieveadequate control of source material, or for offsite remedial actions,whether the alternative 1s likely to effectively mitigate and minimize thethreat of harm to public health, welfare, or the environment. If analternative has significant adverse effects, it should be excluded from,further consideration. Only those alternatives that effectively contrlboteto protection of public health, welfare, or the environment should beconsidered further.
(3) Acceptable Engineering Practices. Alternatives must be feasible forthe location and conditions of the release, applicable to the problem, andrepresent a reliable means of addressing the problem.
Each of the remedial methods was evaluated based on these criteria. Therationale for preference of remedial methods 1s outlined below.
Methods for Disposal of Tank Contents
1. Offsite incineration/deep well injection/solidification and offsitelandfill
This method involves incineration of 32,100 gallons of ignitable liquids,deep well injection of 24,000 gallons of non-igmtable organic liquids, andsolidification and offiste landfill disposal of 375 cubic yards of organicsludges The method provides for destruction of more than half of thehazardous materials In the tanks, and minimizes the potential for directcontact with the sludges and materials that cannot be Incinerated.There are several commercial incineration and Injection facilities 1n thearea, thereby reducing the risks associated with transporting hazardousmaterials For these reasons, the method 1s retained.
2. Solidification and Offsite Landfilling of all Tank Contents
This method involves the use of inorganic sol Ids to absorb the liquidsand transform the waste into a dry sold material, which is transported toan offsite landfill for disposal. The method is significantly more costlythan the incineration/deep well injection method without providing acommensurate increase in protection, and is therefore rejected
10
Method for Disposal of Drums and Contents
1. Offsite Incineration and deep well injection of contents/offsitelandfill of empty drums
This Is the only method developed for the disposal of 135 drums that arecurrently stored on the northern portion of Triangle Chemical Company'sproperty The contents can be bulked with similar liquids from thestorage tanks and disposed of very cost-effectively.
Methods for Disposal of Contaminated Soils
1. Excavation of contaminated soil and disposal in an offsite landfill
This method is retained In the initial screening. This method involvesremoval of the contaminated soils, and the disposal of these soils in an -approved landfill offsite. The site would then be backfilled and gradedwith clean soil. Human contact with the contaminated material and thepotential for future groundwater contamination would be eliminated, therebymeeting all of the objectives for remedial action.
2. Excavation of contaminated soil and disposal in an onsite RCRA landfill
In this method, a RCRA approved hazardous materials landfill for disposalof contaminated soils would be constructed onsite This method is rejectedfor the following reasons (1) location of a landfill 1n the 100-yearfloodplain is not a recommended practice, (2) because the wastes wouldremain onsite, a continued threat of release of wastes will exist, (3)construction of a landfill will require demolition of the onsite structures-,(4) extensive long-term maintenance and monitoring will be required, and(5) the costs are significantly higher than offsite transport and disposalwith no additional health or environmental benefits
3. In-Situ mechanical aeration of soils
Aeration of the soils 1s a physical decontamination method whereby thecontaminated soils are exposed to the atmosphere and the volatile organiccompounds are released under controlled conditions. Contamination Is reducedto background levels in a short period of time, and capacity to managewastes from other contaminated sites 1s created by not utilizing space atan offsite landfill. Post-closure activities associated with this methodInclude groundwater monitoring and site maintenance. Also, this method Isthe least costly of all of the methods developed for soil remediation andwill meet all of the objectives developed for the site. For these reasons,the method 1s retained for further evaluation.
114 In-Situ Forced Air Injection Aeration of Soils
This method may be technically Infeasible for use with the type of soilfound at the Tricingle Chemical site. The clay soils will hinder the movementof air, thereby requiring extensive amount of time and electrical energyfor adequate exposure of the subsurface soils and release of the volatilecompounds to the atmosphere. Associated with these time and energyrequirements are higher operating costs, making this method more costly thanmechanical aeration while not providing a commensurate Increase 1n protection.For these reasons, the method Is eliminated from further consideration.
5. Encapsulation of Contaminated Soil
Construction of a protective cap over the site would provide adequateprotection of the public from direct contact with the contaminated soil,as long as the cap is properly maintained and no future site development -takes place. However, enscapsulation would not accomplish the objectivesof preventing groundwater contamination and mitigating future Impacts dueto surface development, and would be difficult to maintain due to thelocation of the site.
By allowing contamination to remain In the soil, a significant potentialfor groundwater contamination will exist, and long-term groundwater monitoringwill be required In order to detect an contaminant migration from the siteIf contamination Is detected, future remedial action addressing thegroundwater may be required
Capping the site will not eliminate the potential for uncontrolled releasesof volatile organic compounds during future site development activities,thereby posing a <,enous health threat to future construction workers atthe site
Because the site is located in the 100-year floodplaln of Coon Bayou,deterioration of the cap will be significant and long-term maintenancecosts will be extremely high A cap is Infeasible along the bayou shoreline,where tidal action will cause continual cap erosion and exposure ofcontaminated soil.
For the reasons discussed above, encapsulation is rejected as a remedialmethod
Disposal of Trash and Debris
1. Segregation and Disposal in an Offsite Landfill
Trash and debris will be separated into contaminated and uncontaminatedmaterial The contaminated material will be disposed of in a RCRA-approvedhazardous materials landfill. Over 95% of the material is non-hazardous,and will be buried in a sanitary landfill. All of the material will beremoved from the site, eliminating the potential for direct contact
12
Methods for Addressing Contaminated Buildings and Structures
1 Decontamination
Buildings will be steam cleaned and remain onsite The rinsate will becollected and disposed of by deep well injection. The method 1s technicallyeffective and will eliminate the risk of public exposure to contaminants.Also, it may be possible to salvage the prefabricated buildings afterdecontamination. The method is retained.
2. Demolition and Removal
Demolition and removal of the onsite structures 1s rejected becausecapital costs are significantly higher than the cost of decontamination,without a commensurate Increase 1n benefits.
-.* -The comparative costs of each of these methods are listed 1n Table 12.The costs associaled with excavation to 25 ppm and 100 ppm are listed forcomparison of methods that would not attain full compliance of Federalregulations, but would provide adequate protection of public health basedon established health criteria. For all soil alternatives that are notdesigned to reduce contamination to background levels, a total presentworth of $75,800 must be added for site management and long-term monitoring.For example, the total present worth of site encapsulation (infiltrationcontrols) with mechanical aeration including capital costs and operationand maintenance is $227,800
Description of Remedial Action Plans**
The alternative methods that were retained after the initial screening arecombined into alternative remedial action plans for a permanent remedy atthe site Cost estimates and brief descriptions of the technical feasibility,implementability, and environmental effectiveness of each plan are listed1n Table 13 Detailed descriptions of the methods included in each planare given below
The methods Involving the disposal of onsite debris and storage tank contentsand the decontamination of onsite structures are common to all of thealternative plans, and therefore need not be evaluated with each plan Forcomparative purposes, the estimated costs of these methods are included inthe total remedial plan estimates.
Disposal of Tank Contents and Decontamination of Tanks
Approximately 32,000 gallons of liquids and sludges 1n the onsite storagetanks are amenable to incineration based on laboratory analysis of flashpoint,organic content, and heat value One commercial incinerator operates nearthe Triangle Chemical site, thereby reducing risk and cost associated withtransporting hazardous materials
TABLE 12
SUMMARY OF REMEDIAL ACTION METHOD COST ESTIMATES
REMEDIAL METHODTOTAL CAPITAL
COST
MONITORING AND MAINTENANCE
ANNUAL PRESENT WORTH*TOTAL PRESENT
WORTH
Tank Contents
Solidify and Landfill All ContentsDeep Well Inject and IncinerateLiquids, Solidify and LandfillSludges
Contaminated Soils
Excavaton to Background Qualityand Onsite Disposal
Excavation to 25 ppm VolatileOrganics and Offsite Disposal
Excavation to 100 ppm VolatileOrganics and Offsite Disposal
Excavation to Background Qualityand Off site Disposal
Mechanical Aeration for VolatileOrganics Removal
Forced Air Injection for VolatileOrganics Removal
Infiltration Controls with Excavationand Offsite Disposal
Infiltration Controls with MechanicalAeration
Trash and Debris
Segregation and Offsite Disposal
Buildings and Structures
$151,000118,000
$151,000118,000
1,510,000
781,000
572,000
868,000
62,000
173,000
164,000
152,000
14,000
1,510,000
781,000
572,000
868,000
62,000
173,000
164,000
152,000
14,000
Demolition and RemovalDecontaminate and Remain Onsite
614,00094,000
614,00094,000
TABLE 12 (CONT )
SUMMARY OF REMEDIAL ACTION METHOD COST ESTIMATES
REMEDIAL METHODTOTAL CAPITAL
COST
MOMITQDIMQ MAINTENANCE
ANNUAL PRESENT WORTH*TOTAL PRESENT
WORTH
Drums and Contents
Removal with Offsite Disposal
Site Management
39,100**
* Present worth values based on a discount rate of 10% over 30 years.
** Cost will vary according to most applicable disposal technology.
39,100
Infiltration ControlAll Other Methods
Method 2626
,000,000
5,300500
494
,800,800
7530
,800,800
TABLE 13SUMMARY OF ALTERNATIVE REMEDIAL ACTION PLANS
FOR TRIANGLE CHEMICAL COMPANY
PLAN
. Disposal ofTank Contentsand Trash,Decontaminationof Structures,Excavation toBackgroundQual i ty
>. Disposal ofTank Contentsand Trash,Decontaminationof Structures,MechanicalAeration ofSoils toBackgroundQual i ty
TECHNICALFEASIBILITY
i
Utilizes con-ventional tech-nologies.Limits of con-tamination tobackgroundqual i tyunproven.
Utilizes con-ventionaltechnologies,except soilaerationmethod. Pilotstudy recommend-ed prior to fullimplementation.Limits of con-tamination tobackgroundquality unproven
ENVIRONMENTALEFFECTIVENESS
Removes allwastes and con-taminated mater-ials from site.A1r emissionsduring excava-tion and tankopening.
Utilizes con-ventional tech-nologies. Fielddeterminationof soil con-taminant zonelikely to beimprecise.
Some contaminat-ed soils leftonsite. Con-tamination belowshort-termexposure limits.Air emissionsduring excavation.
Requires 2months.Performduring dryseason
871,000 , 500 5,000 876,500
TABLE 13 (CONT.)
PLANTECHNICALFEASIBILITY
ENVIRONMENTALEFFECTIVENESS
IMPLEMEN-TAB1LITY
CAPITALCOSTS
MONITORING/MAINTENANCE COSTSANNUAL PKtbENT WORTH
TOTAL PRESENTWORTH
4. Disposal ofTank Contentsand Trash,Decontaminationof Structures,Mechanica1Aeration ofSoils to 100ppm VolatileOrganics
5. Disposal ofTank Contentsand Trash,Decontaminationof Structures,Excavation ofSoils to 25ppm VolatileOrganics
6. No Action
Utilizes con-ventional tech-nologies, exceptsoil aerationmethod. Pilotstudy recommend-ed prior to fullimplementation.Field determin-ation of soilcontaminant zonelikely to beimpreci se
Same as 3
N/A
Some contaminatedsoils left onsiteContaminationbelow exposurelimits. Airemissions duringexcavation.
Same as 3except con-tamination isbelow timeweightedaverageexposurelimit.
Does not accom-pli sh siteobjectives,Inconsistentwith land useprojected forarea. Poten-tial for humanexposure andthreat tohealth andsafety, poten-tial for con-tinued con-taminantmigration
Requires 2-3monthsPerformduring dryseason
377,000 500 5,000 382,000
Same as 3 1,080,000 500 5,000 1,085,500
NA NA NA NA NA
13
Deep well injection is an appropriate disposal alternative for 24,000gallons of non-igmtable liquids currently onsite. There are severalfacilities in the Gulf Coast Region which Inject non-flammable, low sol Idswaste into saline groundwaters 4,000 feet below the ground surface. Thistechnology, although not destructive, will essentially eliminate potentialhuman contact with the tank materials.
The sludges in the tanks would be solidified with an Inorganic solid andlandfilled at a permitted offsite landfill facility. Tanks would then bedecontaminated by recirculatlng detergent water and rinsing. Final rinsatesamples would be analyzed to certify that a tank would be decontaminated.Larger tanks would also be mechanically scoured, if necessary. All of therinsate would be disposed of by deep well Injection.
Trash and Debris Removal with Offsite Disposal^ -
Offsite disposal Is the only remedial action which 1s applicable to thesite. Ninety-five percent of the trash Is considered non-hazardous, andwould be transported to a sanitary landfill 1n the area That portion ofthe debris that 1s obviously stained would be considered hazardous, andwill be disposed of In a RCRA approved hazardous materials landfill.
Decontamination ol Onsite Structures
Decontamination would be accomplished by steam cleaning all floors, ceilings,walls, and internal structures The rinsate would be collected and disposedof by deep well injection. Certification would be required to ensure thatthe buildings were decontaminated before any future use would be possible.
4,
Offsite Disposal of Drums and Drum Contents
The materials which are currently stored on the Triangle Chemical Companyproperty north of Redbird Chemical, will be analyzed and bulked with similarmaterials found in the onsite storage tanks. The materials will then beincinerated or deep well injected, as appropriate The drums will bedecontaminated, crushed, and disposed of in a RCRA approved landfill.
Differences in the alternative remedial action plans are attributed to theremedial methods developed as a permanent remedy for soil contamination atthe site. Only the descriptions for the soils portion of each plan aregiven below. The complete plans Include the selected remedial methods forthe tank contents, drum and debris removal, and decontamination of theonsite structures
14
Plan 1 - No Action
In accordance with Section 300.68 (g) of the National Contingency Plan(NCP), a no action alternative should be evaluated. This plan involvesleaving the site conditions as they currently exist. Section 300.68 (h)(2) states that an alternative having significant adverse environmentaleffects or that does not effectively mitigate and minimize the threat ofharm to public health welfare and the environment should be excluded fromfurther consideration The no action alternative would allow the site tocontinually pose a threat of (1) a release of volatile organic contaminantsin the soil to the atmosphere during future site development or flooding,(2) leaching of volatile organics Into the groundwater during periods ofheavy rainfall due to an elevated water table, (3) a release of tank contentscausing extensive soil and surface water contamination, and (4) exposure ofthe public during unauthorized entry to the site. The risks to public Ui _health and the environment associated with the no action plan are unacceptableand the no action plan Is rejected.
*
Plan 2 - Excavation and Offsite Landfill
Contaminated soils are limited to the areas onsite where releases from drumsand tanks had occurred during and inrnediately after operation of the facility.The soils to be removed lie In a narrow band extending from about 1 footbelow ground surface to just above the perched ground water table found atabout six feet A front end loader and a backhoe are required to excavatethe soils and load trucks for offsite transport. A four-foot dike wouldbe built to provide protection from the 100-year flood during the excavationperiod Soils from the dike would be used as backfill after the contaminatedsoil 1s removed from the site Excavated soils would be transported anddisposed of in a RCRA approved double-lined landfill. Various levels ofclean up were used for cost estimates based on (1) permissible exposurelimits for several of the compounds Identified 1n the soil and (2) regulatoryrequirements for facility closures Volatilization of contaminants Isexpected to occur during excavation and transport. Thus soil being placedIn a landfill may riot be contaminated at the time of disposal. Becausevolatilization will be much more difficult to control during excavationthan during aeration, excavation may result In an undesirable environmentaleffect at the site.
The pros and cons of this alternative are listed below
Pros
+ Equipment required is readily available 1n the area.+ Utilizes conventional technology.+ Removes contaminants from the site+ Only two months required for implementation+ Eliminates potential of future groundwater contamination+ Eliminates potential for release of volatiles during
future site development
15
Cons
- Volatilization of contaminants will occur during excavationand transport,
- Very high cost due to requirement for double-lined landfillfacility
- Double-lined facility may not be readily available.
Plan 3 - In-S1tu Mechanical Aeration
Contaminated soils will be exposed to the atmosphere under controlledconditions using A tractor with a disc harrow Treatment consists of four-pass tilling of a six-inch soil layer. Treated layers will be excavatedand stored 1n a diked area for use later as backfill. Soil sampling willbe used to verify decontamination prior to excavation. Reduction of j^,contaminant concentrations to background levels will take approximately 2'hours depending upon the ambient air temperature at the time of remedialaction. Flood control structures will be built around the till- area tocontrol run-on, and provisions will be made to manage possible runoff fromthe 1-hour 25-year rainfall event. The material from the dike, nativeclays, will be used as final cover and grade material for the site. Agroundwater monitoring program will be established to ensure that thegroundwater will be adequately protected by the remedy The existingmonitoring wells will be supplementaed with one new shallow well at thenorth property boundary, downgradient of contaminated soil Area B.Air monitoring will be used to control the aeration operation The area!extent of tilling <an be varied to ensure that no offsite air qualitydegradation occurs
Pros
+ Least costly alternative to Implement.+ Volatilization can be monitored and remedy can be
Implemented under strictly controlled conditions.+ Does not depend upon the availability of an approved
double-lined facility.+ Capacity at an offsite facility not consumed+ Potential for volatilization during future site
development would be eliminated.+ Risk due to transport of hazardous materials 1s
eliminated+ Action can be completed within one month
Cons
- Innovative technology, would require a pilot study.- Background levels not set- Remedy would have to be implemented during dry season
16
In the initial screening, the construction of an onsite RCRA approvedlandfill for the disposal of contaminated soils and trash was rejected.The cost of this construction was estimated to be $1,510,000 The expenseInvolves the special construction requirements for floodplain protectionand demolition of all onsite sturctures to provide enough area to build alandfill. Excavation of the soil to background levels and disposal at anapproved offsite facility is estimated to cost $684,000. The costs ofIncineration and deep well injection of the tank contents must be added toeach of these, and the cost of debris disposal and structure decontaminationmust be added to the offsite disposal alternative. The total cost of theonsite landfill alternative plan would be $1 63 million versus $1.17 millionfor the offsite disposal alternative.
Excavation of the soil to background levels and offsite disposal, Incombination with the recommended actions for the structures, tank and drumcontents, and onsite debris also complies with the applicable environmentallaws and regulations However, this 1s much more costly than the recommendedalternative ($1.17 million versus $393,000) and does not offer a commensurateIncrease in benefits to human health and the environment. Also, becausevolatilization of the organic contaminants will occur during excavation andtransport, it Is likely that the soils will be effectively decontaminatedprior to landfill disposal, and that landfill capacity could be better usedfor hazardous materials from other sites Therefore, excavation and offsitedisposal is not as cost-effective as mechanical aeration.
Excavation of soil to 100 ppm and 25 ppm would provide adequate protectionof human health and the environment based on permissible exposure limits tocontaminants found in the soil, but would not fully comply with applicablelaws and regulations The difference 1n cost between excavation to 100 ppm*and excavation to background concentration is $296,000 ($1 17 million versus$876,000), and between excavation to 25 ppm and background levels is $86,500.However, groundwater monitoring would be required for a 30 year post-closureperiod, and future corrective actions may be required if contaminantmigration via groundwater was detected. It would therefore appear thatexcavation to background would be more cost-effective than excavation toeither 100 ppm or 25 ppm, when the potential for future groundwater actionsat the site is considered
Community Relations
Very little public Interest has been expressed. The public notice periodbegan on April 5, 1935 and ended on April 19, at which time the publiccomment period began, A public meeting was held 1n Orange, Texas on May 1.Five people attended the public meeting, and no statements were made. Thepublic comment period ended on May 10, 1985, one comment was receivedduring the peroid The comment and a written response are included in the"Responsiveness Summary" section of this Record of Decision
17
Consistency with Other Environmental Laws
It is EPA policy to give primary consideration to remedial actions thatattain or exceed applicable and relevant standards of other Federal publichealth and environmental laws The environmental laws which will have animpact on the proposed remedies for the Triangle Chemical site Include
1 The Resource Conservation and Recovery Act substantiverequirements,, 40 CFR Part 264, for closure of tanks andcontainer storage facilities.
2. Executive Order 11988, Floodplain Management for siteslocated in flood plains.
3. Clean Water Act, water quality crietria for human healthand drinking water. - "**•**.
4 Occupational Health and Safety Administration time weightedaverage-permissible exposure limits for air quality monitoring
Closure of tanks and containers Is regulated by the Resource Conservationand Recovery Act (RCRA) subparts I and J. Subpart I is the applicableregulation governing the closure of facilities in which hazardous materialswere stored in containers The subpart indicates that containers and soilcontaining or contaminated by hazardous wastes must be decontaminated orremoved The regulations in subpart J apply to facilities that use tanksto store hazardous wastes and state that, at closure, all hazardous wastesand residues must be removed from the tanks RCRA also requires thatoffsite landfills used for disposal of hazardous wastes be double-lined, *RCRA approved facilities These requirements would also govern theconstruction of an onsite landfill. A brief description of all theapplicable and relevant RCRA regulation is given 1n Table 14.
Executive Order 11988 applies to the protection of floodplains. The TriangleChemical site is located 1n the 100-year floodplain. Therefore any onsiteremedy should be designed with consideration given to floodplain protection.
The Clean Water Act outlines water quality criteria for human health Thesenumerical standards are applied to address the issue of "how clean 1s clean"for the shallow groundwater at the site.
The Occupational Safety and Health Administration time weighted average-permissible exposure limit standards are applied to ensure that no degradationof offsite air quality will occur during remedial action.
TABLE 14RCRA REGULATIONS APPLICABLE TO TRIANGLE CHEMICAL COMPANY
40 CFRREGULATION
DESCRIPTION OFREGULATION
APPLICABILITY TOTRIANGLE CHEMICAL
IMPACT ON CONTAMINANTSREMAINING ONSITE
264 18
264 50
264.90
264 178
Facilities located <«100-year flood plainmust be designed,constructed, operatedand maintained toprevent washout of anyhazardous waste by a100-year flood.
A contingency plan tominimize hazards duringan unplanned releasemust be developed byowners of a hazardouswaste facility.
Facilities that treat,store, or dispose ofhazardous waste mustestablish groundwaterprotection standardswhich may Include long-term monitoring for30 years.
Soils containing hazardouswastes and waste residuesmust be removed ordecontaminated.
Parts of the site areinundated by 5 feet ofwater in a 100-yearflood. Tidal surges maycause additional structuraldamage
Liquids to be storedonsite are hazardousand Ignitable.
Liquids to be storedonsite are hazardous.Hazardous wastes mayremain in the soil.
Hazardous wastes havebeen found in onsitesoils.
No present flood protectionTanks may need reinforcement,and contaminated areas mayneed to be diked
A contingency plan would berequired.
Legal Interpretations mayrequire groundwater monitoringIf hazardous wastes are leftonsite.
Allowing wastes to remain onsitemay be a violation of RCRA.
TABLE 14 (CONT.)
40 CFRREGULATION
DESCRIPTION OFREGULATION
APPLICABILITY TOTRIANGLE CHEMICAL
IMPACT ON CONTAMINANTSREMAINING ONSITE
264 191
264 192
264 192
Owners which feat orstore hazardous wastesin tanks must conformto tank design standardswhich define structuralintegrity.
Tanks used to storecorrosive hazardousliquids must be equippedwith an Inner liner orother corrosioninhibition system
Storage of hazardousliquids in tanks re-quires an Inspectionschedule to assesstank conditions whichIncludes at leastweekly spot checksfor signs of leakage.
Liquids to oe storedonsite are hazardous,
Some liquids to bestored onsite arecorrosive.
Liquids to be storedonsite are hazardous
Existing tanks are of unknownstructural integrity and mayneed to be modified
Tanks have no known linersor corrosion Inhibitionsystems and must bemodified.
Weekly tank Inspectionssignificantly Increase sitemanagement costs.
TABLE 14 (CONT.)
40 CFRREGULATION
DESCRIPTION OFREGULATION
APPLICABILITY TOTRIANGLE CHEMICAL
IMPACT ON CONTAMINANTSREMAINING ONSITE
264 197
265.198
Ign1table liquids mustbe separated and managedwith respect to extremeheat or pressure,uncontrolled toxic mists,and uncontrolled flammablefumes.
Ignltable liquids mustbe stored In tankswhich comply withrequirements of theNational F1re ProtectionAssociation.
Some liquids to bestorea onsite areignitable.
Some liquids to bestored on-site areIgnltable.
Cornellance withregulations may requirecostly monitoring instrumentation.
Compliance may requirecostly construction oftank storage area dikesand proper drainagesystems.
Agency considerscontamination to beremoved when theconcentrations ofhazardous constituentsin the soil are atbackground levels
Sets criteria forsoil cleanup
Required for fullcompliance with FederalEnvironmental Regulationsand Guidance.
18
Recommended Alternative
Section 300 68 (j) of the National Contingency Plan states that "Theappropriate extent of remedy shall be determined by the lead agency'sselection of the remedial alternatives which the agency determines Is cost-effective (i e the lowest cost alternative that Is technologically feasibleand reliable and which effectively mitigates and minimizes damage to andprovides adequate protection of public health, welfare or the environment)."
To this end, incineration and deep well Injection of the tank and drumcontents, decontamination of all onsite structures, offsite disposal oftrash and debris, and mechanical aeration of the contaminated soils Is therecommended remedial action for the Triangle Chemical site. Schematicdrawings of the mechanical aeration method of this alternative are presented1n Figures 7 and 8. This alternative complies with the closure requirementsfor tanks (40 CFR 264 subpart J) and container storage facilities (40 CFR264 subpart I). This alternative 1s also the lowest cost alternative that -"""will comply with all applicable and relevant Federal environmental laws andregulations Decontamination of the soil to background levels would effectivelymitigate the potential for future groundwater contamination.
Operation and Maintenance
Post closure monitoring and maintenance will be required for any remedialplan selected for the Triangle Chemical site, although post-closure activitieswill be more extensive for alternatives in which wastes remain onsite. Forall plans, post closure activities will Include vegetation control, fencerepair, and quarterly groundwater monitoring from existing monitoring wellsto verify that the groundwater Is not Impacted by remedial construction.For plans that do not clean up contaminated soils to background levels,additional groundwater monitoring and site surface maintenance will benecessary for a period of up to 30 years.
Operation and maintenance for the recommended alternative will Involvelandscaping and fence repair at the site, groundwater monitoring from thethree existing onsite monitoring wells, and construction of an additionalshallow monitoring well at the site boundary directly downgradient of soilcontamination Area B. Groundwater monitoring will be performed for a periodof 5 years If no significant contamination is detected 1n the monitoringwells by the end of this period, the remedy will be considered effectiveand further monitoring will not be required. If significant contaminationis detected during the monitoring period, corrective measures will beevaluated.
Annual operation and maintenance costs for the recommended alternative isestimated to be $500 and the present worth is estimated to be $5000
Schedule
Approve Remedial Attion June, 1985Award Cooperative Agreement for Design June, 1985Award Cooperative Agreement for Construction June, 1985
BROUSSARO PROPERTY \,ft
\TRIANGLE CHEMCALPROPERTY LINELOADING DOCK RAM*
LOADING BUILDING
oooooooo
PROCESS BMJDMC NQ 3
REOORO CHEMICAL PROPERTY
E9TMATCO OCPTM Of COMTANIMATED
AREA A 1 -1
AREA 9 1-9
AREA C 1-9
- 4CAMTHCN OWE CONSTRUCTION DETAft.
Fiaure 7TNIANOUI CHEMICAL COMPANY
. TBJJta WORK ARCA9
SECTION A-A
1 UNCONTAMINATED COVER
2 VERTICAL EXTENT OF CONTAMINATION
0 5 TRANSITION TO CLEAN ZONE
TYPICAL S% ACCESS GRADE
SECTION B-6
TYPICAL DETAIL FOR CUT STABILITY
PROCESSBUILDING
N01
f R>E SLOPE DKTATEDtY PftOCESS KffLDMQfOUNDATlO* DCSJON
TYPICAL 5% ACCESS GRADE
SECTION C-C .
180
TYPICAL 5% ACCESS GRAD
LEGEND
NOTE VERTICAL SCALE EXAGGERATED TOSHOW CONSTRUCTION DETAIL
UNCONTAMINATED COVER
TILL ZONE
VEGETATION
1* UNCONTAMINATEDCOVER
VERTICAL EXTENT6* OF CONTAMINATED
SOILS
0 S TRANSITION TOCLEAN ZONE
i/ \i1 UNCONTAMINATED
COVER
VERTICAL EXTENTOF CONTAMINATEDSOILS
O S TRANSITIONTO CLEAN ZONE
TYPICAL 6%ACCESS GRADE
Fiqure 8
TRIANGLE CHEMICAL COMPANY
SOIL TILLING SECTION VIEWS
, /.
I
JUN 1 9
iir. Larry bowarci, fx^cutive Directotifx<i5 Water camussionP o tiox iJU87, Capitol btationAustin, iexos /d/ll-jua7
o ar i ir sowaro
\f tiav*. n viewed tiie rinal bice inspection Hu^ort ror cne constructionactivities at unfe inanyit Chtanical uanprfny and acurowj-eoyt! tnat ailactivities jiav boen ccr^ltted iru- mangle Uiemicai site can nov. ccinssitieo as a completion, and cne environmental protection
| t rocH*-xJ with tlx» at. lot ion t recessi
un or halt oL tne i-nvironmtntax Protection Aj^rjc^, I would iiKi toj comt-nj ttx le>^s I'vater ccnmission on a job well done, ihe Karitoial
/Action was ccrrt letFd on tine and unaer buojct, which can oe attrxbut<-<-j to cnf comDineci t.t torts ot c»ij. involvtsd parties.
L Ljytoo
i«ot)trt fc La/ con Jr , P t.Regional /vaministr^tor
